From dff68bbd40b21a73e946f7f037f177dc75047c1f Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Thu, 13 Jun 2019 14:24:03 -0700
Subject: [PATCH 01/12] Add initial span interface

---
 packages/opentelemetry-types/src/index.ts     |   5 +
 .../opentelemetry-types/src/trace/span.ts     | 105 ++++++++++++
 .../src/trace/span_context.ts                 |  30 ++++
 .../src/trace/span_kind.ts                    |  50 ++++++
 .../opentelemetry-types/src/trace/status.ts   | 161 ++++++++++++++++++
 5 files changed, 351 insertions(+)
 create mode 100644 packages/opentelemetry-types/src/trace/span.ts
 create mode 100644 packages/opentelemetry-types/src/trace/span_context.ts
 create mode 100644 packages/opentelemetry-types/src/trace/span_kind.ts
 create mode 100644 packages/opentelemetry-types/src/trace/status.ts

diff --git a/packages/opentelemetry-types/src/index.ts b/packages/opentelemetry-types/src/index.ts
index 62fb100a20..99e37437e9 100644
--- a/packages/opentelemetry-types/src/index.ts
+++ b/packages/opentelemetry-types/src/index.ts
@@ -13,3 +13,8 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+export * from './trace/span';
+export * from './trace/span_context';
+export * from './trace/span_kind';
+export * from './trace/status';
diff --git a/packages/opentelemetry-types/src/trace/span.ts b/packages/opentelemetry-types/src/trace/span.ts
new file mode 100644
index 0000000000..8f438b5199
--- /dev/null
+++ b/packages/opentelemetry-types/src/trace/span.ts
@@ -0,0 +1,105 @@
+/**
+ * Copyright 2019, OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { SpanContext } from './span_context';
+import { Status } from './status';
+
+/**
+ * An interface that represents a span. A span represents a single operation
+ * within a trace. Examples of span might include remote procedure calls or a
+ * in-process function calls to sub-components. A Trace has a single, top-level
+ * "root" Span that in turn may have zero or more child Spans, which in turn
+ * may have children.
+ */
+export interface Span {
+  /**
+   * Returns the SpanContext object associated with this Span.
+   *
+   * @returns the SpanContext object associated with this Span.
+   */
+  context(): SpanContext;
+
+  // /**
+  //  * # TODO
+  //  * Returns the Tracer object used to create this Span.
+  //  * https://github.com/open-telemetry/opentelemetry-specification/issues/21
+  //  */
+  // tracer(): Tracer;
+
+  /**
+   * Sets an attribute to the span.
+   *
+   * @param key the key for this attribute.
+   * @param value the value for this attribute.
+   */
+  setAttribute(key: string, value: string | number | boolean | object): void;
+
+  /**
+   * Adds an event to the Span.
+   *
+   * @param name the name of the event.
+   * @param [attributes] the attributes that will be added; these are
+   *     associated with this event.
+   */
+  addEvent(
+    name: string,
+    attributes?: { [key: string]: string | number | boolean }
+  ): void;
+
+  /**
+   * Adds a link to the Span.
+   *
+   * @param spanContext the context of the linked span.
+   * @param [attributes] the attributes that will be added; these are
+   *     associated with this link.
+   */
+  addLink(
+    spanContext: SpanContext,
+    attributes?: { [key: string]: string | number | boolean }
+  ): void;
+
+  /**
+   * Sets a status to the span. If used, this will override the default Span
+   * status. Default is 'OK'.
+   *
+   * @param status the Status to set.
+   */
+  setStatus(status: Status): void;
+
+  /**
+   * Updates the Span name.
+   *
+   * @param name the Span name.
+   */
+  updateName(name: string): void;
+
+  /**
+   * Marks the end of Span execution and sets the current time as the span's
+   * end time.
+   *
+   * Call to End of a Span MUST not have any effects on child spans. Those may
+   * still be running and can be ended later.
+   */
+  end(): void;
+
+  /**
+   * Returns the flag whether this span will be recorded.
+   *
+   * @returns true if this Span is active and recording information like events
