[Feature] Requests Bytes Counter (#1334)

Author: ajanikow

CHANGELOG.md

@@ -4,6 +4,7 @@
 - (Feature) AgencyCache Interface
 - (Feature) Agency Cache Poll EE Extension
 - (Feature) Metrics Counter
+- (Feature) Requests Bytes Counter
 
 ## [1.2.29](https://github.com/arangodb/kube-arangodb/tree/1.2.29) (2023-06-08)
 - (Maintenance) Add govulncheck to pipeline, update golangci-linter

pkg/util/arangod/conn/conn.executor.go

@@ -27,6 +27,8 @@ import (
 	"io"
 	"net/http"
 	"reflect"
+
+	"github.com/arangodb/kube-arangodb/pkg/util/metrics/nctx"
 )
 
 func NewExecutor[IN, OUT interface{}](conn Connection) Executor[IN, OUT] {
@@ -68,7 +70,7 @@ func (e executor[IN, OUT]) Execute(ctx context.Context, method string, endpoint
 
 	var out OUT
 
-	if err := json.NewDecoder(resp).Decode(&out); err != nil {
+	if err := json.NewDecoder(nctx.WithRequestReadBytes(ctx, resp)).Decode(&out); err != nil {
 		return nil, 0, err
 	}
 

pkg/util/metrics/nctx/counter.go

@@ -0,0 +1,45 @@
+//
+// DISCLAIMER
+//
+// Copyright 2023 ArangoDB GmbH, Cologne, Germany
+//
+// 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.
+//
+// Copyright holder is ArangoDB GmbH, Cologne, Germany
+//
+
+package nctx
+
+import (
+	"sync"
+)
+
+type Counter struct {
+	lock sync.Mutex
+
+	value uint64
+}
+
+func (c *Counter) Get() uint64 {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	return c.value
+}
+
+func (c *Counter) add(v uint64) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	c.value += v
+}

pkg/util/metrics/nctx/counter_request_read.go

@@ -0,0 +1,65 @@
+//
+// DISCLAIMER
+//
+// Copyright 2023 ArangoDB GmbH, Cologne, Germany
+//
+// 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.
+//
+// Copyright holder is ArangoDB GmbH, Cologne, Germany
+//
+
+package nctx
+
+import (
+	"context"
+	"io"
+)
+
+const RequestReadBytesKey Key = "operator.requestReadBytes"
+
+func (c *Counter) WithRequestReadBytes(ctx context.Context) context.Context {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+
+	return context.WithValue(ctx, RequestReadBytesKey, c)
+}
+
+type requestReadBytes struct {
+	c *Counter
+
+	in io.Reader
+}
+
+func (r requestReadBytes) Read(p []byte) (n int, err error) {
+	n, err = r.in.Read(p)
+	r.c.add(uint64(n))
+	return
+}
+
+func WithRequestReadBytes(ctx context.Context, reader io.Reader) io.Reader {
+	v := ctx.Value(RequestReadBytesKey)
+	if v == nil {
+		return reader
+	}
+
+	z, ok := v.(*Counter)
+	if !ok {
+		return reader
+	}
+
+	return requestReadBytes{
+		c:  z,
+		in: reader,
+	}
+}

pkg/util/metrics/nctx/counter_request_read_test.go

@@ -0,0 +1,53 @@
+//
+// DISCLAIMER
+//
+// Copyright 2023 ArangoDB GmbH, Cologne, Germany
+//
+// 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.
+//
+// Copyright holder is ArangoDB GmbH, Cologne, Germany
+//
+
+package nctx
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func counterRequestReadMock(t *testing.T, ctx context.Context, data io.Reader) int {
+	data = WithRequestReadBytes(ctx, data)
+	dz, err := io.ReadAll(data)
+	require.NoError(t, err)
+	return len(dz)
+}
+
+func Test_Counter_RequestRead(t *testing.T) {
+	data := make([]byte, 64)
+
+	var c Counter
+
+	t.Run("Read without wrapper", func(t *testing.T) {
+		require.EqualValues(t, 64, counterRequestReadMock(t, context.Background(), bytes.NewReader(data)))
+		require.EqualValues(t, 0, c.Get())
+	})
+
+	t.Run("Read with wrapper", func(t *testing.T) {
+		require.EqualValues(t, 64, counterRequestReadMock(t, c.WithRequestReadBytes(context.Background()), bytes.NewReader(data)))
+		require.EqualValues(t, 64, c.Get())
+	})
+}

pkg/util/metrics/nctx/interface.go

@@ -0,0 +1,29 @@
+//
+// DISCLAIMER
+//
+// Copyright 2023 ArangoDB GmbH, Cologne, Germany
+//
+// 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.
+//
+// Copyright holder is ArangoDB GmbH, Cologne, Germany
+//
+
+package nctx
+
+import "context"
+
+type Key string
+
+type With interface {
+	With(ctx context.Context) context.Context
+}