Initial contribution of remote tap extension (open-telemetry#27477)

**Description:**
Adds the basis of a new extension, the remote ~observer~ tap extension,
to be used to display the contents of the data observed via remote
observer processors.

This PR deals only with the structure and required files related to the
extension.

**Link to tracking Issue:**
open-telemetry#19634

**Testing:**
N/A

**Documentation:**
README

---------

Co-authored-by: Pablo Collins <[email protected]>

.chloggen/new_extension_remotetap.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: new_component
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: remotetapextension
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add a new extension, remotetapextension to use with the remoteobserverprocessor processors.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [19634]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

.github/CODEOWNERS

@@ -111,6 +111,7 @@ extension/observer/k8sobserver/                                         @open-te
 extension/oidcauthextension/                                            @open-telemetry/collector-contrib-approvers @jpkrohling
 extension/opampextension/                                               @open-telemetry/collector-contrib-approvers @portertech @evan-bradley @tigrannajaryan
 extension/pprofextension/                                               @open-telemetry/collector-contrib-approvers @MovieStoreGuy
+extension/remotetapextension/                                           @open-telemetry/collector-contrib-approvers @atoulme
 extension/sigv4authextension/                                           @open-telemetry/collector-contrib-approvers @Aneurysm9 @erichsueh3
 extension/storage/                                                      @open-telemetry/collector-contrib-approvers @dmitryax @atoulme @djaglowski
 extension/storage/dbstorage/                                            @open-telemetry/collector-contrib-approvers @dmitryax @atoulme

.github/ISSUE_TEMPLATE/bug_report.yaml

@@ -103,6 +103,7 @@ body:
       - extension/oidcauth
       - extension/opamp
       - extension/pprof
+      - extension/remotetap
       - extension/sigv4auth
       - extension/storage
       - extension/storage/dbstorage

.github/ISSUE_TEMPLATE/feature_request.yaml

@@ -97,6 +97,7 @@ body:
       - extension/oidcauth
       - extension/opamp
       - extension/pprof
+      - extension/remotetap
       - extension/sigv4auth
       - extension/storage
       - extension/storage/dbstorage

.github/ISSUE_TEMPLATE/other.yaml

@@ -97,6 +97,7 @@ body:
       - extension/oidcauth
       - extension/opamp
       - extension/pprof
+      - extension/remotetap
       - extension/sigv4auth
       - extension/storage
       - extension/storage/dbstorage

.github/dependabot.yml

@@ -7,11 +7,6 @@ updates:
     schedule:
       interval: "weekly"
       day: "wednesday"
-  - package-ecosystem: "gomod"
-    directory: "/cmd/telemetrygen"
-    schedule:
-      interval: "weekly"
-      day: "wednesday"
   - package-ecosystem: "gomod"
     directory: "/confmap/provider/s3provider"
     schedule:
@@ -297,6 +292,16 @@ updates:
     schedule:
       interval: "weekly"
       day: "wednesday"
+  - package-ecosystem: "gomod"
+    directory: "/extension/encoding/jsonlogencodingextension"
+    schedule:
+      interval: "weekly"
+      day: "wednesday"
+  - package-ecosystem: "gomod"
+    directory: "/extension/encoding/otlpencodingextension"
+    schedule:
+      interval: "weekly"
+      day: "wednesday"
   - package-ecosystem: "gomod"
     directory: "/extension/headerssetterextension"
     schedule:
@@ -357,11 +362,6 @@ updates:
     schedule:
       interval: "weekly"
       day: "wednesday"
-  - package-ecosystem: "gomod"
-    directory: "/extension/opampextension"
-    schedule:
-      interval: "weekly"
-      day: "wednesday"
   - package-ecosystem: "gomod"
     directory: "/extension/pprofextension"
     schedule:

