feat: show line:count in assertion; use global variables for httpmetrics

Author: roman-vanesyan

debug/assert.go

@@ -9,6 +9,8 @@ import "fmt"
 // Assert calls are ignore when "noassert" build tag is provided.
 func Assert(condition bool, m string, args ...any) {
 	if !condition {
-		panic(fmt.Errorf(m, args...))
+
+		c := caller(3) // [caller, closure, Debuglog]
+		panic(fmt.Errorf("%s: %s", c, fmt.Sprintf(m, args...)))
 	}
 }

debug/caller.go

@@ -0,0 +1,25 @@
+package debug
+
+import (
+	"fmt"
+	"path/filepath"
+	"runtime"
+)
+
+//go:noinline
+func caller(skip int) string {
+	var pcs [1]uintptr
+	runtime.Callers(skip, pcs[:])
+	cf := runtime.CallersFrames([]uintptr{pcs[0]})
+	f, _ := cf.Next()
+
+	var caller string
+	if f.File != "" {
+		file, line := f.File, f.Line
+		dir, file := filepath.Split(file)
+
+		return fmt.Sprintf("%s:%d", filepath.Join(filepath.Base(dir), file), line)
+	}
+
+	return caller
+}

debug/debuglog.go

@@ -5,8 +5,6 @@ package debug
 import (
 	"fmt"
 	"os"
-	"path/filepath"
-	"runtime"
 )
 
 // Debuglog creates a print function that prints a message to stdout.
@@ -18,23 +16,8 @@ import (
 func Debuglog(tag string) func(string, ...any) {
 	return func(m string, args ...any) {
 		pid := os.Getpid()
+		c := caller(3) // [caller, closure, Debuglog]
 
-		var pcs [1]uintptr
-		runtime.Callers(2, pcs[:]) // skip [Debuglog, closure]
-		cf := runtime.CallersFrames([]uintptr{pcs[0]})
-		f, _ := cf.Next()
-
-		var caller string
-		if f.File != "" {
-			file, line := f.File, f.Line
-			caller = format(file, line)
-		}
-
-		fmt.Println(fmt.Sprintf("%s %d [%s]: %s", tag, pid, caller, fmt.Sprintf(m, args...)))
+		fmt.Println(fmt.Sprintf("%s %d %s: %s", tag, pid, c, fmt.Sprintf(m, args...)))
 	}
 }
-
-func format(file string, line int) string {
-	dir, file := filepath.Split(file)
-	return fmt.Sprintf("%s:%d", filepath.Join(filepath.Base(dir), file), line)
-}

metrics/httpmetrics/httpmetrics.go

@@ -6,30 +6,31 @@ import (
 	"github.com/felixge/httpsnoop"
 	"go.inout.gg/foundations/http/httpmiddleware"
 	"go.inout.gg/foundations/must"
+	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/metric"
 )
 
-// Middleware returns a middleware that captures metrics for incoming HTTP requests.
-func Middleware(p metric.MeterProvider) httpmiddleware.Middleware {
-	meter := p.Meter("foundations:httpmetrics")
-	requestDurationHisto := must.Must(
-		meter.Int64Histogram(
-			"request_duration_ms",
-			metric.WithDescription("The incoming request duration in milliseconds."),
-			metric.WithUnit("ms"),
-			metric.WithExplicitBucketBoundaries(1, 5, 10, 25, 50, 100, 200, 500, 1_000, 5_000, 10_000, 30_000, 60_000),
-		),
-	)
-	responseBodySizeHisto := must.Must(
-		meter.Int64Histogram(
-			"response_body_size_bytes",
-			metric.WithDescription("The outgoing response body size in bytes."),
-			metric.WithUnit("bytes"),
-			metric.WithExplicitBucketBoundaries(1, 10, 100, 1_000, 10_000, 100_000, 1_000_000, 10_000_000),
-		),
-	)
+var (
+	provider = otel.GetMeterProvider()
+	meter    = provider.Meter("foundations:httpmetrics")
+
+	requestDurationHisto = must.Must(meter.Int64Histogram(
+		"request_duration_ms",
+		metric.WithDescription("The incoming request duration in milliseconds."),
+		metric.WithUnit("ms"),
+		metric.WithExplicitBucketBoundaries(1, 5, 10, 25, 50, 100, 200, 500, 1_000, 5_000, 10_000, 30_000, 60_000),
+	))
+	responseBodySizeHisto = must.Must(meter.Int64Histogram(
+		"response_body_size_bytes",
+		metric.WithDescription("The outgoing response body size in bytes."),
+		metric.WithUnit("bytes"),
+		metric.WithExplicitBucketBoundaries(1, 10, 100, 1_000, 10_000, 100_000, 1_000_000, 10_000_000),
+	))
+)
 
+// Middleware returns a middleware that captures metrics for incoming HTTP requests.
+func Middleware() httpmiddleware.Middleware {
 	return httpmiddleware.MiddlewareFunc(func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			ctx := r.Context()