feat(telemetry): initial implementation — OpenTelemetry traces, metrics, logs (v1.0.0)

Introduces code.nochebuena.dev/einherjar/telemetry — the observability bootstrap
starter for the Einherjar framework. Absorbs the telemetry package from micro-lib,
migrating from OpenCensus to OpenTelemetry SDK v1.42.

Bootstrap functions (not lifecycle.Component — telemetry must be initialized before
the launcher starts, and its shutdown must run after all components stop):
- New(ctx, cfg) (func(context.Context) error, error) — production mode; exports
  traces, metrics, and logs via OTLP over gRPC to the configured endpoint;
  returns a shutdown function to be deferred in main()
- NewConsole(ctx, logger, cfg) (func(context.Context) error, error) — development
  mode; writes structured telemetry to the provided logging.Logger; no network
  dependency; suitable for local development and CI

Config (EINHERJAR_OTEL_* env vars):
  ServiceName(required), ServiceVersion(unknown), Environment(development),
  OTLPEndpoint(required for New), OTLPInsecure(false)

ConsoleConfig (EINHERJAR_OTEL_* env vars):
  ServiceName(required), ServiceVersion(unknown), Environment(development)

- identifiable.go: package-level Module variable (observability.Identifiable) for version
  identification — telemetry bootstraps before the launcher; not registered as a lifecycle component
This commit is contained in:
2026-05-29 16:09:54 +00:00
commit b583af1973
16 changed files with 2177 additions and 0 deletions

