feat: include Go version, GOOS, & GOARCH in user-agent (#207)

## Which problem is this PR solving?

It helps Honeycomb support customers to know what operating systems
and CPU architectures instrumentation is running upon. OpenTelemetry
has added this to the Collector and the spec for Exporters and we have
[prior art for this in
libhoney-rb](honeycombio/libhoney-rb#105).

## Short description of the changes

- Updated the user-agent to include Go version, GOOS, and GOARCH

- Makefile addition with a test target to bring the CI test execution
  mechanism up-to-date with what we're doing in other Go codebases
  to make it easy to run the tests, make it each to read the test output,
  and give CI the data it needs to helps us see test failures more clearly.

- Moved our libhoney version declaration out of the parent libhoney
  package and into version so that other packages (transmission) can
  reference it. That allows the usual user-agent to be pre-computed.

- User-agent assertions updated to use testify because the failure
  output for diffs is so much friendlier.

.circleci/config.yml

@@ -62,8 +62,9 @@ jobs:
       - buildevents/with_job_span:
           steps:
             - checkout
-            - run: go get -v -t -d ./...
-            - run: go test -race -v ./...
+            - run: make test
+            - store_test_results:
+                path: ./unit-tests.xml
             - buildevents/add_context:
                 field_name: go_version
                 field_value: << parameters.goversion >>

.gitignore

@@ -1,6 +1,9 @@
 # Example artifacts
 examples/wiki-manual-tracing/*.txt
 
+# Test report
+unit-tests.xml
+
 # Compiled Object files, Static and Dynamic libs (Shared Objects)
 *.o
 *.a

Makefile

@@ -0,0 +1,11 @@
+.PHONY: test
+#: run the tests!
+test:
+ifeq (, $(shell which gotestsum))
+	@echo " ***"
+	@echo "Running with standard go test because gotestsum was not found on PATH. Consider installing gotestsum for friendlier test output!"
+	@echo " ***"
+	go test -race -v ./...
+else
+	gotestsum --junitfile unit-tests.xml --format testname -- -race ./...
+endif

RELEASING.md

@@ -1,6 +1,6 @@
 # Creating a new release
 
-1. Update the version string in `libhoney.go`.
+1. Update the Version string in `version/version.go`.
 2. Add new release notes to the Changelog.
 3. Open a PR with above changes.
 4. Once the above PR is merged, tag `main` with the new version, e.g. `v0.1.1`. Push the tags. This will kick off a CI workflow, which will publish a draft GitHub release.

libhoney.go

@@ -27,15 +27,13 @@ import (
 
 func init() {
 	rand.Seed(time.Now().UnixNano())
-	transmission.Version = version
 }
 
 const (
 	defaultSampleRate     = 1
 	defaultAPIHost        = "https://api.honeycomb.io/"
 	defaultClassicDataset = "libhoney-go dataset"
 	defaultDataset        = "unknown_dataset"
-	version               = "1.17.1"
 
 	// DefaultMaxBatchSize how many events to collect in a batch
 	DefaultMaxBatchSize = 50

transmission/transmission.go

@@ -20,11 +20,13 @@ import (
 	"net/http"
 	"net/url"
 	"path"
+	"runtime"
 	"strings"
 	"sync"
 	"time"
 
 	"github.com/facebookgo/muster"
+	"github.com/honeycombio/libhoney-go/version"
 	"github.com/klauspost/compress/zstd"
 	"github.com/vmihailenco/msgpack/v5"
 )
@@ -39,8 +41,23 @@ const (
 	defaultSendTimeout = time.Second * 60
 )
 
-// Version is the build version, set by libhoney
-var Version string
+var (
+	// Libhoney's portion of the User-Agent header, e.g. "libhoney/1.2.3"
+	baseUserAgent = fmt.Sprintf("libhoney-go/%s", version.Version)
+	// Information about the runtime environment for inclusion in User-Agent
+	runtimeInfo = fmt.Sprintf("%s (%s/%s)", strings.Replace(runtime.Version(), "go", "go/", 1), runtime.GOOS, runtime.GOARCH)
+	// The default User-Agent when no additions have been given
+	defaultUserAgent = fmt.Sprintf("%s %s", baseUserAgent, runtimeInfo)
+)
+
+// Return a user-agent value including any additions made in the configuration
+func fmtUserAgent(addition string) string {
+	if addition != "" {
+		return fmt.Sprintf("%s %s %s", baseUserAgent, strings.TrimSpace(addition), runtimeInfo)
+	} else {
+		return defaultUserAgent
+	}
+}
 
 type Honeycomb struct {
 	// How many events to collect into a batch before sending. A
@@ -407,12 +424,6 @@ func (b *batchAgg) fireBatch(events []*Event) {
 	// build the HTTP request
 	url.Path = path.Join(url.Path, "/1/batch", dataset)
 