+   * with the AddEvent operation and attributes using setAttributes.
+   */
+  isRecordingEvents(): boolean;
+}
diff --git a/packages/opentelemetry-types/src/trace/span_context.ts b/packages/opentelemetry-types/src/trace/span_context.ts
new file mode 100644
index 0000000000..474b9a9513
--- /dev/null
+++ b/packages/opentelemetry-types/src/trace/span_context.ts
@@ -0,0 +1,30 @@
+/**
+ * Copyright 2019, OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * A SpanContext represents the portion of a Span which must be serialized and
+ * propagated along side of a distributed context.
+ */
+export interface SpanContext {
+  /** The ID of the trace that this span belongs to. */
+  traceId: string;
+  /** The ID of the Span. */
+  spanId: string;
+  /** Trace options to propagate. */
+  traceOptions?: number;
+  /** Tracing-system-specific info to propagate. */
+  traceState?: string;
+}
diff --git a/packages/opentelemetry-types/src/trace/span_kind.ts b/packages/opentelemetry-types/src/trace/span_kind.ts
new file mode 100644
index 0000000000..688650f2be
--- /dev/null
+++ b/packages/opentelemetry-types/src/trace/span_kind.ts
@@ -0,0 +1,50 @@
+/**
+ * Copyright 2019, OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Type of span. Can be used to specify additional relationships between spans
+ * in addition to a parent/child relationship.
+ */
+export enum SpanKind {
+  /** Default value. Indicates that the span is used internally. */
+  INTERNAL = 0,
+
+  /**
+   * Indicates that the span covers server-side handling of an RPC or other
+   * remote request.
+   */
+  SERVER = 1,
+
+  /**
+   * Indicates that the span covers the client-side wrapper around an RPC or
+   * other remote request.
+   */
+  CLIENT = 2,
+
+  /**
+   * Indicates that the span describes producer sending a message to a
+   * broker. Unlike client and server, there is no direct critical path latency
+   * relationship between producer and consumer spans.
+   */
+  PRODUCER = 3,
+
+  /**
+   * Indicates that the span describes consumer receiving a message from a
+   * broker. Unlike client and server, there is no direct critical path latency
+   * relationship between producer and consumer spans.
+   */
+  CONSUMER = 4,
+}
diff --git a/packages/opentelemetry-types/src/trace/status.ts b/packages/opentelemetry-types/src/trace/status.ts
new file mode 100644
index 0000000000..e34dbf4cc9
--- /dev/null
+++ b/packages/opentelemetry-types/src/trace/status.ts
@@ -0,0 +1,161 @@
+/**
+ * Copyright 2019, OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * The status of a Span by providing a standard CanonicalCode in conjunction
+ * with an optional descriptive message.
+ */
+export interface Status {
+  /** The canonical code of this message. */
+  code: CanonicalCode;
+  /** A developer-facing error message. */
+  message?: string;
+}
+
+/** An enumeration of canonical status codes. */
+export enum CanonicalCode {
+  /**
+   * Not an error; returned on success
+   */
+  OK = 0,
+  /**
+   * The operation was cancelled (typically by the caller).
+   */
+  CANCELLED = 1,
+  /**
+   * Unknown error.  An example of where this error may be returned is
+   * if a status value received from another address space belongs to
+   * an error-space that is not known in this address space.  Also
+   * errors raised by APIs that do not return enough error information
+   * may be converted to this error.
+   */
+  UNKNOWN = 2,
+  /**
+   * Client specified an invalid argument.  Note that this differs
+   * from FAILED_PRECONDITION.  INVALID_ARGUMENT indicates arguments
+   * that are problematic regardless of the state of the system
+   * (e.g., a malformed file name).
+   */
+  INVALID_ARGUMENT = 3,
+  /**
+   * Deadline expired before operation could complete.  For operations
+   * that change the state of the system, this error may be returned
+   * even if the operation has completed successfully.  For example, a
+   * successful response from a server could have been delayed long
