From 079d98d2bb3837f8d4978ac516b0ab238c4da31b Mon Sep 17 00:00:00 2001
From: Don Morrison <don@mutations.ltd>
Date: Sat, 9 Nov 2019 14:53:25 -0800
Subject: [PATCH 01/32] Add API OpenTelemetry::Adapter

* for access to global config, e.g., OpenTelemetry::Adapter.tracer
---
 api/lib/opentelemetry.rb         |  1 +
 api/lib/opentelemetry/adapter.rb | 23 +++++++++++++++++++++++
 2 files changed, 24 insertions(+)
 create mode 100644 api/lib/opentelemetry/adapter.rb

diff --git a/api/lib/opentelemetry.rb b/api/lib/opentelemetry.rb
index 30162fdb62..3455cf4742 100644
--- a/api/lib/opentelemetry.rb
+++ b/api/lib/opentelemetry.rb
@@ -6,6 +6,7 @@
 require 'logger'
 
 require 'opentelemetry/error'
+require 'opentelemetry/adapter'
 require 'opentelemetry/context'
 require 'opentelemetry/distributed_context'
 require 'opentelemetry/internal'
diff --git a/api/lib/opentelemetry/adapter.rb b/api/lib/opentelemetry/adapter.rb
new file mode 100644
index 0000000000..cecd3ae294
--- /dev/null
+++ b/api/lib/opentelemetry/adapter.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+module OpenTelemetry
+  # The basic interface for Adapter objects
+  class Adapter
+    class << self
+      attr_reader :config
+
+      def install(config = {})
+        @config = config
+        new.install
+      end
+
+      def tracer
+        OpenTelemetry.tracer_factory.tracer(config[:name], config[:version])
+      end
+    end
+  end
+end

From 5ac7d4edd9f45161512fe41859bdf3ce987d5a53 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Fri, 8 Nov 2019 09:55:27 -0800
Subject: [PATCH 02/32] Add faraday instrumentation adapter Gemfile/gemspec

---
 adapters/faraday/Gemfile                      | 11 +++++++
 .../opentelemetry/adapters/faraday/version.rb | 13 ++++++++
 .../opentelemetry-adapters-faraday.gemspec    | 32 +++++++++++++++++++
 3 files changed, 56 insertions(+)
 create mode 100644 adapters/faraday/Gemfile
 create mode 100644 adapters/faraday/lib/opentelemetry/adapters/faraday/version.rb
 create mode 100644 adapters/faraday/opentelemetry-adapters-faraday.gemspec

diff --git a/adapters/faraday/Gemfile b/adapters/faraday/Gemfile
new file mode 100644
index 0000000000..bea08dcb0c
--- /dev/null
+++ b/adapters/faraday/Gemfile
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+source 'https://rubygems.org'
+
+gemspec
+
+gem 'opentelemetry-api', path: '../../api'
diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday/version.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday/version.rb
new file mode 100644
index 0000000000..f7ea89e404
--- /dev/null
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday/version.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+module OpenTelemetry
+  module Adapters
+    module Faraday
+      VERSION = '0.0.0'
+    end
+  end
+end
diff --git a/adapters/faraday/opentelemetry-adapters-faraday.gemspec b/adapters/faraday/opentelemetry-adapters-faraday.gemspec
new file mode 100644
index 0000000000..7673cf1459
--- /dev/null
+++ b/adapters/faraday/opentelemetry-adapters-faraday.gemspec
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+lib = File.expand_path('lib', __dir__)
+$LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
+require 'opentelemetry/adapters/faraday/version'
+
+Gem::Specification.new do |spec|
+  spec.name        = 'opentelemetry-adapters-faraday'
+  spec.version     = OpenTelemetry::Adapters::Faraday::VERSION
+  spec.authors     = ['OpenTelemetry Authors']
+  spec.email       = ['cncf-opentelemetry-contributors@lists.cncf.io']
+
+  spec.summary     = 'Faraday instrumentation adapter for the OpenTelemetry framework'
+  spec.description = 'Faraday instrumentation adapter for the OpenTelemetry framework'
+  spec.homepage    = 'https://github.com/open-telemetry/opentelemetry-ruby'
+  spec.license     = 'Apache-2.0'
+
+  spec.files = ::Dir.glob('lib/**/*.rb') +
+               ::Dir.glob('*.md') +
+               ['LICENSE']
+  spec.require_paths = ['lib']
+  spec.required_ruby_version = '>= 2.4.0'
+
+  spec.add_dependency 'opentelemetry-api', '~> 0.0'
+  spec.add_dependency 'faraday', '~> 0.17.0'
+
+  spec.add_development_dependency 'bundler', '>= 1.17'
+end

From 3f7f6b080e72b812b1f61e0241ba0bb8d9db1d18 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Mon, 11 Nov 2019 11:33:52 -0800
Subject: [PATCH 03/32] Add faraday instrumentation adapter

---
 .../faraday/lib/opentelemetry/adapters.rb     | 12 ++++++
 .../lib/opentelemetry/adapters/faraday.rb     | 21 +++++++++
 .../opentelemetry/adapters/faraday/adapter.rb | 33 ++++++++++++++
 .../faraday/middlewares/tracer_middleware.rb  | 43 +++++++++++++++++++
 .../adapters/faraday/patches/rack_builder.rb  | 26 +++++++++++
 5 files changed, 135 insertions(+)
 create mode 100644 adapters/faraday/lib/opentelemetry/adapters.rb
 create mode 100644 adapters/faraday/lib/opentelemetry/adapters/faraday.rb
 create mode 100644 adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
 create mode 100644 adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
 create mode 100644 adapters/faraday/lib/opentelemetry/adapters/faraday/patches/rack_builder.rb

diff --git a/adapters/faraday/lib/opentelemetry/adapters.rb b/adapters/faraday/lib/opentelemetry/adapters.rb
new file mode 100644
index 0000000000..e5956b543c
--- /dev/null
+++ b/adapters/faraday/lib/opentelemetry/adapters.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+module OpenTelemetry
+  # "Instrumentation adapters" are specified by
+  # https://github.com/open-telemetry/opentelemetry-specification/blob/57714f7547fe4dcb342ad0ad10a80d86118431c7/specification/overview.md#instrumentation-adapters
+  module Adapters
+  end
+end
diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday.rb
new file mode 100644
index 0000000000..80695f4ac4
--- /dev/null
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+module OpenTelemetry
+  module Adapters
+    module Faraday
+      module_function
+
+      TRACER_NAME = 'faraday'
+      TRACER_VERSION = Gem.loaded_specs[TRACER_NAME].version.to_s
+
+      def install(config = {name: TRACER_NAME, version: TRACER_VERSION})
+        require_relative 'faraday/adapter'
+        Faraday::Adapter.install(config)
+      end
+    end
+  end
+end
diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
new file mode 100644
index 0000000000..5625af4aa0
--- /dev/null
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require_relative 'middlewares/tracer_middleware'
+require_relative 'patches/rack_builder'
+
+module OpenTelemetry
+  module Adapters
+    module Faraday
+      class Adapter < OpenTelemetry::Adapter
+        def install
+          register_tracer_middleware
+          use_middleware_by_default
+        end
+
+        private
+
+        def register_tracer_middleware
+          ::Faraday::Middleware.register_middleware(
+            open_telemetry: Middlewares::TracerMiddleware
+          )
+        end
+
+        def use_middleware_by_default
+          ::Faraday::RackBuilder.prepend(Patches::RackBuilder)
+        end
+      end
+    end
+  end
+end
diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
new file mode 100644
index 0000000000..b038c2c474
--- /dev/null
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+module OpenTelemetry
+  module Adapters
+    module Faraday
+      module Middlewares
+        class TracerMiddleware < ::Faraday::Middleware
+          def call(env)
+            tracer.in_span(env.url.to_s,
+                          attributes: { 'component' => 'http',
+                                        'http.method' => env.method },
+                          kind: :client) do |span|
+              trace_request(span, env)
+
+              app.call(env).on_complete { |resp| trace_response(span, resp) }
+            end
+          end
+
+          private
+
+          attr_reader :app
+
+          def tracer
+            Faraday::Adapter.tracer
+          end
+
+          def trace_request(span, env)
+            span.set_attribute('http.url', env.url.to_s)
+          end
+
+          def trace_response(span, response)
+            span.set_attribute('http.status_code', response.status)
+            span.set_attribute('http.status_text', response.reason_phrase)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday/patches/rack_builder.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday/patches/rack_builder.rb
new file mode 100644
index 0000000000..1292ec99a8
--- /dev/null
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday/patches/rack_builder.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+require_relative '../middlewares/tracer_middleware'
+
+module OpenTelemetry
+  module Adapters
+    module Faraday
+      module Patches
+        # Module to be prepended to force Faraday to use the middleware by
+        # default so the user doesn't have to call `use` for every connection.
+        module RackBuilder
+          def adapter(*args)
+            use(:open_telemetry) unless @handlers.any? do |handler|
+              handler.klass == Middlewares::TracerMiddleware
+            end
+
+            super
+          end
+        end
+      end
+    end
+  end
+end

