substrate/internal/serverboot/serverboot_test.go

// Copyright 2026 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package serverboot

import (
	"bytes"
	"context"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"

	"github.com/prometheus/client_golang/prometheus/promhttp"
	"go.opentelemetry.io/otel/sdk/resource"
	semconv "go.opentelemetry.io/otel/semconv/v1.21.0"
)

func resourceAttrs(res *resource.Resource) map[string]string {
	m := make(map[string]string)
	for _, kv := range res.Attributes() {
		m[string(kv.Key)] = kv.Value.Emit()
	}
	return m
}

func TestNewResourceDefaults(t *testing.T) {
	res, err := newResource(context.Background(), "ateapi")
	if err != nil {
		t.Fatalf("newResource: %v", err)
	}
	attrs := resourceAttrs(res)
	if got := attrs[string(semconv.ServiceNameKey)]; got != "ateapi" {
		t.Errorf("service.name = %q, want ateapi", got)
	}
	if attrs[string(semconv.ServiceInstanceIDKey)] == "" {
		t.Error("service.instance.id must be set")
	}
}

func TestNewResourceEnvWins(t *testing.T) {
	t.Setenv("OTEL_SERVICE_NAME", "from-env")
	t.Setenv("OTEL_RESOURCE_ATTRIBUTES", "service.instance.id=fixed-id")
	res, err := newResource(context.Background(), "ateapi")
	if err != nil {
		t.Fatalf("newResource: %v", err)
	}
	attrs := resourceAttrs(res)
	if got := attrs[string(semconv.ServiceNameKey)]; got != "from-env" {
		t.Errorf("service.name = %q, want from-env (OTEL_SERVICE_NAME must win)", got)
	}
	if got := attrs[string(semconv.ServiceInstanceIDKey)]; got != "fixed-id" {
		t.Errorf("service.instance.id = %q, want fixed-id (OTEL_RESOURCE_ATTRIBUTES must win)", got)
	}
}

func TestReadyzDrainsWhileHealthzStaysUp(t *testing.T) {
	readiness := &Readiness{}
	mux := metricsMux(MetricsServerOptions{
		Readiness:     readiness,
		EnableHealthz: true,
	})

	if got := getCode(t, mux, "/readyz"); got != http.StatusOK {
		t.Errorf("/readyz before drain = %d, want %d", got, http.StatusOK)
	}
	if got := getCode(t, mux, "/healthz"); got != http.StatusOK {
		t.Errorf("/healthz before drain = %d, want %d", got, http.StatusOK)
	}

	readiness.MarkNotReady()

	if got := getCode(t, mux, "/readyz"); got != http.StatusServiceUnavailable {
		t.Errorf("/readyz during drain = %d, want %d", got, http.StatusServiceUnavailable)
	}
	if got := getCode(t, mux, "/healthz"); got != http.StatusOK {
		t.Errorf("/healthz during drain = %d, want %d (liveness must not fail while draining)", got, http.StatusOK)
	}
}

func TestReadyzStaticWithZeroValueReadiness(t *testing.T) {
	mux := metricsMux(MetricsServerOptions{Readiness: &Readiness{}})
	if got := getCode(t, mux, "/readyz"); got != http.StatusOK {
		t.Errorf("/readyz with zero-value Readiness = %d, want %d", got, http.StatusOK)
	}
}

func TestReadyzAbsentWithoutReadiness(t *testing.T) {
	mux := metricsMux(MetricsServerOptions{})
	if got := getCode(t, mux, "/readyz"); got != http.StatusNotFound {
		t.Errorf("/readyz with nil Readiness = %d, want %d", got, http.StatusNotFound)
	}
}

func TestHealthzAbsentUnlessEnabled(t *testing.T) {
	mux := metricsMux(MetricsServerOptions{Readiness: &Readiness{}})
	if got := getCode(t, mux, "/healthz"); got != http.StatusNotFound {
		t.Errorf("/healthz without EnableHealthz = %d, want %d", got, http.StatusNotFound)
	}
}

