[hotrod] Add links to traces

CONTRIBUTING.md

@@ -14,7 +14,7 @@ We gratefully welcome improvements to documentation as well as to code.
 ## Getting Started
 
 ### Pre-requisites
-* Install [Go](https://golang.org/doc/install) and setup GOPATH and add $GOPATH/bin in PATH 
+* Install [Go](https://golang.org/doc/install) and setup GOPATH and add $GOPATH/bin in PATH
 
 This library uses Go modules to manage dependencies.
 
@@ -116,18 +116,32 @@ import (
 
 ## Testing guidelines
 
-We strive to maintain as high code coverage as possible. Since `go test` command does not generate
+We strive to maintain as high code coverage as possible. The current repository limit is set at 95%,
+with some exclusions discussed below.
+
+### Combining code coverage
+
+We use [cover.sh](./scripts/cover.sh) script to run tests and combine code coverage from all packages
+(see also [issue # 797](https://github.com/jaegertracing/jaeger/issues/797)).
+
+### Packages with no tests
+
+Since `go test` command does not generate
 code coverage information for packages that have no test files, we have a build step (`make nocover`)
-that breaks the build when such packages are discovered, with an error like this:
+that breaks the build when such packages are discovered, with the following error:
 
 ```
 error: at least one *_test.go file must be in all directories with go files
        so that they are counted for code coverage.
        If no tests are possible for a package (e.g. it only defines types), create empty_test.go
 ```
 
+As the message says, all packages are required to have at least one `*_test.go` file.
+
+### Excluding packages from testing
+
 There are conditions that cannot be tested without external dependencies, such as a function that
-creates a gocql.Session, because it requires an active connection to Cassandra database. It is
+creates a `gocql.Session`, because it requires an active connection to Cassandra database. It is
 recommended to isolate such functions in a separate package with bare minimum of code and add a
 file `.nocover` to exclude the package from coverage calculations. The file should contain
 a comment explaining why it is there, for example:
@@ -145,4 +159,3 @@ Before merging a PR make sure:
 
 Merge the PR by using "Squash and merge" option on Github. Avoid creating merge commits.
 After the merge make sure referenced issues were closed.
-

examples/hotrod/docker-compose.yml

@@ -14,6 +14,8 @@ services:
     command: ["all"]
     environment:
       - JAEGER_AGENT_HOST=jaeger
+      # Note: if your application is using Node.js Jaeger Client, you need port 6832,
+      #       unless issue https://github.com/jaegertracing/jaeger/issues/1596 is resolved.
       - JAEGER_AGENT_PORT=6831
     networks:
       - jaeger-example

examples/hotrod/services/frontend/web_assets/index.html

@@ -85,7 +85,8 @@ <h4><em>Rides On Demand</em></h4>
       var after = Date.now();
       console.log(data);
       var duration = formatDuration(data.ETA);
-      freshCar.html('HotROD <b>' + data.Driver + '</b> arriving in ' + duration + ' [req: ' + requestID + ', latency: ' + (after-before) + 'ms]');
+      var trace = 'http://localhost:16686/search?limit=20&lookback=1h&service=frontend&tags=%7B%22driver%22%3A%22' + data.Driver + '%22%7D';
+      freshCar.html(`HotROD <b>${data.Driver}</b> arriving in ${duration} [req: ${requestID}, latency: ${after-before}ms] [<a href="${trace}" target="_blank">find trace</a>]`);
     },
   });
 });