From ed31c858322779c9fb892f2a931b457457ffeab9 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Fri, 8 Nov 2019 11:21:23 -0800
Subject: [PATCH 04/32] Add faraday example with docker-compose service

* e.g.,
  $ docker-compose run ex-adapter-faraday
  $ ruby faraday.rb

Expected: console output of SpanData
---
 adapters/faraday/example/Gemfile    |  7 +++++++
 adapters/faraday/example/faraday.rb | 21 +++++++++++++++++++++
 docker-compose.yml                  |  4 ++++
 3 files changed, 32 insertions(+)
 create mode 100644 adapters/faraday/example/Gemfile
 create mode 100644 adapters/faraday/example/faraday.rb

diff --git a/adapters/faraday/example/Gemfile b/adapters/faraday/example/Gemfile
new file mode 100644
index 0000000000..1c162edde6
--- /dev/null
+++ b/adapters/faraday/example/Gemfile
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+source 'https://rubygems.org'
+
+gem 'faraday'
+gem 'opentelemetry-api', path: '../../../api'
+gem 'opentelemetry-sdk', path: '../../../sdk'
diff --git a/adapters/faraday/example/faraday.rb b/adapters/faraday/example/faraday.rb
new file mode 100644
index 0000000000..024e195096
--- /dev/null
+++ b/adapters/faraday/example/faraday.rb
@@ -0,0 +1,21 @@
+require 'rubygems'
+require 'bundler/setup'
+
+require 'faraday'
+require 'opentelemetry/sdk'
+require_relative '../lib/opentelemetry/adapters/faraday'
+
+# Set preferred tracer implementation:
+SDK = OpenTelemetry::SDK
+
+factory = OpenTelemetry.tracer_factory = SDK::Trace::TracerFactory.new
+factory.add_span_processor(
+  SDK::Trace::Export::SimpleSpanProcessor.new(
+    SDK::Trace::Export::ConsoleSpanExporter.new
+  )
+)
+
+OpenTelemetry::Adapters::Faraday.install(name: 'faraday-example', version: '1.0')
+
+conn = Faraday.new('http://example.com')
+conn.get '/'
diff --git a/docker-compose.yml b/docker-compose.yml
index 8a48f1a0d0..e926ecfa64 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -24,6 +24,10 @@ services:
       context: .
     working_dir: /app
 
+  ex-adapter-faraday:
+    <<: *base
+    working_dir: /app/adapters/faraday/example
+
   sdk:
     <<: *base
     working_dir: /app/sdk

From 22ccf4fef264c0208b6b016d6f65888f93bfb21d Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Tue, 12 Nov 2019 14:00:13 -0800
Subject: [PATCH 05/32] Avoid hard-dependency on faraday

* want to be able to ship more instrumentation than a user needs,
  let the auto-installer determine what is applicable
---
 adapters/faraday/opentelemetry-adapters-faraday.gemspec | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/adapters/faraday/opentelemetry-adapters-faraday.gemspec b/adapters/faraday/opentelemetry-adapters-faraday.gemspec
index 7673cf1459..eee39b4193 100644
--- a/adapters/faraday/opentelemetry-adapters-faraday.gemspec
+++ b/adapters/faraday/opentelemetry-adapters-faraday.gemspec
@@ -26,7 +26,7 @@ Gem::Specification.new do |spec|
   spec.required_ruby_version = '>= 2.4.0'
 
   spec.add_dependency 'opentelemetry-api', '~> 0.0'
-  spec.add_dependency 'faraday', '~> 0.17.0'
 
   spec.add_development_dependency 'bundler', '>= 1.17'
+  spec.add_development_dependency 'faraday', '~> 0.17.0'
 end

From 7562579c07058a02468a51f499bb5d546deb1deb Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Wed, 13 Nov 2019 13:15:44 -0800
Subject: [PATCH 06/32] Fix undefined method `version' for nil:NilClass

* when 'faraday' isn't loaded/required already

e.g.,
irb> require 'opentelemetry/adapters/faraday'
irb> OpenTelemetry::Adapters::Faraday.install
---
 adapters/faraday/lib/opentelemetry/adapters/faraday.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday.rb
index 80695f4ac4..fe361bcd4d 100644
--- a/adapters/faraday/lib/opentelemetry/adapters/faraday.rb
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday.rb
@@ -10,7 +10,7 @@ module Faraday
       module_function
 
       TRACER_NAME = 'faraday'
-      TRACER_VERSION = Gem.loaded_specs[TRACER_NAME].version.to_s
+      TRACER_VERSION = Gem.loaded_specs[TRACER_NAME]&.version.to_s
 
       def install(config = {name: TRACER_NAME, version: TRACER_VERSION})
         require_relative 'faraday/adapter'

From 698735129e60db47c32cb53ac0e4b7459b114f1f Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Tue, 12 Nov 2019 14:06:57 -0800
Subject: [PATCH 07/32] Doc: reminder to handle common use case

---
 adapters/faraday/lib/opentelemetry/adapters.rb | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/adapters/faraday/lib/opentelemetry/adapters.rb b/adapters/faraday/lib/opentelemetry/adapters.rb
index e5956b543c..55295042cf 100644
--- a/adapters/faraday/lib/opentelemetry/adapters.rb
+++ b/adapters/faraday/lib/opentelemetry/adapters.rb
@@ -7,6 +7,8 @@
 module OpenTelemetry
   # "Instrumentation adapters" are specified by
   # https://github.com/open-telemetry/opentelemetry-specification/blob/57714f7547fe4dcb342ad0ad10a80d86118431c7/specification/overview.md#instrumentation-adapters
+  #
+  # Adapters should be able to handle the case when the library is not installed on a user's system.
   module Adapters
   end
 end

From 92ba1bc7bd7279e860150a01fb33a0327988b20f Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Tue, 12 Nov 2019 17:49:42 -0800
Subject: [PATCH 08/32] Add explicit 'require' statements in faraday/adapter

* will only be called after Adapters::Faraday.install
* reduces burden on caller
---
 .../faraday/lib/opentelemetry/adapters/faraday/adapter.rb    | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
index 5625af4aa0..3cb4f7abc1 100644
--- a/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
@@ -4,6 +4,11 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
+# TODO: General Question: should adapters explicitly load the libraries they depend on?
+# Or, should adapters assume that the libraries are already loaded by the caller/user?
+require 'faraday'
+require 'opentelemetry/adapter'
+
 require_relative 'middlewares/tracer_middleware'
 require_relative 'patches/rack_builder'
 