+   * enough for the deadline to expire.
+   */
+  DEADLINE_EXCEEDED = 4,
+  /**
+   * Some requested entity (e.g., file or directory) was not found.
+   */
+  NOT_FOUND = 5,
+  /**
+   * Some entity that we attempted to create (e.g., file or directory)
+   * already exists.
+   */
+  ALREADY_EXISTS = 6,
+  /**
+   * The caller does not have permission to execute the specified
+   * operation.  PERMISSION_DENIED must not be used for rejections
+   * caused by exhausting some resource (use RESOURCE_EXHAUSTED
+   * instead for those errors).  PERMISSION_DENIED must not be
+   * used if the caller can not be identified (use UNAUTHENTICATED
+   * instead for those errors).
+   */
+  PERMISSION_DENIED = 7,
+  /**
+   * Some resource has been exhausted, perhaps a per-user quota, or
+   * perhaps the entire file system is out of space.
+   */
+  RESOURCE_EXHAUSTED = 8,
+  /**
+   * Operation was rejected because the system is not in a state
+   * required for the operation's execution.  For example, directory
+   * to be deleted may be non-empty, an rmdir operation is applied to
+   * a non-directory, etc.
+   *
+   * A litmus test that may help a service implementor in deciding
+   * between FAILED_PRECONDITION, ABORTED, and UNAVAILABLE:
+   *
+   *  - Use UNAVAILABLE if the client can retry just the failing call.
+   *  - Use ABORTED if the client should retry at a higher-level
+   *    (e.g., restarting a read-modify-write sequence).
+   *  - Use FAILED_PRECONDITION if the client should not retry until
+   *    the system state has been explicitly fixed.  E.g., if an "rmdir"
+   *    fails because the directory is non-empty, FAILED_PRECONDITION
+   *    should be returned since the client should not retry unless
+   *    they have first fixed up the directory by deleting files from it.
+   *  - Use FAILED_PRECONDITION if the client performs conditional
+   *    REST Get/Update/Delete on a resource and the resource on the
+   *    server does not match the condition. E.g., conflicting
+   *    read-modify-write on the same resource.
+   */
+  FAILED_PRECONDITION = 9,
+  /**
+   * The operation was aborted, typically due to a concurrency issue
+   * like sequencer check failures, transaction aborts, etc.
+   *
+   * See litmus test above for deciding between FAILED_PRECONDITION,
+   * ABORTED, and UNAVAILABLE.
+   */
+  ABORTED = 10,
+  /**
+   * Operation was attempted past the valid range.  E.g., seeking or
+   * reading past end of file.
+   *
+   * Unlike INVALID_ARGUMENT, this error indicates a problem that may
+   * be fixed if the system state changes. For example, a 32-bit file
+   * system will generate INVALID_ARGUMENT if asked to read at an
+   * offset that is not in the range [0,2^32-1], but it will generate
+   * OUT_OF_RANGE if asked to read from an offset past the current
+   * file size.
+   *
+   * There is a fair bit of overlap between FAILED_PRECONDITION and
+   * OUT_OF_RANGE.  We recommend using OUT_OF_RANGE (the more specific
+   * error) when it applies so that callers who are iterating through
+   * a space can easily look for an OUT_OF_RANGE error to detect when
+   * they are done.
+   */
+  OUT_OF_RANGE = 11,
+  /**
+   * Operation is not implemented or not supported/enabled in this service.
+   */
+  UNIMPLEMENTED = 12,
+  /**
+   * Internal errors.  Means some invariants expected by underlying
+   * system has been broken.  If you see one of these errors,
+   * something is very broken.
+   */
+  INTERNAL = 13,
+  /**
+   * The service is currently unavailable.  This is a most likely a
+   * transient condition and may be corrected by retrying with
+   * a backoff.
+   *
+   * See litmus test above for deciding between FAILED_PRECONDITION,
+   * ABORTED, and UNAVAILABLE.
+   */
+  UNAVAILABLE = 14,
+  /**
+   * Unrecoverable data loss or corruption.
+   */
+  DATA_LOSS = 15,
+  /**
+   * The request does not have valid authentication credentials for the
+   * operation.
+   */
+  UNAUTHENTICATED = 16,
+}

