Discover service names from process env vars

pkg/export/alloy/traces.go

@@ -44,14 +44,14 @@ func (tr *tracesReceiver) provideLoop() (pipe.FinalFunc[[]request.Span], error)
 		if err != nil {
 			slog.Error("error fetching user defined attributes", "error", err)
 		}
-		envResourceAttrs := otel.ResourceAttrsFromEnv()
 
 		for spans := range in {
 			for i := range spans {
 				span := &spans[i]
 				if tr.spanDiscarded(span) {
 					continue
 				}
+				envResourceAttrs := otel.ResourceAttrsFromEnv(&span.ServiceID)
 
 				for _, tc := range tr.cfg.Traces {
 					traces := otel.GenerateTraces(span, tr.hostID, traceAttrs, envResourceAttrs)

pkg/export/otel/common.go

@@ -340,7 +340,7 @@ func headersFromEnv(varName string) map[string]string {
 		headers[k] = v
 	}
 
-	parseOTELEnvVar(varName, addToMap)
+	parseOTELEnvVar(nil, varName, addToMap)
 
 	return headers
 }
@@ -352,8 +352,17 @@ type varHandler func(k string, v string)
 // OTEL_RESOURCE_ATTRIBUTES, i.e. a comma-separated list of
 // key=values. For example: api-key=key,other-config-value=value
 // The values are passed as parameters to the handler function
-func parseOTELEnvVar(varName string, handler varHandler) {
-	envVar, ok := os.LookupEnv(varName)
+func parseOTELEnvVar(svc *svc.ID, varName string, handler varHandler) {
+	var envVar string
+	ok := false
+
+	if svc != nil && svc.EnvVars != nil {
+		envVar, ok = svc.EnvVars[varName]
+	}
+
+	if !ok {
+		envVar, ok = os.LookupEnv(varName)
+	}
 
 	if !ok {
 		return
@@ -379,12 +388,12 @@ func parseOTELEnvVar(varName string, handler varHandler) {
 	}
 }
 
-func ResourceAttrsFromEnv() []attribute.KeyValue {
+func ResourceAttrsFromEnv(svc *svc.ID) []attribute.KeyValue {
 	var otelResourceAttrs []attribute.KeyValue
 	apply := func(k string, v string) {
 		otelResourceAttrs = append(otelResourceAttrs, attribute.String(k, v))
 	}
 
-	parseOTELEnvVar(envResourceAttrs, apply)
+	parseOTELEnvVar(svc, envResourceAttrs, apply)
 	return otelResourceAttrs
 }

pkg/export/otel/common_test.go

@@ -7,6 +7,8 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+
+	"github.com/grafana/beyla/pkg/internal/svc"
 )
 
 func TestOtlpOptions_AsMetricHTTP(t *testing.T) {
@@ -123,7 +125,7 @@ func TestParseOTELEnvVar(t *testing.T) {
 
 			assert.NoError(t, err)
 
-			parseOTELEnvVar(dummyVar, apply)
+			parseOTELEnvVar(nil, dummyVar, apply)
 
 			assert.True(t, reflect.DeepEqual(actual, tc.expected))
 
@@ -134,14 +136,53 @@ func TestParseOTELEnvVar(t *testing.T) {
 	}
 }
 
+func TestParseOTELEnvVarPerService(t *testing.T) {
+	type testCase struct {
+		envVar   string
+		expected map[string]string
+	}
+
+	testCases := []testCase{
+		{envVar: "foo=bar", expected: map[string]string{"foo": "bar"}},
+		{envVar: "foo=bar,", expected: map[string]string{"foo": "bar"}},
+		{envVar: "foo=bar,baz", expected: map[string]string{"foo": "bar"}},
+		{envVar: "foo=bar,baz=baz", expected: map[string]string{"foo": "bar", "baz": "baz"}},
+		{envVar: "foo=bar,baz=baz ", expected: map[string]string{"foo": "bar", "baz": "baz"}},
+		{envVar: "  foo=bar, baz=baz ", expected: map[string]string{"foo": "bar", "baz": "baz"}},
+		{envVar: "  foo = bar , baz =baz ", expected: map[string]string{"foo": "bar", "baz": "baz"}},
+		{envVar: "  foo = bar , baz =baz= ", expected: map[string]string{"foo": "bar", "baz": "baz="}},
+		{envVar: ",a=b , c=d,=", expected: map[string]string{"a": "b", "c": "d"}},
+		{envVar: "=", expected: map[string]string{}},
+		{envVar: "====", expected: map[string]string{}},
+		{envVar: "a====b", expected: map[string]string{"a": "===b"}},
+		{envVar: "", expected: map[string]string{}},
+	}
+
+	const dummyVar = "foo"
+
+	for _, tc := range testCases {
+		t.Run(fmt.Sprint(tc), func(t *testing.T) {
+			actual := map[string]string{}
+
+			apply := func(k string, v string) {
+				actual[k] = v
+			}
+
+			parseOTELEnvVar(&svc.ID{EnvVars: map[string]string{dummyVar: tc.envVar}}, dummyVar, apply)
+
+			assert.True(t, reflect.DeepEqual(actual, tc.expected))
+		})
+	}
+}
+
 func TestParseOTELEnvVar_nil(t *testing.T) {
 	actual := map[string]string{}
 