From 60d41d6edc3e6a0b34707b9a90260128e5dfdad7 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Tue, 12 Nov 2019 18:09:13 -0800
Subject: [PATCH 09/32] Use in_span(attributes:) instead of set_attribute

* for performance, since span.set_attribute involves a mutex, etc.
---
 .../adapters/faraday/middlewares/tracer_middleware.rb    | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
index b038c2c474..e252ab988d 100644
--- a/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
@@ -12,10 +12,9 @@ class TracerMiddleware < ::Faraday::Middleware
           def call(env)
             tracer.in_span(env.url.to_s,
                           attributes: { 'component' => 'http',
-                                        'http.method' => env.method },
+                                        'http.method' => env.method,
+                                        'http.url' => env.url.to_s },
                           kind: :client) do |span|
-              trace_request(span, env)
-
               app.call(env).on_complete { |resp| trace_response(span, resp) }
             end
           end
@@ -28,10 +27,6 @@ def tracer
             Faraday::Adapter.tracer
           end
 
-          def trace_request(span, env)
-            span.set_attribute('http.url', env.url.to_s)
-          end
-
           def trace_response(span, response)
             span.set_attribute('http.status_code', response.status)
             span.set_attribute('http.status_text', response.reason_phrase)

From 33f28c01901b90d68d5a74c176660445be71925f Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Mon, 11 Nov 2019 11:19:06 -0800
Subject: [PATCH 10/32] Change SDK::Trace::TracerFactory to subclass API's
 TracerFactory

* to allow access to #http_text_format
---
 sdk/lib/opentelemetry/sdk/trace/tracer_factory.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sdk/lib/opentelemetry/sdk/trace/tracer_factory.rb b/sdk/lib/opentelemetry/sdk/trace/tracer_factory.rb
index 5f17334bf3..8a021c82b4 100644
--- a/sdk/lib/opentelemetry/sdk/trace/tracer_factory.rb
+++ b/sdk/lib/opentelemetry/sdk/trace/tracer_factory.rb
@@ -8,7 +8,7 @@ module OpenTelemetry
   module SDK
     module Trace
       # {TracerFactory} is the SDK implementation of {OpenTelemetry::Trace::TracerFactory}.
-      class TracerFactory
+      class TracerFactory < OpenTelemetry::Trace::TracerFactory
         Key = Struct.new(:name, :version)
         private_constant(:Key)
 

From 937cf6ca2e9ccfc329049146e075844fcf94fb99 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Wed, 13 Nov 2019 13:21:32 -0800
Subject: [PATCH 11/32] Add context propagation

---
 .../adapters/faraday/middlewares/tracer_middleware.rb | 11 +++++++++++
 api/lib/opentelemetry/adapter.rb                      |  4 ++++
 2 files changed, 15 insertions(+)

diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
index e252ab988d..6500736a82 100644
--- a/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
@@ -15,6 +15,8 @@ def call(env)
                                         'http.method' => env.method,
                                         'http.url' => env.url.to_s },
                           kind: :client) do |span|
+              propagate_context(span, env)
+
               app.call(env).on_complete { |resp| trace_response(span, resp) }
             end
           end
@@ -23,6 +25,15 @@ def call(env)
 
           attr_reader :app
 
+          def propagate_context(span, env)
+            formatter.extract(env)
+            formatter.inject(span.context, env.request_headers)
+          end
+
+          def formatter
+            Faraday::Adapter.http_formatter
+          end
+
           def tracer
             Faraday::Adapter.tracer
           end
diff --git a/api/lib/opentelemetry/adapter.rb b/api/lib/opentelemetry/adapter.rb
index cecd3ae294..e56df8613c 100644
--- a/api/lib/opentelemetry/adapter.rb
+++ b/api/lib/opentelemetry/adapter.rb
@@ -15,6 +15,10 @@ def install(config = {})
         new.install
       end
 
+      def http_formatter
+        OpenTelemetry.tracer_factory.http_text_format
+      end
+
       def tracer
         OpenTelemetry.tracer_factory.tracer(config[:name], config[:version])
       end

From d42721b4f2be43c3727cb51adf1c9368fcc9e4e8 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Wed, 13 Nov 2019 14:24:47 -0800
Subject: [PATCH 12/32] Fix occasional test failure in sdk
 batch_span_processor_test

* RE: "failures on heavily loaded CI server" -- increase delta
  experimentally, by 10x
---
 .../sdk/trace/export/batch_span_processor_test.rb             | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sdk/test/opentelemetry/sdk/trace/export/batch_span_processor_test.rb b/sdk/test/opentelemetry/sdk/trace/export/batch_span_processor_test.rb
index bb1fa6cc13..40200d4696 100644
--- a/sdk/test/opentelemetry/sdk/trace/export/batch_span_processor_test.rb
+++ b/sdk/test/opentelemetry/sdk/trace/export/batch_span_processor_test.rb
@@ -221,7 +221,7 @@ def to_span_data
     end
 
     describe 'normally' do
-      let(:exporter_sleeps_for_millis) { exporter_timeout_millis - 1 }
+      let(:exporter_sleeps_for_millis) { exporter_timeout_millis - 10 }
 
       it 'exporter is not interrupted' do
         _(exporter.state).must_equal(:not_interrupted)
@@ -229,7 +229,7 @@ def to_span_data
     end
 
     describe 'when exporter runs too long' do
-      let(:exporter_sleeps_for_millis) { exporter_timeout_millis + 1 }
+      let(:exporter_sleeps_for_millis) { exporter_timeout_millis + 10 }
 
       it 'is interrupted by a timeout' do
         _(exporter.state).must_equal(:called)

From 814e3307097c02f5841d01178cd40d0195cd6546 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Thu, 14 Nov 2019 09:37:58 -0800
Subject: [PATCH 13/32] Don't extract context, just inject

hints:
* for outbound requests:
  inject current span context into request headers
* for inbound requests:
  extract remote span context from request headers,
  start a new span with parent context (using the extracted
  context)
---
 .../adapters/faraday/middlewares/tracer_middleware.rb           | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
index 6500736a82..33405567fd 100644
--- a/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
@@ -25,8 +25,8 @@ def call(env)
 
           attr_reader :app
 
+          # Outbound requests should only need to inject the current span.
           def propagate_context(span, env)
-            formatter.extract(env)
             formatter.inject(span.context, env.request_headers)
           end
 

From 4ee20b1b9baef7e21e1d7b26cc17c4bda7bf0c4a Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Thu, 14 Nov 2019 10:11:58 -0800
Subject: [PATCH 14/32] Load tracer_version lazily

* TRACER_VERSION can get locked to empty string if faraday isn't required yet
---
 adapters/faraday/lib/opentelemetry/adapters/faraday.rb | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday.rb
index fe361bcd4d..86baed9558 100644
--- a/adapters/faraday/lib/opentelemetry/adapters/faraday.rb
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday.rb
@@ -10,12 +10,17 @@ module Faraday
       module_function
 
       TRACER_NAME = 'faraday'
-      TRACER_VERSION = Gem.loaded_specs[TRACER_NAME]&.version.to_s
 
-      def install(config = {name: TRACER_NAME, version: TRACER_VERSION})
+      def install(config = {name: TRACER_NAME,
+                            version: tracer_version})
         require_relative 'faraday/adapter'
         Faraday::Adapter.install(config)
       end
+
+      def tracer_version
+        Gem.loaded_specs[TRACER_NAME]&.version.to_s
+      end
+      private_class_method(:tracer_version)
     end
   end
 end