From 231109577478d57e5b6de9526718946c4711e6ca Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Thu, 13 Jun 2019 21:04:56 -0700
Subject: [PATCH 02/12] Add object type attribute

---
 packages/opentelemetry-types/src/trace/span.ts | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/packages/opentelemetry-types/src/trace/span.ts b/packages/opentelemetry-types/src/trace/span.ts
index 8f438b5199..1fecd97ac3 100644
--- a/packages/opentelemetry-types/src/trace/span.ts
+++ b/packages/opentelemetry-types/src/trace/span.ts
@@ -43,7 +43,8 @@ export interface Span {
    * Sets an attribute to the span.
    *
    * @param key the key for this attribute.
-   * @param value the value for this attribute.
+   * @param value the value for this attribute. If the value is a typeof object
+   *     it has to be JSON.stringify-able otherwise it will raise an exception.
    */
   setAttribute(key: string, value: string | number | boolean | object): void;
 
@@ -56,7 +57,7 @@ export interface Span {
    */
   addEvent(
     name: string,
-    attributes?: { [key: string]: string | number | boolean }
+    attributes?: { [key: string]: string | number | boolean | object }
   ): void;
 
   /**
@@ -68,7 +69,7 @@ export interface Span {
    */
   addLink(
     spanContext: SpanContext,
-    attributes?: { [key: string]: string | number | boolean }
+    attributes?: { [key: string]: string | number | boolean | object }
   ): void;
 
   /**

From fafce9fdcfa776be42479dab2402bbbe00cd14f9 Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Fri, 14 Jun 2019 10:47:57 -0700
Subject: [PATCH 03/12] return this and add optional endTime

---
 .../opentelemetry-types/src/trace/span.ts     | 24 +++++++++++--------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/packages/opentelemetry-types/src/trace/span.ts b/packages/opentelemetry-types/src/trace/span.ts
index 1fecd97ac3..c3a4bccc8d 100644
--- a/packages/opentelemetry-types/src/trace/span.ts
+++ b/packages/opentelemetry-types/src/trace/span.ts
@@ -43,10 +43,9 @@ export interface Span {
    * Sets an attribute to the span.
    *
    * @param key the key for this attribute.
-   * @param value the value for this attribute. If the value is a typeof object
-   *     it has to be JSON.stringify-able otherwise it will raise an exception.
+   * @param value the value for this attribute.
    */
-  setAttribute(key: string, value: string | number | boolean | object): void;
+  setAttribute(key: string, value: string | number | boolean | object): this;
 
   /**
    * Adds an event to the Span.
@@ -58,7 +57,7 @@ export interface Span {
   addEvent(
     name: string,
     attributes?: { [key: string]: string | number | boolean | object }
-  ): void;
+  ): this;
 
   /**
    * Adds a link to the Span.
@@ -70,7 +69,7 @@ export interface Span {
   addLink(
     spanContext: SpanContext,
     attributes?: { [key: string]: string | number | boolean | object }
-  ): void;
+  ): this;
 
   /**
    * Sets a status to the span. If used, this will override the default Span
@@ -78,23 +77,28 @@ export interface Span {
    *
    * @param status the Status to set.
    */
-  setStatus(status: Status): void;
+  setStatus(status: Status): this;
 
   /**
    * Updates the Span name.
    *
    * @param name the Span name.
    */
-  updateName(name: string): void;
+  updateName(name: string): this;
 
   /**
-   * Marks the end of Span execution and sets the current time as the span's
-   * end time.
+   * Marks the end of Span execution.
    *
    * Call to End of a Span MUST not have any effects on child spans. Those may
    * still be running and can be ended later.
+   *
+   * Do not return `this`. The Span generally should not be used after it
+   * is ended so chaining is not desired in this context.
+   *
+   * @param [endTime] the timestamp to set as Span's end time. If not provided,
+   *     use the current time as the span's end time.
    */
-  end(): void;
+  end(endTime?: number): void;
 
   /**
    * Returns the flag whether this span will be recorded.

From db13c94a38c96bbf9ec0ed8e12e88ee7804da545 Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Fri, 14 Jun 2019 14:19:31 -0700
Subject: [PATCH 04/12] Use any and add TODO

---
 packages/opentelemetry-types/src/trace/span.ts | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/packages/opentelemetry-types/src/trace/span.ts b/packages/opentelemetry-types/src/trace/span.ts
index c3a4bccc8d..4e79217cae 100644
--- a/packages/opentelemetry-types/src/trace/span.ts
+++ b/packages/opentelemetry-types/src/trace/span.ts
@@ -45,7 +45,8 @@ export interface Span {
    * @param key the key for this attribute.
    * @param value the value for this attribute.
    */
-  setAttribute(key: string, value: string | number | boolean | object): this;
+  //tslint:disable-next-line:no-any
+  setAttribute(key: string, value: any): this;
 
   /**
    * Adds an event to the Span.
@@ -54,10 +55,8 @@ export interface Span {
    * @param [attributes] the attributes that will be added; these are
    *     associated with this event.
    */
-  addEvent(
-    name: string,
-    attributes?: { [key: string]: string | number | boolean | object }
-  ): this;
+  //tslint:disable-next-line:no-any
+  addEvent(name: string, attributes?: { [key: string]: any }): this;
 
