Reduce number of buckets for auto-generated metrics (#780)

For the auto-generated histogram metrics, we use a large number of
buckets. The largest bucket captures values up to 50 quintillion.

However, having a large number of buckets results in a significant size for exported metrics,
even if they carry 0 data (as most buckets will have 0
values). This leads to: (1) higher costs for the user (e.g., Google Cloud
monitoring charges you based on the volume of metrics exported), and (2)
increased system load due to handling large metrics data.

This PR reduces the number of buckets to capture values up to 5 billion
(5e9),
which seems reasonable in practice. E.g., auto-generated metrics using
these buckets:
1) http_request_latency_micros - even if this is 10 minutes, the value
   is still 6e7
2) http_request_bytes_received - http request size of more than 5 GB seem
   rare
3) http_request_bytes_returned - http response size of more than 5 GB
   seem rare
4) serviceweaver_method_latency_micros - component method execution of
   more than 1.3 hours seem rare
5) serviceweaver_method_bytes_request - request size of more than 5 GB
   seem rare
6) serviceweaver_method_bytes_reply - response size of more than 5 GB
   seem rare

godeps.txt

@@ -4,6 +4,7 @@ github.com/ServiceWeaver/weaver
     errors
     fmt
     github.com/ServiceWeaver/weaver/internal/control
+    github.com/ServiceWeaver/weaver/internal/metrics
     github.com/ServiceWeaver/weaver/internal/reflection
     github.com/ServiceWeaver/weaver/internal/weaver
     github.com/ServiceWeaver/weaver/metrics
@@ -315,8 +316,7 @@ github.com/ServiceWeaver/weaver/internal/heap
     container/heap
 github.com/ServiceWeaver/weaver/internal/metrics
     context
-    github.com/ServiceWeaver/weaver/runtime/codegen
-    github.com/ServiceWeaver/weaver/runtime/logging
+    fmt
     github.com/ServiceWeaver/weaver/runtime/metrics
     strings
     sync
@@ -386,8 +386,8 @@ github.com/ServiceWeaver/weaver/internal/status
     flag
     fmt
     github.com/ServiceWeaver/weaver/internal/files
+    github.com/ServiceWeaver/weaver/internal/metrics
     github.com/ServiceWeaver/weaver/internal/traceio
-    github.com/ServiceWeaver/weaver/runtime/codegen
     github.com/ServiceWeaver/weaver/runtime/colors
     github.com/ServiceWeaver/weaver/runtime/logging
     github.com/ServiceWeaver/weaver/runtime/metrics
@@ -742,6 +742,7 @@ github.com/ServiceWeaver/weaver/runtime/codegen
     errors
     fmt
     github.com/ServiceWeaver/weaver/internal/config
+    github.com/ServiceWeaver/weaver/internal/metrics
     github.com/ServiceWeaver/weaver/metrics
     github.com/ServiceWeaver/weaver/runtime
     github.com/ServiceWeaver/weaver/runtime/protos
@@ -875,6 +876,7 @@ github.com/ServiceWeaver/weaver/runtime/protomsg
     encoding/binary
     errors
     fmt
+    github.com/ServiceWeaver/weaver/internal/metrics
     github.com/ServiceWeaver/weaver/metrics
     github.com/ServiceWeaver/weaver/runtime/codegen
     google.golang.org/protobuf/proto

http.go

@@ -21,6 +21,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	imetrics "github.com/ServiceWeaver/weaver/internal/metrics"
 	"github.com/ServiceWeaver/weaver/metrics"
 	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 )
@@ -58,17 +59,17 @@ var (
 	httpRequestLatencyMicros = metrics.NewHistogramMap[httpLabels](
 		"serviceweaver_http_request_latency_micros",
 		"Duration, in microseconds, of HTTP request execution",
-		metrics.NonNegativeBuckets,
+		imetrics.GeneratedBuckets,
 	)
 	httpRequestBytesReceived = metrics.NewHistogramMap[httpLabels](
 		"serviceweaver_http_request_bytes_received",
 		"Number of bytes received by HTTP request handlers",
-		metrics.NonNegativeBuckets,
+		imetrics.GeneratedBuckets,
 	)
 	httpRequestBytesReturned = metrics.NewHistogramMap[httpLabels](
 		"serviceweaver_http_request_bytes_returned",
 		"Number of bytes returned by HTTP request handlers",
-		metrics.NonNegativeBuckets,
+		imetrics.GeneratedBuckets,
 	)
 )
 

