Update Zipkin instructions. (#246)

Author: g-easy

opencensus/exporters/trace/zipkin/README.md

@@ -1,36 +1,48 @@
 # Zipkin Export Example
 
-This is a simple example program to demonstrate how to export tracing information
-to Zipkin using OpenCensus.
+This is a simple example program to demonstrate how to export tracing
+information to Zipkin using OpenCensus.
 
-Usage:
-
-Start the zipkin server.
+Start the zipkin server:
 ```shell
-java -jar zipkin.jar --logging.level.zipkin=DEBUG --logging.level.zipkin2=DEBUG
+docker run -p 9411:9411 openzipkin/zipkin
+
+# Or, download zipkin and run:
+# java -jar zipkin.jar --logging.level.zipkin=DEBUG --logging.level.zipkin2=DEBUG
 ```
 
-Build and run the OpenCensus example.
+Run the OpenCensus example:
 ```shell
-bazel build opencensus/...
-./bazel-bin/opencensus/exporters/trace/zipkin/zipkin_exporter_test
+bazel run //opencensus/exporters/trace/zipkin:zipkin_exporter_test
 ```
 
-## Zipkin:
+Go to http://127.0.0.1:9411/ and click the "Find Traces" button to see traces.
 
-A Zipkin server needs to be running to collect the spans. Zipkin can be found [here](https://github.com/openzipkin/zipkin). Instructions on running the server can be found [here](https://github.com/openzipkin/zipkin/tree/master/zipkin-server). The Zipkin server should by default listen on port 9411. If you are running the server locally, the spans should be sent to "http://127.0.0.1:9411/api/v2/spans".
+## Zipkin
+
+A Zipkin server needs to be running to send spans to it.
+Zipkin can be found [here](https://github.com/openzipkin/zipkin).
+Instructions on running the server can be found in their
+[quickstart](https://zipkin.io/pages/quickstart.html).
+The Zipkin server should by default listen on port 9411.
 
 Zipkin's tracing model is not identical to the model used by OpenCensus. Here is
- a list of some of the differences when converting from OpenCensus to Zipkin.
+a list of some of the differences when converting from OpenCensus to Zipkin:
 
-**OpenCensus      ->  Zipkin**
-  * message events  ->  annotations (serialized as <SENT/RECEIVED>/\<Id\>/\<size\>)
-  * attributes        ->  tags (which are a dict of key/value pairs in Zipkin)
-  * links             ->  Not Supported
+OpenCensus | Zipkin
+---------- | ------
+message events | annotations (formatted as: SENT/ID/size)
+attributes | tags (which are key/value pairs in Zipkin)
+links | not supported
 
 ## Viewing Example Trace
 
-The traces will show up on the Zipkin webpage UI. If you are using the default address it will be "http://127.0.0.1:9411/zipkin". Click on find traces. The trace sent from the exporter should appear. Click on it and it should look something like this:
+The traces will show up on the Zipkin webpage UI.
+By default, this is http://127.0.0.1:9411/
+
+Click the "Find Traces" button and the trace sent from the exporter should
+appear.
+Click on it and it should look something like this:
 
 ![Example Trace](https://i.imgur.com/7bNWraI.png)