   /**
    * Adds a link to the Span.
@@ -66,10 +65,8 @@ export interface Span {
    * @param [attributes] the attributes that will be added; these are
    *     associated with this link.
    */
-  addLink(
-    spanContext: SpanContext,
-    attributes?: { [key: string]: string | number | boolean | object }
-  ): this;
+  //tslint:disable-next-line:no-any
+  addLink(spanContext: SpanContext, attributes?: { [key: string]: any }): this;
 
   /**
    * Sets a status to the span. If used, this will override the default Span
@@ -82,6 +79,8 @@ export interface Span {
   /**
    * Updates the Span name.
    *
+   * TODO (revision): https://github.com/open-telemetry/opentelemetry-specification/issues/119
+   *
    * @param name the Span name.
    */
   updateName(name: string): this;

From 52e53abd9d8e93f470bcba66db47d3edf39fe242 Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Fri, 14 Jun 2019 15:23:57 -0700
Subject: [PATCH 05/12] Update TraceState with examples and add TODO

---
 .../src/trace/span_context.ts                 | 25 +++++++++++++++++--
 .../opentelemetry-types/src/trace/status.ts   |  6 ++++-
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/packages/opentelemetry-types/src/trace/span_context.ts b/packages/opentelemetry-types/src/trace/span_context.ts
index 474b9a9513..e136f74b01 100644
--- a/packages/opentelemetry-types/src/trace/span_context.ts
+++ b/packages/opentelemetry-types/src/trace/span_context.ts
@@ -23,8 +23,29 @@ export interface SpanContext {
   traceId: string;
   /** The ID of the Span. */
   spanId: string;
-  /** Trace options to propagate. */
+  /**
+   * Trace options to propagate.
+   *
+   * It is represented as 1 byte (bitmap). Bit to represent whether trace is
+   * sampled or not.
+   * SAMPLED_VALUE = 0x1 and NOT_SAMPLED_VALUE = 0x0;
+   */
   traceOptions?: number;
-  /** Tracing-system-specific info to propagate. */
+  /**
+   * Tracing-system-specific info to propagate.
+   *
+   * The tracestate field value is a `list` as defined below. The `list` is a
+   * series of `list-members` separated by commas `,`, and a list-member is a
+   * key/value pair separated by an equals sign `=`. Spaces and horizontal tabs
+   * surrounding `list-members` are ignored. There can be a maximum of 32
+   * `list-members` in a `list`.
+   * More Info: https://www.w3.org/TR/trace-context/#tracestate-field
+   *
+   * Examples:
+   *     Single tracing system (generic format):
+   *         tracestate: rojo=00f067aa0ba902b7
+   *     Multiple tracing systems (with different formatting):
+   *         tracestate: rojo=00f067aa0ba902b7,congo=t61rcWkgMzE
+   */
   traceState?: string;
 }
diff --git a/packages/opentelemetry-types/src/trace/status.ts b/packages/opentelemetry-types/src/trace/status.ts
index e34dbf4cc9..be84093ce1 100644
--- a/packages/opentelemetry-types/src/trace/status.ts
+++ b/packages/opentelemetry-types/src/trace/status.ts
@@ -25,7 +25,11 @@ export interface Status {
   message?: string;
 }
 
-/** An enumeration of canonical status codes. */
+/**
+ * An enumeration of canonical status codes.
+ *
+ * TODO (revision): https://github.com/open-telemetry/opentelemetry-specification/issues/59
+ */
 export enum CanonicalCode {
   /**
    * Not an error; returned on success

From 424c9fde98a16f69f6893f6e5550695be2c9cb32 Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Sun, 16 Jun 2019 23:02:52 -0700
Subject: [PATCH 06/12] specify traceId and spanId format

---
 .../opentelemetry-types/src/trace/span_context.ts   | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/packages/opentelemetry-types/src/trace/span_context.ts b/packages/opentelemetry-types/src/trace/span_context.ts
index e136f74b01..f2a183aa90 100644
--- a/packages/opentelemetry-types/src/trace/span_context.ts
+++ b/packages/opentelemetry-types/src/trace/span_context.ts
@@ -19,9 +19,18 @@
  * propagated along side of a distributed context.
  */
 export interface SpanContext {
-  /** The ID of the trace that this span belongs to. */
+  /**
+   * The ID of the trace that this span belongs to. It is worldwide unique
+   * with practically sufficient probability by being made as 16 randomly
+   * generated bytes, encoded as a 32 lowercase hex characters corresponding to
+   * 128 bits.
+   */
   traceId: string;
-  /** The ID of the Span. */
+  /**
+   * The ID of the Span. It is globally unique with practically sufficient
+   * probability by being made as 8 randomly generated bytes, encoded as a 16
+   * lowercase hex characters corresponding to 64 bits.
+   */
   spanId: string;
   /**
    * Trace options to propagate.