internal/metrics/generated.go

@@ -0,0 +1,43 @@
+// Copyright 2024 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 metrics
+
+// Names of automatically populated metrics.
+const (
+	MethodCountsName       = "serviceweaver_method_count"
+	MethodErrorsName       = "serviceweaver_method_error_count"
+	MethodLatenciesName    = "serviceweaver_method_latency_micros"
+	MethodBytesRequestName = "serviceweaver_method_bytes_request"
+	MethodBytesReplyName   = "serviceweaver_method_bytes_reply"
+)
+
+// GeneratedBuckets provides rounded bucket boundaries for histograms
+// that will only store non-negative values.
+//
+// Note that these buckets are intended to be used only by the metrics generated
+// by the weaver runtime.
+var GeneratedBuckets = []float64{
+	// Adjacent buckets differ from each other by 2x or 2.5x.
+	1, 2, 5,
+	10, 20, 50,
+	100, 200, 500,
+	1000, 2000, 5000,
+	10000, 20000, 50000,
+	100000, 200000, 500000,
+	1000000, 2000000, 5000000,
+	10000000, 20000000, 50000000,
+	100000000, 200000000, 500000000,
+	1000000000, 2000000000, 5000000000, // i.e., 5e9
+}

internal/metrics/stats.go

@@ -16,12 +16,11 @@ package metrics
 
 import (
 	"context"
+	"fmt"
 	"strings"
 	"sync"
 	"time"
 
-	"github.com/ServiceWeaver/weaver/runtime/codegen"
-	"github.com/ServiceWeaver/weaver/runtime/logging"
 	"github.com/ServiceWeaver/weaver/runtime/metrics"
 )
 
@@ -154,7 +153,7 @@ func (s *StatsProcessor) getSnapshot(snapshot []*metrics.MetricSnapshot) {
 		var comp, method string
 		for k, v := range m.Labels {
 			if k == "component" {
-				comp = logging.ShortenComponent(v)
+				comp = shortenComponent(v)
 			} else if k == "method" {
 				method = v
 			}
@@ -176,13 +175,13 @@ func (s *StatsProcessor) getSnapshot(snapshot []*metrics.MetricSnapshot) {
 		// Aggregate stats within a bucket, based on metric values from different
 		// replicas for the method.
 		switch m.Name {
-		case codegen.MethodCountsName:
+		case MethodCountsName:
 			bucket.calls += m.Value
-		case codegen.MethodBytesReplyName:
+		case MethodBytesReplyName:
 			bucket.kbSent += m.Value / 1024 // B to KB
-		case codegen.MethodBytesRequestName:
+		case MethodBytesRequestName:
 			bucket.kbRecvd += m.Value / 1024 // B to KB
-		case codegen.MethodLatenciesName:
+		case MethodLatenciesName:
 			bucket.latencyMs += m.Value / 1000 // µs to ms
 
 			var count uint64
@@ -293,3 +292,22 @@ func (s *statsMethod) computeStatsStatusz(startTime time.Time) methodStatuszInfo
 	}
 	return result
 }
+
+// shortenComponent shortens the given component name to be of the format
+// <pkg>.<IfaceType>. (Recall that the full component name is of the format
+// <path1>/<path2>/.../<pathN>/<IfaceType>.)
+//
+// TODO(rgrandl): To avoid cyclic dependencies, we have created a local copy of the
+// logging.ShortenComponent method. Consider moving logging.ShortenComponent to a
+// different package instead.
+func shortenComponent(component string) string {
+	parts := strings.Split(component, "/")
+	switch len(parts) {
+	case 0: // should never happen
+		return "nil"
+	case 1:
+		return parts[0]
+	default:
+		return fmt.Sprintf("%s.%s", parts[len(parts)-2], parts[len(parts)-1])
+	}
+}

internal/status/dashboard.go

@@ -28,8 +28,8 @@ import (
 	"strings"
 	"time"
 
