From bb6db538663b5ef1f9ec57d4dbfeae9a0804ae97 Mon Sep 17 00:00:00 2001
From: Dave Raffensperger <daveraff@google.com>
Date: Mon, 9 Sep 2019 20:05:50 -0400
Subject: [PATCH] Update changelog and scripts for B3 propagation (#176)

---
 .circleci/config.yml                           |  1 +
 CHANGELOG.md                                   |  6 +++++-
 README.md                                      |  4 ++++
 RELEASING.md                                   |  3 +++
 .../opencensus-web-propagation-b3/README.md    | 18 ++++++++++++++++++
 5 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index 3778d278..1cfc0a34 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -56,6 +56,7 @@ jobs:
       - run: .circleci/publish.sh exporter-ocagent $WOMBAT_TOKEN_EXPORTER_OCAGENT
       - run: .circleci/publish.sh instrumentation-perf $WOMBAT_TOKEN_INSTRUMENTATION_PERF
       - run: .circleci/publish.sh propagation-tracecontext "$WOMBAT_TOKEN_PROPAGATION_TRACECONTEXT"
+      - run: .circleci/publish.sh propagation-b3 "$WOMBAT_TOKEN_PROPAGATION_B3"
       - run: .circleci/publish.sh scripts "$WOMBAT_TOKEN_SCRIPTS"      
       - run: .circleci/publish.sh types "$WOMBAT_TOKEN_TYPES"
       - run: .circleci/publish.sh instrumentation-zone $WOMBAT_TOKEN_INSTRUMENTATION_ZONE
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2d70d6d9..b6c881a7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,11 @@
 
 All notable changes to this project will be documented in this file.
 
-## unreleased
+## Unreleased
+
+- Support for B3 propagation with new `@opencensus/web-propagation-b3` package
+  and the ability to pass it in via `startTracing({ propagation: Propagation })`.
+  Thanks @edvinasbartkus!
 
 ## 0.0.6 - 2019-08-26
 
diff --git a/README.md b/README.md
index bf775684..11c47957 100644
--- a/README.md
+++ b/README.md
@@ -307,6 +307,9 @@ If you already have a JS build pipeline using e.g. webpack or similar, you can d
   // As the tracing has started, the coming user interactions ares also traced.
   startTracing();
   ```
+The default propagation uses the [W3C Trace Context](https://www.w3.org/TR/trace-context/) format. You can also use
+[Zipkin's B3 Propagation](https://github.com/openzipkin/b3-propagation). See the 
+[@opencensus/web-propagation-b3 README][package-web-propagation-b3] for details.
 
 ### 3. Optional: Send a trace parent and sampling decision from your server
 
@@ -448,6 +451,7 @@ Apache 2.0 - See [LICENSE][license-url] for more information.
 [package-web-initial-load]: https://github.com/census-instrumentation/opencensus-web/tree/master/packages/opencensus-web-initial-load
 [package-web-instrumentation-perf]: https://github.com/census-instrumentation/opencensus-web/tree/master/packages/opencensus-web-instrumentation-perf
 [package-web-propagation-tracecontext]: https://github.com/census-instrumentation/opencensus-web/tree/master/packages/opencensus-web-propagation-tracecontext
+[package-web-propagation-b3]: https://github.com/census-instrumentation/opencensus-web/tree/master/packages/opencensus-web-propagation-b3
 [package-web-types]: https://github.com/census-instrumentation/opencensus-web/tree/master/packages/opencensus-web-types
 [package-web-instrumentation-zone]: https://github.com/census-instrumentation/opencensus-web/tree/master/packages/opencensus-web-instrumentation-zone
 [package-web-instrumentation-zone-peer-dep]: https://github.com/census-instrumentation/opencensus-web/tree/master/packages/opencensus-web-instrumentation-zone-peer-dep
diff --git a/RELEASING.md b/RELEASING.md
index 1f7a550b..9e87c1e8 100644
--- a/RELEASING.md
+++ b/RELEASING.md
@@ -62,6 +62,9 @@ publishes the packages to NPM. See the
 
 ## Update CHANGELOG and release versions in examples
 * After releasing, you need to update all examples to the latest version.
+* You will also need to update the `src` tags of `<script>` links in
+  `README.md` with not only their latest version but also their updated SHA
+  hashes. Use [srihash.org/](https://www.srihash.org/) to easily generate these.
 * In addition, update the CHANGELOG.md and start new Unreleased label.
 * Create a new commit with the exact title: `Post Release: update CHANGELOG, Examples and ReadMe`.
 * Go through PR review and merge it to GitHub master branch.
diff --git a/packages/opencensus-web-propagation-b3/README.md b/packages/opencensus-web-propagation-b3/README.md
index bde95f5d..07b8c888 100644
--- a/packages/opencensus-web-propagation-b3/README.md
+++ b/packages/opencensus-web-propagation-b3/README.md
@@ -20,6 +20,24 @@ See the [OpenCensus Web readme][oc-web-readme-url] for details.
 This is used to propagate trace contextspans for XHRs in the user interactions, 
 serializing a `B3` headers to send along to XHR calls.
 
+It gets passed as an option to the `startTracing` function as follows:
+
+```js
+// Use @opencensus/web-instrumentation-zone-peer-dep instead in case your app
+// already uses `Zone.js`.
+import { startTracing } from '@opencensus/web-instrumentation-zone';
+import { B3Format } from '@opencensus/web-propagation-b3';
+
+window.ocAgent = 'https://example.com/my-opencensus-agent-endpoint';
+window.ocSampleRate = 1.0; // Sample at 100% for test only. Default is 1/10000.
+// Send the trace header to all hosts.
+window.ocTraceHeaderHostRegex = /.*/;
+
+// This methods starts the tracing and exports the initial page load trace.
+// As the tracing has started, the coming user interactions ares also traced.
+startTracing({ propagation: new B3Format() });
+```
+
 ## Useful links
 - For more information on OpenCensus, visit: <https://opencensus.io/>
 - For more about OpenCensus Web: <https://github.com/census-instrumentation/opencensus-web>