func TestInitMetricsPushOnlyHasNoPrometheusSurface(t *testing.T) {
	mp, err := InitMetricsPushOnly(context.Background(), "test-pushonly")
	if err != nil {
		t.Fatalf("InitMetricsPushOnly: %v", err)
	}
	// Bound shutdown: the periodic reader would otherwise block flushing to the
	// unreachable default OTLP endpoint until the export timeout.
	t.Cleanup(func() {
		ctx, cancel := context.WithTimeout(context.Background(), time.Second)
		defer cancel()
		_ = mp.Shutdown(ctx)
	})

	ctr, err := mp.Meter("test").Int64Counter("ate.test.pushonly.count")
	if err != nil {
		t.Fatalf("create counter: %v", err)
	}
	ctr.Add(context.Background(), 1)

	// A push-only provider registers no Prometheus reader, so what it records must
	// not surface on the default registry StartMetricsServer's /metrics serves.
	rec := httptest.NewRecorder()
	promhttp.Handler().ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/metrics", nil))
	if strings.Contains(rec.Body.String(), "ate_test_pushonly") {
		t.Error("push-only MeterProvider must not expose a Prometheus pull surface")
	}
}

func TestInitMetricsPushOnlyRequiresServiceName(t *testing.T) {
	if _, err := InitMetricsPushOnly(context.Background(), ""); err == nil {
		t.Error("InitMetricsPushOnly(\"\") must return an error")
	}
}

func TestInitMetricsRequiresServiceName(t *testing.T) {
	if _, err := InitMetrics(context.Background(), ""); err == nil {
		t.Error("InitMetrics(\"\") must return an error")
	}
}

func getCode(t *testing.T, mux *http.ServeMux, path string) int {
	t.Helper()
	rec := httptest.NewRecorder()
	mux.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, path, nil))
	return rec.Code
}

func TestSetLogLevel(t *testing.T) {
	t.Cleanup(func() { logLevel.Set(slog.LevelInfo) })

	// The untouched default must be exactly info: every existing deployment
	// relies on this for "no behavior change without the flag".
	if got := logLevel.Level(); got != slog.LevelInfo {
		t.Fatalf("default log level = %v, want %v", got, slog.LevelInfo)
	}

	var buf bytes.Buffer
	InitLoggerWithWriter(&buf)
	t.Cleanup(InitLogger)

	slog.Info("visible at default level")
	if !strings.Contains(buf.String(), "visible at default level") {
		t.Errorf("info line not emitted at default level: %s", buf.String())
	}
	buf.Reset()
	slog.Debug("hidden at default level")
	if buf.Len() != 0 {
		t.Errorf("debug line emitted at default level: %s", buf.String())
	}

	if err := SetLogLevel("debug"); err != nil {
		t.Fatalf("SetLogLevel(debug): %v", err)
	}
	slog.Debug("visible at debug")
	if !strings.Contains(buf.String(), "visible at debug") {
		t.Errorf("debug line not emitted after SetLogLevel(debug): %s", buf.String())
	}

	// Case-insensitive, and dynamic: raising the level silences info.
	if err := SetLogLevel("WARN"); err != nil {
		t.Fatalf("SetLogLevel(WARN): %v", err)
	}
	buf.Reset()
	slog.Info("hidden at warn")
	if buf.Len() != 0 {
		t.Errorf("info line emitted at warn level: %s", buf.String())
	}

	if err := SetLogLevel("verbose"); err == nil {
		t.Error("SetLogLevel accepted an invalid level")
	}

	// Empty means unset: no error, level unchanged.
	if err := SetLogLevel(""); err != nil {
		t.Errorf("SetLogLevel(\"\") = %v, want nil", err)
	}
	if got := logLevel.Level(); got != slog.LevelWarn {
		t.Errorf("SetLogLevel(\"\") changed the level to %v", got)
	}
}