+	metrics2 "github.com/ServiceWeaver/weaver/internal/metrics"
 	"github.com/ServiceWeaver/weaver/internal/traceio"
-	"github.com/ServiceWeaver/weaver/runtime/codegen"
 	"github.com/ServiceWeaver/weaver/runtime/logging"
 	"github.com/ServiceWeaver/weaver/runtime/metrics"
 	"github.com/ServiceWeaver/weaver/runtime/perfetto"
@@ -267,7 +267,7 @@ func computeTraffic(status *Status, metrics []*protos.MetricSnapshot) []edge {
 	}
 	byPair := map[pair]int{}
 	for _, metric := range metrics {
-		if metric.Name != codegen.MethodCountsName {
+		if metric.Name != metrics2.MethodCountsName {
 			continue
 		}
 		call := pair{

runtime/codegen/metrics.go

@@ -17,42 +17,34 @@ package codegen
 import (
 	"time"
 
+	imetrics "github.com/ServiceWeaver/weaver/internal/metrics"
 	"github.com/ServiceWeaver/weaver/metrics"
 )
 
-// Names of automatically populated metrics.
-const (
-	MethodCountsName       = "serviceweaver_method_count"
-	MethodErrorsName       = "serviceweaver_method_error_count"
-	MethodLatenciesName    = "serviceweaver_method_latency_micros"
-	MethodBytesRequestName = "serviceweaver_method_bytes_request"
-	MethodBytesReplyName   = "serviceweaver_method_bytes_reply"
-)
-
 var (
 	// The following metrics are automatically populated for the user.
 	methodCounts = metrics.NewCounterMap[MethodLabels](
-		MethodCountsName,
+		imetrics.MethodCountsName,
 		"Count of Service Weaver component method invocations",
 	)
 	methodErrors = metrics.NewCounterMap[MethodLabels](
-		MethodErrorsName,
+		imetrics.MethodErrorsName,
 		"Count of Service Weaver component method invocations that result in an error",
 	)
 	methodLatencies = metrics.NewHistogramMap[MethodLabels](
-		MethodLatenciesName,
+		imetrics.MethodLatenciesName,
 		"Duration, in microseconds, of Service Weaver component method execution",
-		metrics.NonNegativeBuckets,
+		imetrics.GeneratedBuckets,
 	)
 	methodBytesRequest = metrics.NewHistogramMap[MethodLabels](
-		MethodBytesRequestName,
+		imetrics.MethodBytesRequestName,
 		"Number of bytes in Service Weaver component method requests",
-		metrics.NonNegativeBuckets,
+		imetrics.GeneratedBuckets,
 	)
 	methodBytesReply = metrics.NewHistogramMap[MethodLabels](
-		MethodBytesReplyName,
+		imetrics.MethodBytesReplyName,
 		"Number of bytes in Service Weaver component method replies",
-		metrics.NonNegativeBuckets,
+		imetrics.GeneratedBuckets,
 	)
 )
 

runtime/protomsg/handler.go

@@ -24,6 +24,7 @@ import (
 	"runtime/debug"
 	"time"
 
+	imetrics "github.com/ServiceWeaver/weaver/internal/metrics"
 	"github.com/ServiceWeaver/weaver/metrics"
 	"google.golang.org/protobuf/proto"
 )
@@ -40,17 +41,17 @@ var (
 	httpRequestLatencyMicros = metrics.NewHistogramMap[handlerLabels](
 		"serviceweaver_system_http_request_latency_micros",
 		"Duration, in microseconds, of Service Weaver HTTP request execution",
-		metrics.NonNegativeBuckets,
+		imetrics.GeneratedBuckets,
 	)
 	httpRequestBytesReceived = metrics.NewHistogramMap[handlerLabels](
 		"serviceweaver_system_http_request_bytes_received",
 		"Number of bytes received by Service Weaver HTTP request handlers",
-		metrics.NonNegativeBuckets,
+		imetrics.GeneratedBuckets,
 	)
 	httpRequestBytesReturned = metrics.NewHistogramMap[handlerLabels](
 		"serviceweaver_system_http_request_bytes_returned",
 		"Number of bytes returned by Service Weaver HTTP request handlers",
-		metrics.NonNegativeBuckets,
+		imetrics.GeneratedBuckets,
 	)
 )