From d969247a07cc2f0d8652209fc4c83a530684879e Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Mon, 17 Jun 2019 10:22:25 -0700
Subject: [PATCH 07/12] use unknown instead of any

---
 packages/opentelemetry-types/src/trace/span.ts | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/packages/opentelemetry-types/src/trace/span.ts b/packages/opentelemetry-types/src/trace/span.ts
index 4e79217cae..9f2188266c 100644
--- a/packages/opentelemetry-types/src/trace/span.ts
+++ b/packages/opentelemetry-types/src/trace/span.ts
@@ -45,8 +45,7 @@ export interface Span {
    * @param key the key for this attribute.
    * @param value the value for this attribute.
    */
-  //tslint:disable-next-line:no-any
-  setAttribute(key: string, value: any): this;
+  setAttribute(key: string, value: unknown): this;
 
   /**
    * Adds an event to the Span.
@@ -55,8 +54,7 @@ export interface Span {
    * @param [attributes] the attributes that will be added; these are
    *     associated with this event.
    */
-  //tslint:disable-next-line:no-any
-  addEvent(name: string, attributes?: { [key: string]: any }): this;
+  addEvent(name: string, attributes?: { [key: string]: unknown }): this;
 
   /**
    * Adds a link to the Span.
@@ -65,8 +63,7 @@ export interface Span {
    * @param [attributes] the attributes that will be added; these are
    *     associated with this link.
    */
-  //tslint:disable-next-line:no-any
-  addLink(spanContext: SpanContext, attributes?: { [key: string]: any }): this;
+  addLink(spanContext: SpanContext, attributes?: { [key: string]: unknown }): this;
 
   /**
    * Sets a status to the span. If used, this will override the default Span

From 01d1340a0ada291b60970a8abe8927a463b6a898 Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Mon, 17 Jun 2019 17:08:54 -0700
Subject: [PATCH 08/12] Add TraceOptions and TraceState empty class

---
 .../src/trace/span_context.ts                 |  7 +++++--
 .../src/trace/traceoptions.ts                 | 19 +++++++++++++++++++
 .../src/trace/tracestate.ts                   | 19 +++++++++++++++++++
 3 files changed, 43 insertions(+), 2 deletions(-)
 create mode 100644 packages/opentelemetry-types/src/trace/traceoptions.ts
 create mode 100644 packages/opentelemetry-types/src/trace/tracestate.ts

diff --git a/packages/opentelemetry-types/src/trace/span_context.ts b/packages/opentelemetry-types/src/trace/span_context.ts
index f2a183aa90..98d06dfa46 100644
--- a/packages/opentelemetry-types/src/trace/span_context.ts
+++ b/packages/opentelemetry-types/src/trace/span_context.ts
@@ -14,6 +14,9 @@
  * limitations under the License.
  */
 
+import { TraceState } from './tracestate';
+import { TraceOptions } from './traceoptions';
+
 /**
  * A SpanContext represents the portion of a Span which must be serialized and
  * propagated along side of a distributed context.
@@ -39,7 +42,7 @@ export interface SpanContext {
    * sampled or not.
    * SAMPLED_VALUE = 0x1 and NOT_SAMPLED_VALUE = 0x0;
    */
-  traceOptions?: number;
+  traceOptions?: TraceOptions;
   /**
    * Tracing-system-specific info to propagate.
    *
@@ -56,5 +59,5 @@ export interface SpanContext {
    *     Multiple tracing systems (with different formatting):
    *         tracestate: rojo=00f067aa0ba902b7,congo=t61rcWkgMzE
    */
-  traceState?: string;
+  traceState?: TraceState;
 }
diff --git a/packages/opentelemetry-types/src/trace/traceoptions.ts b/packages/opentelemetry-types/src/trace/traceoptions.ts
new file mode 100644
index 0000000000..f80d46cabb
--- /dev/null
+++ b/packages/opentelemetry-types/src/trace/traceoptions.ts
@@ -0,0 +1,19 @@
+/**
+ * Copyright 2019, OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export class TraceOptions {
+  // TODO
+}
diff --git a/packages/opentelemetry-types/src/trace/tracestate.ts b/packages/opentelemetry-types/src/trace/tracestate.ts
new file mode 100644
index 0000000000..95fbd90969
--- /dev/null
+++ b/packages/opentelemetry-types/src/trace/tracestate.ts
@@ -0,0 +1,19 @@
+/**
+ * Copyright 2019, OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export class TraceState {
+  // TODO
+}