From 915b0520e74a90bb102241df152f986f1a2fa094 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Thu, 14 Nov 2019 10:35:10 -0800
Subject: [PATCH 15/32] Allow auto-installer to inject a tracer

* allow (auto) installer to bind tracer to instrumentation
* config[:tracer] will override default_tracer
---
 api/lib/opentelemetry/adapter.rb | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/api/lib/opentelemetry/adapter.rb b/api/lib/opentelemetry/adapter.rb
index e56df8613c..90c02ce613 100644
--- a/api/lib/opentelemetry/adapter.rb
+++ b/api/lib/opentelemetry/adapter.rb
@@ -4,22 +4,30 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
+require 'opentelemetry'
+
 module OpenTelemetry
   # The basic interface for Adapter objects
   class Adapter
     class << self
-      attr_reader :config
+      attr_reader :config,
+                  :http_formatter,
+                  :tracer
 
       def install(config = {})
         @config = config
+        @http_formatter = config[:http_formatter] || default_http_formatter
+        @tracer = config[:tracer] || default_tracer
         new.install
       end
 
-      def http_formatter
+      private
+
+      def default_http_formatter
         OpenTelemetry.tracer_factory.http_text_format
       end
 
-      def tracer
+      def default_tracer
         OpenTelemetry.tracer_factory.tracer(config[:name], config[:version])
       end
     end

From 89ba2cb3292eaaebf3437bf5cbea319131b5f191 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Tue, 19 Nov 2019 17:31:07 -0800
Subject: [PATCH 16/32] Fix circular loading issue

---
 api/lib/opentelemetry/adapter.rb | 2 --
 1 file changed, 2 deletions(-)

diff --git a/api/lib/opentelemetry/adapter.rb b/api/lib/opentelemetry/adapter.rb
index 90c02ce613..d4a0c8ec4c 100644
--- a/api/lib/opentelemetry/adapter.rb
+++ b/api/lib/opentelemetry/adapter.rb
@@ -4,8 +4,6 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-require 'opentelemetry'
-
 module OpenTelemetry
   # The basic interface for Adapter objects
   class Adapter

From a45dac29a19d8b3e40a2be1b895b1257835f6b5d Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Sat, 23 Nov 2019 15:55:16 -0800
Subject: [PATCH 17/32] Avoid requiring changes to API (OpenTelemetry::Adapter)

* avoid making API changes now by inlining required methods
  (#propagator)
---
 .../opentelemetry/adapters/faraday/adapter.rb | 27 ++++++++++++---
 .../faraday/middlewares/tracer_middleware.rb  |  6 ++--
 api/lib/opentelemetry.rb                      |  1 -
 api/lib/opentelemetry/adapter.rb              | 33 -------------------
 4 files changed, 26 insertions(+), 41 deletions(-)
 delete mode 100644 api/lib/opentelemetry/adapter.rb

diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
index 3cb4f7abc1..7fe860138e 100644
--- a/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
@@ -4,10 +4,8 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-# TODO: General Question: should adapters explicitly load the libraries they depend on?
-# Or, should adapters assume that the libraries are already loaded by the caller/user?
 require 'faraday'
-require 'opentelemetry/adapter'
+require 'opentelemetry'
 
 require_relative 'middlewares/tracer_middleware'
 require_relative 'patches/rack_builder'
@@ -15,7 +13,28 @@
 module OpenTelemetry
   module Adapters
     module Faraday
-      class Adapter < OpenTelemetry::Adapter
+      class Adapter
+        class << self
+          attr_reader :config,
+                      :propagator,
+                      :tracer
+
+          def install(config = {})
+            @config = config
+            @propagator = OpenTelemetry.tracer_factory.rack_http_text_format
+            @tracer = config[:tracer] || default_tracer
+
+            new.install
+          end
+
+          private
+
+          def default_tracer
+            OpenTelemetry.tracer_factory.tracer(config[:name],
+                                                config[:version])
+          end
+        end
+
         def install
           register_tracer_middleware
           use_middleware_by_default
diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
index 33405567fd..3c1551d09f 100644
--- a/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
@@ -27,11 +27,11 @@ def call(env)
 
           # Outbound requests should only need to inject the current span.
           def propagate_context(span, env)
-            formatter.inject(span.context, env.request_headers)
+            propagator.inject(span.context, env.request_headers)
           end
 
-          def formatter
-            Faraday::Adapter.http_formatter
+          def propagator
+            Faraday::Adapter.propagator
           end
 
           def tracer
diff --git a/api/lib/opentelemetry.rb b/api/lib/opentelemetry.rb
index 3455cf4742..30162fdb62 100644
--- a/api/lib/opentelemetry.rb
+++ b/api/lib/opentelemetry.rb
@@ -6,7 +6,6 @@
 require 'logger'
 
 require 'opentelemetry/error'
-require 'opentelemetry/adapter'
 require 'opentelemetry/context'
 require 'opentelemetry/distributed_context'
 require 'opentelemetry/internal'
diff --git a/api/lib/opentelemetry/adapter.rb b/api/lib/opentelemetry/adapter.rb
deleted file mode 100644
index d4a0c8ec4c..0000000000
--- a/api/lib/opentelemetry/adapter.rb
+++ /dev/null
@@ -1,33 +0,0 @@
-# frozen_string_literal: true
-
-# Copyright 2019 OpenTelemetry Authors
-#
-# SPDX-License-Identifier: Apache-2.0
-
-module OpenTelemetry
-  # The basic interface for Adapter objects
-  class Adapter
-    class << self
-      attr_reader :config,
-                  :http_formatter,
-                  :tracer
-
-      def install(config = {})
-        @config = config
-        @http_formatter = config[:http_formatter] || default_http_formatter
-        @tracer = config[:tracer] || default_tracer
-        new.install
-      end
-
-      private
-
-      def default_http_formatter
-        OpenTelemetry.tracer_factory.http_text_format
-      end
-
-      def default_tracer
-        OpenTelemetry.tracer_factory.tracer(config[:name], config[:version])
-      end
-    end
-  end
-end

From a558f7195f146652154ac423eb03b7dd22417acc Mon Sep 17 00:00:00 2001
From: Don Morrison <don@mutations.ltd>
Date: Wed, 4 Dec 2019 13:57:46 -0800
Subject: [PATCH 18/32] sig-feedback: remove name and version from config

Removes the name and version from the config as the spec defines
these as coming from the instrumentation/adapter and not from the
instrumented library.

Adds convenience methods for the name and version and provide
those on the `Faraday` adapter class.

Updates the tracer configuration to use the new name and version.

Updates the example to remove the name and version from the call.
---
 adapters/faraday/example/faraday.rb            |  2 +-
 .../lib/opentelemetry/adapters/faraday.rb      | 18 +++++++++++-------
 .../opentelemetry/adapters/faraday/adapter.rb  | 14 ++++++--------
 3 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/adapters/faraday/example/faraday.rb b/adapters/faraday/example/faraday.rb
index 024e195096..c66e96eaeb 100644
--- a/adapters/faraday/example/faraday.rb
+++ b/adapters/faraday/example/faraday.rb
@@ -15,7 +15,7 @@
   )
 )
 
-OpenTelemetry::Adapters::Faraday.install(name: 'faraday-example', version: '1.0')
+OpenTelemetry::Adapters::Faraday.install
 
 conn = Faraday.new('http://example.com')
 conn.get '/'
diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday.rb
index 86baed9558..3790170895 100644
--- a/adapters/faraday/lib/opentelemetry/adapters/faraday.rb
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday.rb
@@ -9,18 +9,22 @@ module Adapters
     module Faraday
       module_function
 
-      TRACER_NAME = 'faraday'
-
-      def install(config = {name: TRACER_NAME,
-                            version: tracer_version})
+      def install(config = {})
         require_relative 'faraday/adapter'
         Faraday::Adapter.install(config)
       end
 