 	apply := func(k string, v string) {
 		actual[k] = v
 	}
 
-	parseOTELEnvVar("NOT_SET_VAR", apply)
+	parseOTELEnvVar(nil, "NOT_SET_VAR", apply)
 
 	assert.True(t, reflect.DeepEqual(actual, map[string]string{}))
 }

pkg/export/otel/metrics.go

@@ -545,7 +545,7 @@ func (mr *MetricsReporter) setupGraphMeters(m *Metrics, meter instrument.Meter)
 func (mr *MetricsReporter) newMetricSet(service *svc.ID) (*Metrics, error) {
 	mlog := mlog().With("service", service)
 	mlog.Debug("creating new Metrics reporter")
-	resourceAttributes := append(getAppResourceAttrs(mr.hostID, service), ResourceAttrsFromEnv()...)
+	resourceAttributes := append(getAppResourceAttrs(mr.hostID, service), ResourceAttrsFromEnv(service)...)
 	resources := resource.NewWithAttributes(semconv.SchemaURL, resourceAttributes...)
 
 	opts := []metric.Option{

pkg/export/otel/traces.go

@@ -198,14 +198,13 @@ func (tr *tracesOTELReceiver) provideLoop() (pipe.FinalFunc[[]request.Span], err
 			return
 		}
 
-		envResourceAttrs := ResourceAttrsFromEnv()
-
 		for spans := range in {
 			for i := range spans {
 				span := &spans[i]
 				if tr.spanDiscarded(span) {
 					continue
 				}
+				envResourceAttrs := ResourceAttrsFromEnv(&span.ServiceID)
 				traces := GenerateTraces(span, tr.ctxInfo.HostID, traceAttrs, envResourceAttrs)
 				err := exp.ConsumeTraces(tr.ctx, traces)
 				if err != nil {

pkg/export/otel/traces_test.go

@@ -590,7 +590,7 @@ func TestGenerateTracesAttributes(t *testing.T) {
 		defer restoreEnvAfterExecution()()
 		require.NoError(t, os.Setenv(envResourceAttrs, "deployment.environment=productions,source.upstream=beyla"))
 		span := request.Span{Type: request.EventTypeHTTP, Method: "GET", Route: "/test", Status: 200}
-		traces := GenerateTraces(&span, "host-id", map[attr.Name]struct{}{}, ResourceAttrsFromEnv())
+		traces := GenerateTraces(&span, "host-id", map[attr.Name]struct{}{}, ResourceAttrsFromEnv(&span.ServiceID))
 
 		assert.Equal(t, 1, traces.ResourceSpans().Len())
 		rs := traces.ResourceSpans().At(0)

pkg/internal/exec/file.go

@@ -24,6 +24,10 @@ type FileInfo struct {
 	Ns             uint32
 }
 
+const (
+	envServiceName = "OTEL_SERVICE_NAME"
+)
+
 func (fi *FileInfo) ExecutableName() string {
 	parts := strings.Split(fi.CmdExePath, "/")
 	return parts[len(parts)-1]
@@ -59,5 +63,17 @@ func FindExecELF(p *services.ProcessInfo, svcID svc.ID) (*FileInfo, error) {
 	} else {
 		return nil, err
 	}
+
+	envVars, err := EnvVars(p.Pid)
+
+	if err != nil {
+		return nil, err
+	}
+
+	file.Service.EnvVars = envVars
+	if svcName, ok := file.Service.EnvVars[envServiceName]; ok {
+		file.Service.Name = svcName
+	}
+
 	return &file, nil
 }