From 53b8093f149276b1adc54ce37bd71e377085a5e7 Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Mon, 17 Jun 2019 22:42:45 -0700
Subject: [PATCH 09/12] Add Link and Attributes interfaces

---
 .../src/trace/attributes.ts                   | 20 +++++++++++++
 .../opentelemetry-types/src/trace/link.ts     | 29 +++++++++++++++++++
 2 files changed, 49 insertions(+)
 create mode 100644 packages/opentelemetry-types/src/trace/attributes.ts
 create mode 100644 packages/opentelemetry-types/src/trace/link.ts

diff --git a/packages/opentelemetry-types/src/trace/attributes.ts b/packages/opentelemetry-types/src/trace/attributes.ts
new file mode 100644
index 0000000000..b2758be2ba
--- /dev/null
+++ b/packages/opentelemetry-types/src/trace/attributes.ts
@@ -0,0 +1,20 @@
+/**
+ * Copyright 2019, OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+ /** Defines a attributes interface. */
+export interface Attributes {
+  [attributeKey: string]: unknown;
+}
diff --git a/packages/opentelemetry-types/src/trace/link.ts b/packages/opentelemetry-types/src/trace/link.ts
new file mode 100644
index 0000000000..0bc4763d8a
--- /dev/null
+++ b/packages/opentelemetry-types/src/trace/link.ts
@@ -0,0 +1,29 @@
+/**
+ * Copyright 2019, OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { Attributes } from './attributes';
+import { SpanContext } from './span_context';
+
+/**
+ * A pointer from the current span to another span in the same trace or in a
+ * different trace.
+ */
+export interface Link {
+  /** The SpanContext of a linked span. */
+  spanContext: SpanContext;
+  /** A set of attributes on the link. */
+  attributes: Attributes;
+}

From 595465cc1d61e5cf0033c9aee0fbb8dc767b4a0a Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Mon, 17 Jun 2019 22:45:49 -0700
Subject: [PATCH 10/12] update index.ts

---
 packages/opentelemetry-types/src/index.ts | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/packages/opentelemetry-types/src/index.ts b/packages/opentelemetry-types/src/index.ts
index 99e37437e9..d1274a20a3 100644
--- a/packages/opentelemetry-types/src/index.ts
+++ b/packages/opentelemetry-types/src/index.ts
@@ -18,3 +18,7 @@ export * from './trace/span';
 export * from './trace/span_context';
 export * from './trace/span_kind';
 export * from './trace/status';
+export * from './trace/link';
+export * from './trace/attributes';
+export * from './trace/traceoptions';
+export * from './trace/tracestate';

From f1d2b7e6f9b023cae44710157e99ec9f2d803f6b Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Tue, 18 Jun 2019 13:21:59 -0700
Subject: [PATCH 11/12] Change Link:attributes as optional property

---
 packages/opentelemetry-types/src/trace/link.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/opentelemetry-types/src/trace/link.ts b/packages/opentelemetry-types/src/trace/link.ts
index 0bc4763d8a..aafbef2bbd 100644
--- a/packages/opentelemetry-types/src/trace/link.ts
+++ b/packages/opentelemetry-types/src/trace/link.ts
@@ -25,5 +25,5 @@ export interface Link {
   /** The SpanContext of a linked span. */
   spanContext: SpanContext;
   /** A set of attributes on the link. */
-  attributes: Attributes;
+  attributes?: Attributes;
 }

From 5c92e516b752424ab48cce739b24b814553eb021 Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Tue, 18 Jun 2019 20:01:40 -0700
Subject: [PATCH 12/12] Fix review comments