-      def tracer_version
-        Gem.loaded_specs[TRACER_NAME]&.version.to_s
+      # Convenience method to access the nested module name
+      def name
+        Module.nesting[0].to_s
+      end
+
+      # Convenience method to access the adapter version
+      def version
+        VERSION
       end
-      private_class_method(:tracer_version)
     end
   end
 end
+
+require_relative './faraday/version'
diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
index 7fe860138e..2f4e9ad713 100644
--- a/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
@@ -16,22 +16,20 @@ module Faraday
       class Adapter
         class << self
           attr_reader :config,
-                      :propagator,
-                      :tracer
+                      :propagator
 
           def install(config = {})
             @config = config
             @propagator = OpenTelemetry.tracer_factory.rack_http_text_format
-            @tracer = config[:tracer] || default_tracer
 
             new.install
           end
 
-          private
-
-          def default_tracer
-            OpenTelemetry.tracer_factory.tracer(config[:name],
-                                                config[:version])
+          def tracer
+            @tracer ||= OpenTelemetry.tracer_factory.tracer(
+              Faraday.name,
+              Faraday.version
+            )
           end
         end
 

From 00ad878595f15e4ba00bf28cffbb7ec2ce3a79a6 Mon Sep 17 00:00:00 2001
From: Don Morrison <don@mutations.ltd>
Date: Wed, 4 Dec 2019 13:59:08 -0800
Subject: [PATCH 19/32] sig-feedback: Use the http text format for propagation

Update the `propagator` to use the plain http text format rather
than the rack version.
---
 adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
index 2f4e9ad713..873c60c42e 100644
--- a/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
@@ -20,7 +20,7 @@ class << self
 
           def install(config = {})
             @config = config
-            @propagator = OpenTelemetry.tracer_factory.rack_http_text_format
+            @propagator = OpenTelemetry.tracer_factory.http_text_format
 
             new.install
           end

From 1658d2e37f54ab1060acb17ff43b08b604ac57bd Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Tue, 19 Nov 2019 17:30:22 -0800
Subject: [PATCH 20/32] Tests: Change Gemfile, gemspec, add Rakefile

* Gemfile: opentelemetry-sdk is only required for tests
---
 adapters/faraday/Gemfile                           |  4 ++++
 adapters/faraday/Rakefile                          | 14 ++++++++++++++
 .../faraday/opentelemetry-adapters-faraday.gemspec |  5 +++++
 3 files changed, 23 insertions(+)
 create mode 100644 adapters/faraday/Rakefile

diff --git a/adapters/faraday/Gemfile b/adapters/faraday/Gemfile
index bea08dcb0c..a022b20230 100644
--- a/adapters/faraday/Gemfile
+++ b/adapters/faraday/Gemfile
@@ -9,3 +9,7 @@ source 'https://rubygems.org'
 gemspec
 
 gem 'opentelemetry-api', path: '../../api'
+
+group :test do
+  gem 'opentelemetry-sdk', path: '../../sdk'
+end
diff --git a/adapters/faraday/Rakefile b/adapters/faraday/Rakefile
new file mode 100644
index 0000000000..4919bebd54
--- /dev/null
+++ b/adapters/faraday/Rakefile
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require 'bundler/gem_tasks'
+require 'rake/testtask'
+
+Rake::TestTask.new :test do |t|
+  t.libs << 'test'
+  t.libs << 'lib'
+  t.test_files = FileList['test/**/*_test.rb']
+end
\ No newline at end of file
diff --git a/adapters/faraday/opentelemetry-adapters-faraday.gemspec b/adapters/faraday/opentelemetry-adapters-faraday.gemspec
index eee39b4193..df4a735e24 100644
--- a/adapters/faraday/opentelemetry-adapters-faraday.gemspec
+++ b/adapters/faraday/opentelemetry-adapters-faraday.gemspec
@@ -27,6 +27,11 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency 'opentelemetry-api', '~> 0.0'
 
+  spec.add_development_dependency 'appraisal', '~> 2.2.0'
   spec.add_development_dependency 'bundler', '>= 1.17'
   spec.add_development_dependency 'faraday', '~> 0.17.0'
+  spec.add_development_dependency 'minitest', '~> 5.0'
+  spec.add_development_dependency 'opentelemetry-sdk', '~> 0.0'
+  spec.add_development_dependency 'simplecov', '~> 0.17.1'
+  spec.add_development_dependency 'webmock', '~> 3.7.6'
 end

From 21c8ada3a713c93675a509ed2ca512708dd43dc4 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Tue, 19 Nov 2019 17:30:48 -0800
Subject: [PATCH 21/32] Add test_helper and first test

* note: adapter.install effects aren't localized, so test order
  matters

Update tests to avoid passing name, version to .install

* name and version are now determined internally and shouldn't usually
  be passed in explicitly
---
 .../opentelemetry/adapters/faraday_test.rb    | 35 +++++++++++++++++++
 adapters/faraday/test/test_helper.rb          | 22 ++++++++++++
 2 files changed, 57 insertions(+)
 create mode 100644 adapters/faraday/test/opentelemetry/adapters/faraday_test.rb
 create mode 100644 adapters/faraday/test/test_helper.rb

diff --git a/adapters/faraday/test/opentelemetry/adapters/faraday_test.rb b/adapters/faraday/test/opentelemetry/adapters/faraday_test.rb
new file mode 100644
index 0000000000..099621b30d
--- /dev/null
+++ b/adapters/faraday/test/opentelemetry/adapters/faraday_test.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require 'test_helper'
+
+require_relative '../../../lib/opentelemetry/adapters/faraday'
+
+describe OpenTelemetry::Adapters::Faraday do
+  let(:adapter) { OpenTelemetry::Adapters::Faraday }
+  let(:exporter) { EXPORTER }
+
+  before do
+    adapter.install
+    exporter.reset
+  end
+
+  describe 'tracing' do
+    before do
+      stub_request(:any, 'example.com')
+    end
+
+    it 'before request' do
+      _(exporter.finished_spans.size).must_equal 0
+    end
+
+    it 'after request' do
+      ::Faraday.new('http://example.com').get('/')
+
+      _(exporter.finished_spans.size).must_equal 1
+    end
+  end
+end
diff --git a/adapters/faraday/test/test_helper.rb b/adapters/faraday/test/test_helper.rb
new file mode 100644
index 0000000000..347cc5d908
--- /dev/null
+++ b/adapters/faraday/test/test_helper.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require 'faraday'
+
+require 'opentelemetry/sdk'
+
+require 'minitest/autorun'
+require 'webmock/minitest'
+
+# global opentelemetry-sdk setup:
+sdk = OpenTelemetry::SDK
+exporter = sdk::Trace::Export::InMemorySpanExporter.new
+span_processor = sdk::Trace::Export::SimpleSpanProcessor.new(exporter)
+OpenTelemetry.tracer_factory = sdk::Trace::TracerFactory.new.tap do |factory|
+  factory.add_span_processor(span_processor)
+end
+
+EXPORTER = exporter
\ No newline at end of file