pkg/internal/exec/procenv.go

@@ -0,0 +1,42 @@
+package exec
+
+import (
+	"strings"
+
+	"github.com/prometheus/procfs"
+)
+
+func envStrsToMap(varsStr []string) map[string]string {
+	vars := make(map[string]string, len(varsStr))
+
+	for _, s := range varsStr {
+		keyVal := strings.SplitN(s, "=", 2)
+		if len(keyVal) < 2 {
+			continue
+		}
+		key := strings.TrimSpace(keyVal[0])
+		val := strings.TrimSpace(keyVal[1])
+
+		if key != "" && val != "" {
+			vars[key] = val
+		}
+	}
+
+	return vars
+}
+
+func EnvVars(pid int32) (map[string]string, error) {
+	proc, err := procfs.NewProc(int(pid))
+
+	if err != nil {
+		return nil, err
+	}
+
+	varsStr, err := proc.Environ()
+
+	if err != nil {
+		return nil, err
+	}
+
+	return envStrsToMap(varsStr), nil
+}

pkg/internal/exec/procenv_test.go

@@ -0,0 +1,24 @@
+package exec
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestEnvStrParsing(t *testing.T) {
+	strs := []string{
+		"ok=\"=  =\"",
+		"nothing",
+		"=wrong",
+		"something=somethingelse",
+		"something_empty=",
+		"something= else",
+		"weird==  =",
+		"resources=a=b,c=d,e=  fg",
+		"",
+	}
+
+	res := envStrsToMap(strs)
+	assert.Equal(t, map[string]string{"something": "else", "ok": "\"=  =\"", "weird": "=  =", "resources": "a=b,c=d,e=  fg"}, res)
+}

pkg/internal/svc/svc.go

@@ -78,6 +78,8 @@ type ID struct {
 	// by other metadata if available (e.g., Pod Name, Node Name, etc...)
 	HostName string
 
+	EnvVars map[string]string
+
 	flags idFlags
 }
 

test/integration/docker-compose-ruby.yml

@@ -5,6 +5,9 @@ services:
     image: ghcr.io/grafana/beyla-test/greeting-rails${TESTSERVER_IMAGE_SUFFIX}/0.0.1
     ports:
       - "${TEST_SERVICE_PORTS}"
+    environment:
+      OTEL_SERVICE_NAME: "my-ruby-app"
+      OTEL_RESOURCE_ATTRIBUTES: "data-center=ca,deployment-zone=to"
     depends_on:
       otelcol:
         condition: service_started

test/integration/red_test_ruby.go

@@ -48,6 +48,18 @@ func testREDMetricsForRubyHTTPLibrary(t *testing.T, url string, comm string) {
 		}
 	})
 
+	// check that the resource attributes we passed made it for the service
+	test.Eventually(t, testTimeout, func(t require.TestingT) {
+		var err error
+		results, err = pq.Query(`target_info{` +
+			`data_center="ca",` +
+			`deployment_zone="to"}`)
+		require.NoError(t, err)
+		enoughPromResults(t, results)
+		val := totalPromCount(t, results)
+		assert.LessOrEqual(t, 1, val)
+	})
+
 	// Call 4 times the instrumented service, forcing it to:
 	// - process multiple calls in a row with, one more than we might need
 	// - returning a 200 code
@@ -83,7 +95,7 @@ func testREDMetricsRailsHTTP(t *testing.T) {
 	} {
 		t.Run(testCaseURL, func(t *testing.T) {
 			waitForRubyTestComponents(t, testCaseURL)
-			testREDMetricsForRubyHTTPLibrary(t, testCaseURL, "ruby")
+			testREDMetricsForRubyHTTPLibrary(t, testCaseURL, "my-ruby-app")
 		})
 	}
 }
@@ -94,7 +106,7 @@ func testREDMetricsRailsHTTPS(t *testing.T) {
 	} {
 		t.Run(testCaseURL, func(t *testing.T) {
 			waitForRubyTestComponents(t, testCaseURL)
-			testREDMetricsForRubyHTTPLibrary(t, testCaseURL, "ruby")
+			testREDMetricsForRubyHTTPLibrary(t, testCaseURL, "my-ruby-app")
 		})
 	}
 }