---
 packages/opentelemetry-types/src/index.ts                   | 4 ++--
 packages/opentelemetry-types/src/trace/attributes.ts        | 2 +-
 packages/opentelemetry-types/src/trace/span.ts              | 6 +++++-
 packages/opentelemetry-types/src/trace/span_context.ts      | 4 ++--
 .../src/trace/{tracestate.ts => trace_options.ts}           | 2 +-
 .../src/trace/{traceoptions.ts => trace_state.ts}           | 2 +-
 6 files changed, 12 insertions(+), 8 deletions(-)
 rename packages/opentelemetry-types/src/trace/{tracestate.ts => trace_options.ts} (95%)
 rename packages/opentelemetry-types/src/trace/{traceoptions.ts => trace_state.ts} (95%)

diff --git a/packages/opentelemetry-types/src/index.ts b/packages/opentelemetry-types/src/index.ts
index d1274a20a3..9f68cbb66f 100644
--- a/packages/opentelemetry-types/src/index.ts
+++ b/packages/opentelemetry-types/src/index.ts
@@ -20,5 +20,5 @@ export * from './trace/span_kind';
 export * from './trace/status';
 export * from './trace/link';
 export * from './trace/attributes';
-export * from './trace/traceoptions';
-export * from './trace/tracestate';
+export * from './trace/trace_options';
+export * from './trace/trace_state';
diff --git a/packages/opentelemetry-types/src/trace/attributes.ts b/packages/opentelemetry-types/src/trace/attributes.ts
index b2758be2ba..a9fecfac5f 100644
--- a/packages/opentelemetry-types/src/trace/attributes.ts
+++ b/packages/opentelemetry-types/src/trace/attributes.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
- /** Defines a attributes interface. */
+/** Defines a attributes interface. */
 export interface Attributes {
   [attributeKey: string]: unknown;
 }
diff --git a/packages/opentelemetry-types/src/trace/span.ts b/packages/opentelemetry-types/src/trace/span.ts
index 9f2188266c..d5831a1c08 100644
--- a/packages/opentelemetry-types/src/trace/span.ts
+++ b/packages/opentelemetry-types/src/trace/span.ts
@@ -63,7 +63,10 @@ export interface Span {
    * @param [attributes] the attributes that will be added; these are
    *     associated with this link.
    */
-  addLink(spanContext: SpanContext, attributes?: { [key: string]: unknown }): this;
+  addLink(
+    spanContext: SpanContext,
+    attributes?: { [key: string]: unknown }
+  ): this;
 
   /**
    * Sets a status to the span. If used, this will override the default Span
@@ -93,6 +96,7 @@ export interface Span {
    *
    * @param [endTime] the timestamp to set as Span's end time. If not provided,
    *     use the current time as the span's end time.
+   *     TODO (Add timestamp format): https://github.com/open-telemetry/opentelemetry-js/issues/19
    */
   end(endTime?: number): void;
 
diff --git a/packages/opentelemetry-types/src/trace/span_context.ts b/packages/opentelemetry-types/src/trace/span_context.ts
index 98d06dfa46..142db46c6c 100644
--- a/packages/opentelemetry-types/src/trace/span_context.ts
+++ b/packages/opentelemetry-types/src/trace/span_context.ts
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-import { TraceState } from './tracestate';
-import { TraceOptions } from './traceoptions';
+import { TraceState } from './trace_state';
+import { TraceOptions } from './trace_options';
 
 /**
  * A SpanContext represents the portion of a Span which must be serialized and
diff --git a/packages/opentelemetry-types/src/trace/tracestate.ts b/packages/opentelemetry-types/src/trace/trace_options.ts
similarity index 95%
rename from packages/opentelemetry-types/src/trace/tracestate.ts
rename to packages/opentelemetry-types/src/trace/trace_options.ts
index 95fbd90969..dfefc751ba 100644
--- a/packages/opentelemetry-types/src/trace/tracestate.ts
+++ b/packages/opentelemetry-types/src/trace/trace_options.ts
@@ -14,6 +14,6 @@
  * limitations under the License.
  */
 
-export class TraceState {
+export interface TraceOptions {
   // TODO
 }
diff --git a/packages/opentelemetry-types/src/trace/traceoptions.ts b/packages/opentelemetry-types/src/trace/trace_state.ts
similarity index 95%
rename from packages/opentelemetry-types/src/trace/traceoptions.ts
rename to packages/opentelemetry-types/src/trace/trace_state.ts
index f80d46cabb..03c52af68b 100644
--- a/packages/opentelemetry-types/src/trace/traceoptions.ts
+++ b/packages/opentelemetry-types/src/trace/trace_state.ts
@@ -14,6 +14,6 @@
  * limitations under the License.
  */
 
-export class TraceOptions {
+export interface TraceState {
   // TODO
 }