From eb243a98d149aa55be8dd915622a6d7dce280bf4 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Tue, 19 Nov 2019 17:41:36 -0800
Subject: [PATCH 22/32] Add appraisals for running tests against multiple
 versions

example:
$ bundle exec appraisal install
$ bundle exec appraisal rake test
---
 .gitignore                                     |  3 +++
 adapters/faraday/Appraisals                    | 11 +++++++++++
 adapters/faraday/gemfiles/faraday_0.13.gemfile | 12 ++++++++++++
 adapters/faraday/gemfiles/faraday_0.16.gemfile | 12 ++++++++++++
 adapters/faraday/gemfiles/faraday_0.17.gemfile | 12 ++++++++++++
 5 files changed, 50 insertions(+)
 create mode 100644 adapters/faraday/Appraisals
 create mode 100644 adapters/faraday/gemfiles/faraday_0.13.gemfile
 create mode 100644 adapters/faraday/gemfiles/faraday_0.16.gemfile
 create mode 100644 adapters/faraday/gemfiles/faraday_0.17.gemfile

diff --git a/.gitignore b/.gitignore
index ec2888c245..d1f826b1b0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,6 @@
 **/coverage
 **/*.gem
 **/.bundle
+
+# Appraisals
+adapters/**/*.gemfile.lock
diff --git a/adapters/faraday/Appraisals b/adapters/faraday/Appraisals
new file mode 100644
index 0000000000..845f66b1e6
--- /dev/null
+++ b/adapters/faraday/Appraisals
@@ -0,0 +1,11 @@
+appraise "faraday-0.17" do
+  gem "faraday", "0.17.0"
+end
+
+appraise "faraday-0.16" do
+  gem "faraday", "0.16.2"
+end
+
+appraise "faraday-0.13" do
+  gem "faraday", "0.13.1"
+end
diff --git a/adapters/faraday/gemfiles/faraday_0.13.gemfile b/adapters/faraday/gemfiles/faraday_0.13.gemfile
new file mode 100644
index 0000000000..58b4980336
--- /dev/null
+++ b/adapters/faraday/gemfiles/faraday_0.13.gemfile
@@ -0,0 +1,12 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "opentelemetry-api", path: "../../../api"
+gem "faraday", "0.13.1"
+
+group :test do
+  gem "opentelemetry-sdk", path: "../../../sdk"
+end
+
+gemspec path: "../"
diff --git a/adapters/faraday/gemfiles/faraday_0.16.gemfile b/adapters/faraday/gemfiles/faraday_0.16.gemfile
new file mode 100644
index 0000000000..d9dd2b2548
--- /dev/null
+++ b/adapters/faraday/gemfiles/faraday_0.16.gemfile
@@ -0,0 +1,12 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "opentelemetry-api", path: "../../../api"
+gem "faraday", "0.16.2"
+
+group :test do
+  gem "opentelemetry-sdk", path: "../../../sdk"
+end
+
+gemspec path: "../"
diff --git a/adapters/faraday/gemfiles/faraday_0.17.gemfile b/adapters/faraday/gemfiles/faraday_0.17.gemfile
new file mode 100644
index 0000000000..650108af52
--- /dev/null
+++ b/adapters/faraday/gemfiles/faraday_0.17.gemfile
@@ -0,0 +1,12 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "opentelemetry-api", path: "../../../api"
+gem "faraday", "0.17.0"
+
+group :test do
+  gem "opentelemetry-sdk", path: "../../../sdk"
+end
+
+gemspec path: "../"

From cfcdf5f6aca8c8392ea697653ea8bd4bcfdc7dad Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Thu, 21 Nov 2019 10:28:48 -0800
Subject: [PATCH 23/32] Add Circle CI config

---
 .circleci/config.yml | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index e20f49bf9a..8d12d84857 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -40,6 +40,13 @@ commands:
       - run:
           name: CI (Jaeger)
           command: "cd exporters/jaeger && bundle exec rake"
+      - run:
+          name: Bundle + CI (Adapters - Faraday)
+          command: |
+            cd adapters/faraday
+            gem install --no-document bundler && bundle install --jobs=3 --retry=3
+            bundle exec appraisal install
+            bundle exec appraisal rake test
   rake-release:
     steps:
       - checkout

From dd680bb88f3c3c8670e7561ccd631e5410d023ea Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Mon, 25 Nov 2019 16:24:05 -0800
Subject: [PATCH 24/32] Add TracerMiddleware test

---
 .../middlewares/tracer_middleware_test.rb     | 53 +++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 adapters/faraday/test/opentelemetry/adapters/faraday/middlewares/tracer_middleware_test.rb

diff --git a/adapters/faraday/test/opentelemetry/adapters/faraday/middlewares/tracer_middleware_test.rb b/adapters/faraday/test/opentelemetry/adapters/faraday/middlewares/tracer_middleware_test.rb
new file mode 100644
index 0000000000..016e79acfb
--- /dev/null
+++ b/adapters/faraday/test/opentelemetry/adapters/faraday/middlewares/tracer_middleware_test.rb
@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require 'test_helper'
+
+# require Adapter so .install method is found:
+require_relative '../../../../../lib/opentelemetry/adapters/faraday/adapter'
+require_relative '../../../../../lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware'
+
+describe OpenTelemetry::Adapters::Faraday::Middlewares::TracerMiddleware do
+  let(:adapter) { OpenTelemetry::Adapters::Faraday }
+  let(:exporter) { EXPORTER }
+
+  let(:client) do
+    ::Faraday.new('http://example.com') do |builder|
+      builder.adapter(:test) do |stub|
+        stub.get('/success') { |_| [200, {}, 'OK'] }
+        stub.get('/failure') { |_| [500, {}, 'OK'] }
+        stub.get('/not_found') { |_| [404, {}, 'OK'] }
+      end
+    end
+  end
+
+  before do
+    adapter.install
+    exporter.reset
+  end
+
+  describe 'first span' do
+    let(:span) { exporter.finished_spans.first }
+
+    it 'has http 200 attributes' do
+      client.get('/success')
+
+      _(span.attributes['component']).must_equal 'http'
+      _(span.attributes['http.method']).must_equal :get
+      _(span.attributes['http.status_code']).must_equal 200
+      _(span.attributes['http.url']).must_equal 'http://example.com/success'
+    end
+
+    it 'has http.status_code 404' do
+      client.get('/not_found')
+
+      _(span.attributes['component']).must_equal 'http'
+      _(span.attributes['http.method']).must_equal :get
+      _(span.attributes['http.status_code']).must_equal 404
+      _(span.attributes['http.url']).must_equal 'http://example.com/not_found'
+    end
+  end
+end

From 5808423c6c01c00bafdb8c3a9caa0f841f753ad8 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Mon, 25 Nov 2019 16:42:38 -0800
Subject: [PATCH 25/32] Add Adapter test

---
 .../adapters/faraday/adapter_test.rb          | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 adapters/faraday/test/opentelemetry/adapters/faraday/adapter_test.rb

diff --git a/adapters/faraday/test/opentelemetry/adapters/faraday/adapter_test.rb b/adapters/faraday/test/opentelemetry/adapters/faraday/adapter_test.rb
new file mode 100644
index 0000000000..62b3159d46
--- /dev/null
+++ b/adapters/faraday/test/opentelemetry/adapters/faraday/adapter_test.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require 'test_helper'
+
+require_relative '../../../../lib/opentelemetry/adapters/faraday/adapter'
+
+describe OpenTelemetry::Adapters::Faraday::Adapter do
+  let(:adapter) { OpenTelemetry::Adapters::Faraday::Adapter }
+
+  before do
+    adapter.install
+  end
+
+  describe 'defaults' do
+    it 'has propagator' do
+      _(adapter.propagator).wont_be_nil
+    end
+
+    it 'has tracer' do
+      _(adapter.tracer).wont_be_nil
+    end
+  end
+end

From 29346a004b52890bc0edb2e9d6556b7eb10cd381 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Wed, 11 Dec 2019 17:41:53 -0800
Subject: [PATCH 26/32] Add/refine tests