381
compliance_test.go Normal file
View File

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package telemetry
import (
"context"
"go/ast"
"go/parser"
"go/token"
"net"
"os"
"strings"
"sync"
"testing"
"time"
"go.opentelemetry.io/otel"
sdkmetric "go.opentelemetry.io/otel/sdk/metric"
sdktrace "go.opentelemetry.io/otel/sdk/trace"
"code.nochebuena.dev/einherjar/contracts/logging"
)
// ---------------------------------------------------------------------------
// CT-6: ≤1 exported TypeSpec per file
// ---------------------------------------------------------------------------
func TestAtMostOneExportedTypePerFile(t *testing.T) {
fset := token.NewFileSet()
entries, err := os.ReadDir(".")
if err != nil {
t.Fatalf("ReadDir: %v", err)
}
for _, entry := range entries {
name := entry.Name()
if !strings.HasSuffix(name, ".go") || strings.HasSuffix(name, "_test.go") {
continue
}
f, err := parser.ParseFile(fset, name, nil, 0)
if err != nil {
t.Fatalf("parse %s: %v", name, err)
}
count := 0
for _, decl := range f.Decls {
gd, ok := decl.(*ast.GenDecl)
if !ok {
continue
}
for _, spec := range gd.Specs {
ts, ok := spec.(*ast.TypeSpec)
if !ok {
continue
}
if ts.Name.IsExported() {
count++
}
}
}
if count > 1 {
t.Errorf("%s: has %d exported TypeSpecs, want ≤1", name, count)
}
}
}
// ---------------------------------------------------------------------------
// DefaultConfig / DefaultConsoleConfig
// ---------------------------------------------------------------------------
func TestDefaultConfig_OptionalFields(t *testing.T) {
cfg := DefaultConfig()
if cfg.ServiceVersion != "unknown" {
t.Errorf("ServiceVersion: got %q, want %q", cfg.ServiceVersion, "unknown")
}
if cfg.Environment != "development" {
t.Errorf("Environment: got %q, want %q", cfg.Environment, "development")
}
if cfg.OTLPInsecure {
t.Error("OTLPInsecure: want false by default")
}
}
func TestDefaultConsoleConfig_OptionalFields(t *testing.T) {
cfg := DefaultConsoleConfig()
if cfg.ServiceVersion != "unknown" {
t.Errorf("ServiceVersion: got %q, want %q", cfg.ServiceVersion, "unknown")
}
if cfg.Environment != "development" {
t.Errorf("Environment: got %q, want %q", cfg.Environment, "development")
}
}
// ---------------------------------------------------------------------------
// newResource
// ---------------------------------------------------------------------------
func TestNewResource_Fields(t *testing.T) {
cfg := Config{
ServiceName: "my-service",
ServiceVersion: "2.0.0",
Environment: "staging",
}
res := newResource(cfg)
check := func(key, want string) {
t.Helper()
for _, kv := range res.Attributes() {
if string(kv.Key) == key {
if got := kv.Value.AsString(); got != want {
t.Errorf("resource[%s]: want %q, got %q", key, want, got)
}
return
}
}
t.Errorf("resource attribute %q not found", key)
}
check("service.name", "my-service")
check("service.version", "2.0.0")
check("deployment.environment", "staging")
}
func TestNewResource_MergesWithDefault(t *testing.T) {
res := newResource(Config{ServiceName: "svc"})
if res == nil {
t.Fatal("newResource returned nil")
}
if len(res.Attributes()) == 0 {
t.Error("resource has no attributes")
}
}
// ---------------------------------------------------------------------------
// New — OTLP bootstrap
// ---------------------------------------------------------------------------
// fakeCollector starts a TCP listener that accepts connections but speaks no protocol.
func fakeCollector(t *testing.T) string {
t.Helper()
ln, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
t.Fatalf("fakeCollector: %v", err)
}
t.Cleanup(func() { ln.Close() })
go func() {
for {
conn, err := ln.Accept()
if err != nil {
return
}
conn.Close()
}
}()
return ln.Addr().String()
}
func cfgWith(endpoint string) Config {
return Config{
ServiceName: "test-service",
ServiceVersion: "0.0.1",
Environment: "test",
OTLPEndpoint: endpoint,
OTLPInsecure: true,
}
}
func TestNew_ShutdownCallable(t *testing.T) {
endpoint := fakeCollector(t)
ctx := context.Background()
shutdown, err := New(ctx, cfgWith(endpoint))
if err != nil {
t.Fatalf("New: %v", err)
}
if shutdown == nil {
t.Fatal("shutdown func is nil")
}
shutCtx, cancel := context.WithTimeout(ctx, 200*time.Millisecond)
defer cancel()
_ = shutdown(shutCtx)
}
func TestNew_SetsGlobalTracerProvider(t *testing.T) {
endpoint := fakeCollector(t)
ctx := context.Background()
shutdown, err := New(ctx, cfgWith(endpoint))
if err != nil {
t.Fatalf("New: %v", err)
}
t.Cleanup(func() {
shutCtx, cancel := context.WithTimeout(ctx, 200*time.Millisecond)
defer cancel()
_ = shutdown(shutCtx)
})