-	// sigh. dislike
-	userAgent := fmt.Sprintf("libhoney-go/%s", Version)
-	if b.userAgentAddition != "" {
-		userAgent = fmt.Sprintf("%s %s", userAgent, strings.TrimSpace(b.userAgentAddition))
-	}
-
 	// One retry allowed for connection timeouts.
 	var resp *http.Response
 	for try := 0; try < 2; try++ {
@@ -435,7 +446,7 @@ func (b *batchAgg) fireBatch(events []*Event) {
 			req.Header.Set("Content-Encoding", "zstd")
 		}
 
-		req.Header.Set("User-Agent", userAgent)
+		req.Header.Set("User-Agent", fmtUserAgent(b.userAgentAddition))
 		req.Header.Add("X-Honeycomb-Team", writeKey)
 		// send off batch!
 		resp, err = b.httpClient.Do(req)

transmission/transmission_test.go

@@ -22,6 +22,8 @@ import (
 	// convincing testing.
 	"github.com/DataDog/zstd"
 	"github.com/facebookgo/muster"
+	"github.com/honeycombio/libhoney-go/version"
+	"github.com/stretchr/testify/assert"
 	"github.com/vmihailenco/msgpack/v5"
 )
 
@@ -201,7 +203,6 @@ func TestTxSendSingle(t *testing.T) {
 			metrics:               &nullMetrics{},
 			enableMsgpackEncoding: doMsgpack,
 		}
-		Version = "1.2.3"
 		reset := func(b *batchAgg, frt *FakeRoundTripper, statusCode int, body string, err error) {
 			if body == "" {
 				frt.resp = nil
@@ -229,8 +230,8 @@ func TestTxSendSingle(t *testing.T) {
 		b.Fire(&testNotifier{})
 		expectedURL := fmt.Sprintf("%s/1/batch/%s", e.APIHost, e.Dataset)
 		testEquals(t, frt.req.URL.String(), expectedURL)
-		versionedUserAgent := fmt.Sprintf("libhoney-go/%s", Version)
-		testEquals(t, frt.req.Header.Get("User-Agent"), versionedUserAgent)
+		versionedUserAgent := fmt.Sprintf("libhoney-go/%s %s", version.Version, runtimeInfo)
+		assert.Equal(t, versionedUserAgent, frt.req.Header.Get("User-Agent"))
 		testEquals(t, frt.req.Header.Get("X-Honeycomb-Team"), e.APIKey)
 		buf := &bytes.Buffer{}
 		g := zstd.NewWriter(buf)
@@ -269,11 +270,11 @@ func TestTxSendSingle(t *testing.T) {
 		// test UserAgentAddition
 		b.userAgentAddition = "  fancyApp/3 "
 		expectedUserAgentAddition := "fancyApp/3"
-		longUserAgent := fmt.Sprintf("%s %s", versionedUserAgent, expectedUserAgentAddition)
+		longUserAgent := fmt.Sprintf("libhoney-go/%s %s %s", version.Version, expectedUserAgentAddition, runtimeInfo)
 		reset(b, frt, 200, `[{"status":202}]`, nil)
 		b.Add(e)
 		b.Fire(&testNotifier{})
-		testEquals(t, frt.req.Header.Get("User-Agent"), longUserAgent)
+		assert.Equal(t, longUserAgent, frt.req.Header.Get("User-Agent"))
 		rsp = testGetResponse(t, b.responses)
 		testEquals(t, rsp.StatusCode, 202)
 		testOK(t, rsp.Err)

version/version.go

@@ -0,0 +1,5 @@
+package version
+
+const (
+	Version string = "1.17.1"
+)