---
 .../faraday/middlewares/tracer_middleware_test.rb     | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/adapters/faraday/test/opentelemetry/adapters/faraday/middlewares/tracer_middleware_test.rb b/adapters/faraday/test/opentelemetry/adapters/faraday/middlewares/tracer_middleware_test.rb
index 016e79acfb..71ce35512f 100644
--- a/adapters/faraday/test/opentelemetry/adapters/faraday/middlewares/tracer_middleware_test.rb
+++ b/adapters/faraday/test/opentelemetry/adapters/faraday/middlewares/tracer_middleware_test.rb
@@ -7,7 +7,7 @@
 require 'test_helper'
 
 # require Adapter so .install method is found:
-require_relative '../../../../../lib/opentelemetry/adapters/faraday/adapter'
+require_relative '../../../../../lib/opentelemetry/adapters/faraday'
 require_relative '../../../../../lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware'
 
 describe OpenTelemetry::Adapters::Faraday::Middlewares::TracerMiddleware do
@@ -49,5 +49,14 @@
       _(span.attributes['http.status_code']).must_equal 404
       _(span.attributes['http.url']).must_equal 'http://example.com/not_found'
     end
+
+    it 'has http.status_code 500' do
+      client.get('/failure')
+
+      _(span.attributes['component']).must_equal 'http'
+      _(span.attributes['http.method']).must_equal :get
+      _(span.attributes['http.status_code']).must_equal 500
+      _(span.attributes['http.url']).must_equal 'http://example.com/failure'
+    end
   end
 end

From bc9e87916bbf8a9ac1ea017652fec8ccb7f0e2a4 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Thu, 19 Dec 2019 10:38:29 -0800
Subject: [PATCH 27/32] Allow for easier overriding of TracerMiddleware for
 per-connection rules

* Use case: allow per-connection enabling/disabling of span reporting,
  possibly based on URL rules
---
 adapters/faraday/example/faraday.rb           | 10 +++++++++
 .../opentelemetry/adapters/faraday/adapter.rb |  4 +++-
 .../faraday/middlewares/tracer_middleware.rb  |  8 +++++++
 .../adapters/faraday/patches/rack_builder.rb  |  2 +-
 .../middlewares/tracer_middleware_test.rb     | 21 +++++++++++++++++--
 5 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/adapters/faraday/example/faraday.rb b/adapters/faraday/example/faraday.rb
index c66e96eaeb..c278c65a51 100644
--- a/adapters/faraday/example/faraday.rb
+++ b/adapters/faraday/example/faraday.rb
@@ -15,6 +15,16 @@
   )
 )
 
+# Demonstrate disabling span reporting:
+#
+# require_relative '../lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware'
+# class NoOp < OpenTelemetry::Adapters::Faraday::Middlewares::TracerMiddleware
+#   def disable_span_reporting?(env)
+#     env.url.to_s =~ /example.com/
+#   end
+# end
+# OpenTelemetry::Adapters::Faraday.install(tracer_middleware: NoOp)
+
 OpenTelemetry::Adapters::Faraday.install
 
 conn = Faraday.new('http://example.com')
diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
index 873c60c42e..5bd3dc2d16 100644
--- a/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday/adapter.rb
@@ -20,6 +20,8 @@ class << self
 
           def install(config = {})
             @config = config
+            # allow custom middleware to override default implementation:
+            @config[:tracer_middleware] ||= Middlewares::TracerMiddleware
             @propagator = OpenTelemetry.tracer_factory.http_text_format
 
             new.install
@@ -42,7 +44,7 @@ def install
 
         def register_tracer_middleware
           ::Faraday::Middleware.register_middleware(
-            open_telemetry: Middlewares::TracerMiddleware
+            open_telemetry: self.class.config[:tracer_middleware]
           )
         end
 
diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
index 3c1551d09f..e5499a2ccd 100644
--- a/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday/middlewares/tracer_middleware.rb
@@ -10,6 +10,8 @@ module Faraday
       module Middlewares
         class TracerMiddleware < ::Faraday::Middleware
           def call(env)
+            return app.call(env) if disable_span_reporting?(env)
+
             tracer.in_span(env.url.to_s,
                           attributes: { 'component' => 'http',
                                         'http.method' => env.method,
@@ -21,6 +23,12 @@ def call(env)
             end
           end
 
+          # Override implementation (subclass) to determine per-connection
+          # span reporting rules.
+          def disable_span_reporting?(_env)
+            false
+          end
+
           private
 
           attr_reader :app
diff --git a/adapters/faraday/lib/opentelemetry/adapters/faraday/patches/rack_builder.rb b/adapters/faraday/lib/opentelemetry/adapters/faraday/patches/rack_builder.rb
index 1292ec99a8..65ac6a0938 100644
--- a/adapters/faraday/lib/opentelemetry/adapters/faraday/patches/rack_builder.rb
+++ b/adapters/faraday/lib/opentelemetry/adapters/faraday/patches/rack_builder.rb
@@ -14,7 +14,7 @@ module Patches
         module RackBuilder
           def adapter(*args)
             use(:open_telemetry) unless @handlers.any? do |handler|
-              handler.klass == Middlewares::TracerMiddleware
+              handler.klass == Faraday::Adapter.config[:tracer_middleware]
             end
 
             super
diff --git a/adapters/faraday/test/opentelemetry/adapters/faraday/middlewares/tracer_middleware_test.rb b/adapters/faraday/test/opentelemetry/adapters/faraday/middlewares/tracer_middleware_test.rb
index 71ce35512f..4556e9d6b3 100644
--- a/adapters/faraday/test/opentelemetry/adapters/faraday/middlewares/tracer_middleware_test.rb
+++ b/adapters/faraday/test/opentelemetry/adapters/faraday/middlewares/tracer_middleware_test.rb
@@ -13,6 +13,7 @@
 describe OpenTelemetry::Adapters::Faraday::Middlewares::TracerMiddleware do
   let(:adapter) { OpenTelemetry::Adapters::Faraday }
   let(:exporter) { EXPORTER }
+  let(:span) { exporter.finished_spans.first }
 
   let(:client) do
     ::Faraday.new('http://example.com') do |builder|
@@ -30,8 +31,6 @@
   end
 
   describe 'first span' do
-    let(:span) { exporter.finished_spans.first }
-
     it 'has http 200 attributes' do
       client.get('/success')
 
@@ -59,4 +58,22 @@
       _(span.attributes['http.url']).must_equal 'http://example.com/failure'
     end
   end
+
+  describe 'overriding span reporting' do
+    class NoReportMiddleware < OpenTelemetry::Adapters::Faraday::Middlewares::TracerMiddleware
+      def disable_span_reporting?(_env)
+        true
+      end
+    end
+
+    before do
+      adapter.install(tracer_middleware: NoReportMiddleware)
+    end
+
+    it 'does not report' do
+      client.get('/success')
+
+      _(span).must_be_nil
+    end
+  end
 end

From 73f608650954f2396d3a5f754c98cfc756e268c7 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Thu, 19 Dec 2019 16:11:17 -0800
Subject: [PATCH 28/32] Fix failing circleci builds

* most likely failing due to bundler-2.1.x
* see bundler issue #7489
---
 .circleci/config.yml                                    | 4 +++-
 adapters/faraday/opentelemetry-adapters-faraday.gemspec | 2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index 8d12d84857..b5be588e0f 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -44,7 +44,9 @@ commands:
           name: Bundle + CI (Adapters - Faraday)
           command: |
             cd adapters/faraday
-            gem install --no-document bundler && bundle install --jobs=3 --retry=3
+            gem uninstall -aIx bundler
+            gem install --no-document bundler -v '~> 2.0.2'
+            bundle install --jobs=3 --retry=3
             bundle exec appraisal install
             bundle exec appraisal rake test
   rake-release:
diff --git a/adapters/faraday/opentelemetry-adapters-faraday.gemspec b/adapters/faraday/opentelemetry-adapters-faraday.gemspec
index df4a735e24..02f60aee63 100644
--- a/adapters/faraday/opentelemetry-adapters-faraday.gemspec
+++ b/adapters/faraday/opentelemetry-adapters-faraday.gemspec
@@ -28,7 +28,7 @@ Gem::Specification.new do |spec|
   spec.add_dependency 'opentelemetry-api', '~> 0.0'
 
   spec.add_development_dependency 'appraisal', '~> 2.2.0'
-  spec.add_development_dependency 'bundler', '>= 1.17'
+  spec.add_development_dependency 'bundler', '~> 2.0.2'
   spec.add_development_dependency 'faraday', '~> 0.17.0'
   spec.add_development_dependency 'minitest', '~> 5.0'
   spec.add_development_dependency 'opentelemetry-sdk', '~> 0.0'