extension/remotetapextension/Makefile

@@ -0,0 +1 @@
+include ../../Makefile.Common

extension/remotetapextension/README.md

@@ -0,0 +1,31 @@
+# Remote Tap Extension
+
+<!-- status autogenerated section -->
+| Status        |           |
+| ------------- |-----------|
+| Stability     | [development]  |
+| Distributions | [] |
+| Issues        | [![Open issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aopen%20label%3Aextension%2Fremotetap%20&label=open&color=orange&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aopen+is%3Aissue+label%3Aextension%2Fremotetap) [![Closed issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aclosed%20label%3Aextension%2Fremotetap%20&label=closed&color=blue&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aclosed+is%3Aissue+label%3Aextension%2Fremotetap) |
+| [Code Owners](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/CONTRIBUTING.md#becoming-a-code-owner)    | [@atoulme](https://www.github.com/atoulme) |
+
+[development]: https://github.com/open-telemetry/opentelemetry-collector#development
+<!-- end autogenerated section -->
+
+This extension runs as a Web server that loads the remote observers that are registered against it.
+
+It allows users of the collectors to visualize data going through pipelines.
+
+The following settings are required:
+
+- `endpoint` (default = localhost:11000): The endpoint in which the web server will
+be listening to. Use localhost:<port> to make it available only locally, or
+":<port>" to make it available on all network interfaces.
+
+Example:
+```yaml
+
+extensions:
+  remoteobserver:
+```
+
+The full list of settings exposed for this exporter are documented [here](./config.go).

extension/remotetapextension/config.go

@@ -0,0 +1,21 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package remotetapextension // import "github.com/open-telemetry/opentelemetry-collector-contrib/extension/remotetapextension"
+
+import (
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config/confighttp"
+)
+
+type Config struct {
+	confighttp.HTTPServerSettings `mapstructure:",squash"` // squash ensures fields are correctly decoded in embedded struct
+}
+
+func createDefaultConfig() component.Config {
+	return &Config{
+		HTTPServerSettings: confighttp.HTTPServerSettings{
+			Endpoint: "127.0.0.1:11000",
+		},
+	}
+}

extension/remotetapextension/doc.go

@@ -0,0 +1,8 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+//go:generate mdatagen metadata.yaml
+
+// Package remotetapextension implements an extension that exposes the golang
+// remoteobserver processor websockets through a Web interface.
+package remotetapextension // import "github.com/open-telemetry/opentelemetry-collector-contrib/extension/remotetapextension"

extension/remotetapextension/extension.go

@@ -0,0 +1,53 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package remotetapextension // import "github.com/open-telemetry/opentelemetry-collector-contrib/extension/remotetapextension"
+
+import (
+	"context"
+	"embed"
+	"errors"
+	"io/fs"
+	"net/http"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/extension"
+)
+
+//go:embed http/*
+var httpFS embed.FS
+
+type remoteObserverExtension struct {
+	config   *Config
+	settings extension.CreateSettings
+	server   *http.Server
+}
+
+func (s *remoteObserverExtension) Start(_ context.Context, host component.Host) error {
+
+	htmlContent, err := fs.Sub(httpFS, "html")
+	if err != nil {
+		return err
+	}
+	mux := http.NewServeMux()
+	mux.Handle("/", http.FileServer(http.FS(htmlContent)))
+	s.server, err = s.config.HTTPServerSettings.ToServer(host, s.settings.TelemetrySettings, mux)
+	if err != nil {
+		return err
+	}
+
+	go func() {
+		err := s.server.ListenAndServe()
+		if err != nil && !errors.Is(err, http.ErrServerClosed) {
+			_ = s.settings.TelemetrySettings.ReportComponentStatus(component.NewFatalErrorEvent(err))
+		}
+	}()
+	return nil
+}
+
+func (s *remoteObserverExtension) Shutdown(_ context.Context) error {
+	if s.server == nil {
+		return nil
+	}
+	return s.server.Close()
+}

