Pull request 115: add-kv

Squashed commit of the following:

commit a80373e
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Wed Aug 7 17:50:50 2024 +0300

    container: imp docs

commit 2f67a14
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Wed Aug 7 17:35:26 2024 +0300

    container: add KeyValue

container/keyvalue.go

@@ -0,0 +1,12 @@
+package container
+
+// KeyValue is a simple structure for pairs of values where one identifies the
+// other.  It is useful when multiple values need to be processed in a defined
+// order and each value is associated with its own name or ID.
+type KeyValue[K comparable, V any] struct {
+	Key   K
+	Value V
+}
+
+// KeyValues is a slice of [KeyValue]s.
+type KeyValues[K comparable, V any] []KeyValue[K, V]

container/keyvalue_example_test.go

@@ -0,0 +1,44 @@
+package container_test
+
+import (
+	"fmt"
+
+	"github.com/AdguardTeam/golibs/container"
+)
+
+func ExampleKeyValues() {
+	type service struct{}
+
+	var (
+		serviceA = service{}
+		serviceB = service{}
+		serviceC = service{}
+	)
+
+	type svcName string
+
+	validate := func(_ service) (err error) {
+		return nil
+	}
+
+	// These should be validated in this order.
+	services := container.KeyValues[svcName, service]{{
+		Key:   "svc_a",
+		Value: serviceA,
+	}, {
+		Key:   "svc_b",
+		Value: serviceB,
+	}, {
+		Key:   "svc_c",
+		Value: serviceC,
+	}}
+
+	for _, kv := range services {
+		fmt.Printf("validating service %q: %v\n", kv.Key, validate(kv.Value))
+	}
+
+	// Output:
+	// validating service "svc_a": <nil>
+	// validating service "svc_b": <nil>
+	// validating service "svc_c": <nil>
+}

netutil/httputil/logmw.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/AdguardTeam/golibs/logutil/slogutil"
+	"github.com/AdguardTeam/golibs/timeutil"
 )
 
 // LogMiddleware adds a logger using [slogutil.ContextWithLogger] and logs the
@@ -45,8 +46,11 @@ func (mw *LogMiddleware) Wrap(h http.Handler) (wrapped http.Handler) {
 
 		l.Log(ctx, mw.lvl, "started")
 		defer func() {
-			elapsed := time.Since(startTime)
-			l.Log(ctx, mw.lvl, "finished", "code", rw.code, "elapsed", elapsed.String())
+			// TODO(a.garipov):  Augment our JSON handler to use
+			// [time.Duration.String] automatically?
+			l.Log(ctx, mw.lvl, "finished", "code", rw.code, "elapsed", timeutil.Duration{
+				Duration: time.Since(startTime),
+			})
 		}()
 
 		h.ServeHTTP(rw, r)

netutil/httputil/logmw_test.go

@@ -54,6 +54,10 @@ func TestLogMiddleware(t *testing.T) {
 
 		if i == 1 {
 			assert.Equal(t, float64(http.StatusOK), obj["code"])
+
+			// Make sure that the "elapsed" attribute is printed consistently.
+			elapsedStr := testutil.RequireTypeAssert[string](t, obj["elapsed"])
+			assert.Regexp(t, `[0-9.]+[a-zµ]+`, elapsedStr)
 		}
 	}
 }