From fd66e7d921c5eb8b611def36ac41f817e77f0af3 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Mon, 30 Dec 2019 12:48:51 -0800
Subject: [PATCH 29/32] Fix failing circleci - jruby

* circleci build is failing after jruby:9.2.9-jre
* theory: jruby includes (vendored) its own bundler version
---
 .circleci/config.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index b5be588e0f..91d2cb543b 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -15,7 +15,7 @@ executors:
       - image: "circleci/ruby:2.6-stretch"
   jruby:
     docker:
-      - image: "circleci/jruby:latest"
+      - image: "circleci/jruby:9.2.8-jre"
     environment:
       JRUBY_OPTS: "--debug"
 commands:

From 4098dd4a6430c2b46cc659091260ce3bbeb83655 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Mon, 6 Jan 2020 09:32:00 -0800
Subject: [PATCH 30/32] Appraisal: add faraday-1.0.x

---
 adapters/faraday/Appraisals                   |  4 ++++
 adapters/faraday/gemfiles/faraday_1.0.gemfile | 12 ++++++++++++
 2 files changed, 16 insertions(+)
 create mode 100644 adapters/faraday/gemfiles/faraday_1.0.gemfile

diff --git a/adapters/faraday/Appraisals b/adapters/faraday/Appraisals
index 845f66b1e6..cfb912cb8b 100644
--- a/adapters/faraday/Appraisals
+++ b/adapters/faraday/Appraisals
@@ -1,3 +1,7 @@
+appraise "faraday-1.0" do
+  gem "faraday", "~> 1.0.0"
+end
+
 appraise "faraday-0.17" do
   gem "faraday", "0.17.0"
 end
diff --git a/adapters/faraday/gemfiles/faraday_1.0.gemfile b/adapters/faraday/gemfiles/faraday_1.0.gemfile
new file mode 100644
index 0000000000..cc19b3a9a0
--- /dev/null
+++ b/adapters/faraday/gemfiles/faraday_1.0.gemfile
@@ -0,0 +1,12 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "opentelemetry-api", path: "../../../api"
+gem "faraday", "~> 1.0.0"
+
+group :test do
+  gem "opentelemetry-sdk", path: "../../../sdk"
+end
+
+gemspec path: "../"

From 36cfd8ac7bc264864f1053786ea2d188ad05ece1 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Thu, 9 Jan 2020 10:37:49 -0800
Subject: [PATCH 31/32] circleci: Remove appraisal support, use latest bundler

* TODO: re-enable appraisal support once appraisal issue #162 is solved
---
 .circleci/config.yml                                    | 8 +++-----
 adapters/faraday/opentelemetry-adapters-faraday.gemspec | 2 +-
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index c913180722..d695e1d1eb 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -18,7 +18,7 @@ executors:
       - image: "circleci/ruby:2.7-buster"
   jruby:
     docker:
-      - image: "circleci/jruby:9.2.8-jre"
+      - image: "circleci/jruby:latest"
     environment:
       JRUBY_OPTS: "--debug"
 commands:
@@ -47,11 +47,9 @@ commands:
           name: Bundle + CI (Adapters - Faraday)
           command: |
             cd adapters/faraday
-            gem uninstall -aIx bundler
-            gem install --no-document bundler -v '~> 2.0.2'
+            gem install --no-document bundler
             bundle install --jobs=3 --retry=3
-            bundle exec appraisal install
-            bundle exec appraisal rake test
+            bundle exec rake test
   rake-release:
     steps:
       - checkout
diff --git a/adapters/faraday/opentelemetry-adapters-faraday.gemspec b/adapters/faraday/opentelemetry-adapters-faraday.gemspec
index 02f60aee63..df4a735e24 100644
--- a/adapters/faraday/opentelemetry-adapters-faraday.gemspec
+++ b/adapters/faraday/opentelemetry-adapters-faraday.gemspec
@@ -28,7 +28,7 @@ Gem::Specification.new do |spec|
   spec.add_dependency 'opentelemetry-api', '~> 0.0'
 
   spec.add_development_dependency 'appraisal', '~> 2.2.0'
-  spec.add_development_dependency 'bundler', '~> 2.0.2'
+  spec.add_development_dependency 'bundler', '>= 1.17'
   spec.add_development_dependency 'faraday', '~> 0.17.0'
   spec.add_development_dependency 'minitest', '~> 5.0'
   spec.add_development_dependency 'opentelemetry-sdk', '~> 0.0'

From dc05f823b741110e87d3e42ee619fc4e2dffa504 Mon Sep 17 00:00:00 2001
From: David Davis <david.davis@mutations.ltd>
Date: Thu, 9 Jan 2020 13:49:20 -0800
Subject: [PATCH 32/32] circleci: Workaround failing
 appraisal+bundler(2.1.x)+ruby-2.7 issue

* don't run bundle exec appraisal rake test under ruby-2.7
* NOTE: build was failing under jruby:latest (9.3.x) as well
---
 .circleci/config.yml | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index d695e1d1eb..f4beb9f732 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -21,6 +21,11 @@ executors:
       - image: "circleci/jruby:latest"
     environment:
       JRUBY_OPTS: "--debug"
+  jruby92:
+    docker:
+      - image: "circleci/jruby:9.2.8-jre"
+    environment:
+      JRUBY_OPTS: "--debug"
 commands:
   rake-test:
     steps:
@@ -43,13 +48,17 @@ commands:
       - run:
           name: CI (Jaeger)
           command: "cd exporters/jaeger && bundle exec rake"
+  rake-test-appraisal:
+    steps:
       - run:
           name: Bundle + CI (Adapters - Faraday)
           command: |
             cd adapters/faraday
-            gem install --no-document bundler
+            gem uninstall -aIx bundler
+            gem install --no-document bundler -v '~> 2.0.2'
             bundle install --jobs=3 --retry=3
-            bundle exec rake test
+            bundle exec appraisal install
+            bundle exec appraisal rake test
   rake-release:
     steps:
       - checkout
@@ -64,14 +73,17 @@ jobs:
     executor: ruby24
     steps:
       - rake-test
+      - rake-test-appraisal
   test-ruby25:
     executor: ruby25
     steps:
       - rake-test
+      - rake-test-appraisal
   test-ruby26:
     executor: ruby26
     steps:
       - rake-test
+      - rake-test-appraisal
   test-ruby27:
     executor: ruby27
     steps:
@@ -80,10 +92,16 @@ jobs:
     executor: jruby
     steps:
       - rake-test
+  test-jruby92:
+    executor: jruby92
+    steps:
+      - rake-test
+      - rake-test-appraisal
   release:
     executor: ruby26
     steps:
       - rake-release
+      - rake-test-appraisal
 workflows:
   version: 2
   builds:
@@ -108,6 +126,10 @@ workflows:
           filters:
             tags:
               only: /^opentelemetry-.+\/v\d.*$/
+      - test-jruby92:
+          filters:
+            tags:
+              only: /^opentelemetry-.+\/v\d.*$/
       - release:
           requires:
             - test-ruby24