extension/remotetapextension/factory.go

@@ -0,0 +1,26 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package remotetapextension // import "github.com/open-telemetry/opentelemetry-collector-contrib/extension/remotetapextension"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/extension"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/extension/remotetapextension/internal/metadata"
+)
+
+func NewFactory() extension.Factory {
+	return extension.NewFactory(
+		metadata.Type,
+		createDefaultConfig,
+		createExtension,
+		component.StabilityLevelDevelopment,
+	)
+}
+
+func createExtension(_ context.Context, settings extension.CreateSettings, config component.Config) (extension.Extension, error) {
+	return &remoteObserverExtension{config: config.(*Config), settings: settings}, nil
+}

extension/remotetapextension/go.mod

@@ -0,0 +1,50 @@
+module github.com/open-telemetry/opentelemetry-collector-contrib/extension/remotetapextension
+
+go 1.20
+
+require (
+	go.opentelemetry.io/collector/component v0.88.1-0.20231026220224-6405e152a2d9
+	go.opentelemetry.io/collector/config/confighttp v0.88.1-0.20231026220224-6405e152a2d9
+	go.opentelemetry.io/collector/extension v0.88.1-0.20231026220224-6405e152a2d9
+)
+
+require (
+	github.com/felixge/httpsnoop v1.0.3 // indirect
+	github.com/fsnotify/fsnotify v1.7.0 // indirect
+	github.com/go-logr/logr v1.2.4 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/protobuf v1.5.3 // indirect
+	github.com/golang/snappy v0.0.4 // indirect
+	github.com/klauspost/compress v1.17.2 // indirect
+	github.com/knadh/koanf/maps v0.1.1 // indirect
+	github.com/knadh/koanf/providers/confmap v0.1.0 // indirect
+	github.com/knadh/koanf/v2 v2.0.1 // indirect
+	github.com/mitchellh/copystructure v1.2.0 // indirect
+	github.com/mitchellh/mapstructure v1.5.1-0.20220423185008-bf980b35cac4 // indirect
+	github.com/mitchellh/reflectwalk v1.0.2 // indirect
+	github.com/rs/cors v1.10.1 // indirect
+	go.opentelemetry.io/collector v0.88.1-0.20231026220224-6405e152a2d9 // indirect
+	go.opentelemetry.io/collector/config/configauth v0.88.1-0.20231026220224-6405e152a2d9 // indirect
+	go.opentelemetry.io/collector/config/configcompression v0.88.1-0.20231026220224-6405e152a2d9 // indirect
+	go.opentelemetry.io/collector/config/configopaque v0.88.1-0.20231026220224-6405e152a2d9 // indirect
+	go.opentelemetry.io/collector/config/configtelemetry v0.88.1-0.20231026220224-6405e152a2d9 // indirect
+	go.opentelemetry.io/collector/config/configtls v0.88.1-0.20231026220224-6405e152a2d9 // indirect
+	go.opentelemetry.io/collector/config/internal v0.88.1-0.20231026220224-6405e152a2d9 // indirect
+	go.opentelemetry.io/collector/confmap v0.88.1-0.20231026220224-6405e152a2d9 // indirect
+	go.opentelemetry.io/collector/extension/auth v0.88.1-0.20231026220224-6405e152a2d9 // indirect
+	go.opentelemetry.io/collector/featuregate v1.0.0-rcv0017.0.20231026220224-6405e152a2d9 // indirect
+	go.opentelemetry.io/collector/pdata v1.0.0-rcv0017.0.20231026220224-6405e152a2d9 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.45.0 // indirect
+	go.opentelemetry.io/otel v1.19.0 // indirect
+	go.opentelemetry.io/otel/metric v1.19.0 // indirect
+	go.opentelemetry.io/otel/trace v1.19.0 // indirect
+	go.uber.org/multierr v1.11.0 // indirect
+	go.uber.org/zap v1.26.0 // indirect
+	golang.org/x/net v0.17.0 // indirect
+	golang.org/x/sys v0.13.0 // indirect
+	golang.org/x/text v0.13.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20230822172742-b8732ec3820d // indirect
+	google.golang.org/grpc v1.59.0 // indirect
+	google.golang.org/protobuf v1.31.0 // indirect
+)