if _, ok := otel.GetTracerProvider().(*sdktrace.TracerProvider); !ok {
t.Errorf("expected *sdktrace.TracerProvider, got %T", otel.GetTracerProvider())
}
}
func TestNew_SetsGlobalMeterProvider(t *testing.T) {
endpoint := fakeCollector(t)
ctx := context.Background()
shutdown, err := New(ctx, cfgWith(endpoint))
if err != nil {
t.Fatalf("New: %v", err)
}
t.Cleanup(func() {
shutCtx, cancel := context.WithTimeout(ctx, 200*time.Millisecond)
defer cancel()
_ = shutdown(shutCtx)
})
if _, ok := otel.GetMeterProvider().(*sdkmetric.MeterProvider); !ok {
t.Errorf("expected *sdkmetric.MeterProvider, got %T", otel.GetMeterProvider())
}
}
// ---------------------------------------------------------------------------
// NewConsole — logger-backed exporters
// ---------------------------------------------------------------------------
// stubLogger captures log calls for test assertions. Implements logging.Logger.
type stubLogger struct {
mu sync.Mutex
logs []stubLog
}
type stubLog struct {
level string
msg string
}
func (s *stubLogger) Info(msg string, _ ...any) {
s.mu.Lock()
defer s.mu.Unlock()
s.logs = append(s.logs, stubLog{"info", msg})
}
func (s *stubLogger) Warn(msg string, _ ...any) {
s.mu.Lock()
defer s.mu.Unlock()
s.logs = append(s.logs, stubLog{"warn", msg})
}
func (s *stubLogger) Error(msg string, _ error, _ ...any) {
s.mu.Lock()
defer s.mu.Unlock()
s.logs = append(s.logs, stubLog{"error", msg})
}
func (s *stubLogger) Debug(msg string, _ ...any) {
s.mu.Lock()
defer s.mu.Unlock()
s.logs = append(s.logs, stubLog{"debug", msg})
}
func (s *stubLogger) With(_ ...any) logging.Logger { return s }
func (s *stubLogger) WithContext(_ context.Context) logging.Logger { return s }
func (s *stubLogger) find(msg string) bool {
s.mu.Lock()
defer s.mu.Unlock()
for _, l := range s.logs {
if l.msg == msg {
return true
}
}
return false
}
func consoleCfg() ConsoleConfig {
return ConsoleConfig{
ServiceName: "test-svc",
ServiceVersion: "0.0.1",
Environment: "test",
}
}
func TestNewConsole_ShutdownCallable(t *testing.T) {
logger := &stubLogger{}
ctx := context.Background()
shutdown, err := NewConsole(ctx, logger, consoleCfg())
if err != nil {
t.Fatalf("NewConsole: %v", err)
}
shutCtx, cancel := context.WithTimeout(ctx, 200*time.Millisecond)
defer cancel()
if err := shutdown(shutCtx); err != nil {
t.Errorf("shutdown: %v", err)
}
}
func TestNewConsole_SetsGlobalTracerProvider(t *testing.T) {
logger := &stubLogger{}
ctx := context.Background()
shutdown, err := NewConsole(ctx, logger, consoleCfg())
if err != nil {
t.Fatalf("NewConsole: %v", err)
}
t.Cleanup(func() {
shutCtx, cancel := context.WithTimeout(ctx, 200*time.Millisecond)
defer cancel()
_ = shutdown(shutCtx)
})
if _, ok := otel.GetTracerProvider().(*sdktrace.TracerProvider); !ok {
t.Errorf("expected *sdktrace.TracerProvider, got %T", otel.GetTracerProvider())
}
}
func TestNewConsole_SetsGlobalMeterProvider(t *testing.T) {
logger := &stubLogger{}
ctx := context.Background()
shutdown, err := NewConsole(ctx, logger, consoleCfg())
if err != nil {
t.Fatalf("NewConsole: %v", err)
}
t.Cleanup(func() {
shutCtx, cancel := context.WithTimeout(ctx, 200*time.Millisecond)
defer cancel()
_ = shutdown(shutCtx)
})
if _, ok := otel.GetMeterProvider().(*sdkmetric.MeterProvider); !ok {
t.Errorf("expected *sdkmetric.MeterProvider, got %T", otel.GetMeterProvider())
}
}
func TestNewConsole_ExportsSpan(t *testing.T) {
logger := &stubLogger{}
ctx := context.Background()
shutdown, err := NewConsole(ctx, logger, consoleCfg())
if err != nil {
t.Fatalf("NewConsole: %v", err)
}
defer func() {
shutCtx, cancel := context.WithTimeout(ctx, 200*time.Millisecond)
defer cancel()
_ = shutdown(shutCtx)
}()
tracer := otel.Tracer("test")
_, span := tracer.Start(ctx, "test-span")
span.End() // WithSyncer exports synchronously on End
if !logger.find("otel: span") {
t.Error("expected logger to receive 'otel: span' after span.End()")
}
}
func TestNewConsole_ExportsMetric(t *testing.T) {
logger := &stubLogger{}
ctx := context.Background()
shutdown, err := NewConsole(ctx, logger, consoleCfg())
if err != nil {
t.Fatalf("NewConsole: %v", err)
}
meter := otel.Meter("test")
counter, err := meter.Int64Counter("test.counter")
if err != nil {
t.Fatalf("Int64Counter: %v", err)
}
counter.Add(ctx, 1)
// Force export by shutting down — PeriodicReader flushes on shutdown.
shutCtx, cancel := context.WithTimeout(ctx, 2*time.Second)
defer cancel()
if err := shutdown(shutCtx); err != nil {
t.Errorf("shutdown: %v", err)
}
if !logger.find("otel: metric") {
t.Error("expected logger to receive 'otel: metric' after shutdown flush")
}
}