google.golang.org/genproto/googleapis/api v0.0.0-20240826202546-f6391c0de4c7: metric.MetricDescriptor

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify google.golang.org/genproto/googleapis/api/metric.MetricDescriptor in pkg:golang/google.golang.org/genproto/googleapis/api@v0.0.0-20240826202546-f6391c0de4c7
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/google.golang.org/genproto/googleapis/api@v0.0.0-20240826202546-f6391c0de4c7
Demonstrate these symbols/APIs:
  - google.golang.org/genproto/googleapis/api/metric.MetricDescriptor

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:c088eaccc4819aa8eaf386ba587385b3525aba3896d6bb36d9ad1d988dfab1c8","contract":["MetricDescriptor struct fields and getter methods return configured attributes including Name, Type, MetricKind, ValueType, Unit, Description, DisplayName, Labels, and MonitoredResourceTypes","Nil safety — GetName, GetType, GetUnit, GetDescription, GetDisplayName, GetMetricKind, GetValueType, GetLabels, GetMetadata, and GetMonitoredResourceTypes on nil *MetricDescriptor return zero values without panicking","Protobuf binary serialization and deserialization preserves MetricDescriptor fields exactly","Protobuf JSON serialization and deserialization preserves MetricDescriptor structure and values","Nested LabelDescriptor within MetricDescriptor correctly specifies label schema","Reset clears MetricDescriptor fields back to zero default values"],"goal":"verify google.golang.org/genproto/googleapis/api/metric.MetricDescriptor in pkg:golang/google.golang.org/genproto/googleapis/api@v0.0.0-20240826202546-f6391c0de4c7","kind":"HOW","packages":["pkg:golang/google.golang.org/genproto/googleapis/api@v0.0.0-20240826202546-f6391c0de4c7"],"schemaVersion":1,"symbols":["google.golang.org/genproto/googleapis/api/metric.MetricDescriptor"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/google.golang.org/genproto/googleapis/api@v0.0.0-20240826202546-f6391c0de4c7"],"schemaVersion":1,"subject":"pkg:golang/google.golang.org/genproto/googleapis/api@v0.0.0-20240826202546-f6391c0de4c7","symbols":["google.golang.org/genproto/googleapis/api/metric.MetricDescriptor"],"verifierAdapter":"golang@1"}

module example.com/metricdescriptor

go 1.22.0

require (
	google.golang.org/genproto/googleapis/api v0.0.0-20240826202546-f6391c0de4c7
	google.golang.org/protobuf v1.34.2
)

github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
google.golang.org/genproto/googleapis/api v0.0.0-20240826202546-f6391c0de4c7 h1:YcyjlL1PRr2Q17/I0dPk2JmYS5CDXfcdb2Z3YRioEbw=
google.golang.org/genproto/googleapis/api v0.0.0-20240826202546-f6391c0de4c7/go.mod h1:OCdP9MfskevB/rbYvHTsXTtKC+3bHWajPdoKgjcYkfo=
google.golang.org/protobuf v1.34.2 h1:6xV6lTsCfpGD21XK49h7MhtcApnLqkfYgPcdHftf6hg=
google.golang.org/protobuf v1.34.2/go.mod h1:qYOHts0dSfpeUzUFpOMr/WGzszTmLH+DiWniOlNbLDw=

package main

import (
	"fmt"

	"google.golang.org/genproto/googleapis/api/label"
	"google.golang.org/genproto/googleapis/api/metric"
	"google.golang.org/protobuf/encoding/protojson"
	"google.golang.org/protobuf/proto"
)

func main() {
	// Define a custom metric descriptor for measuring request latency
	descriptor := &metric.MetricDescriptor{
		Name:        "projects/example-project/metricDescriptors/custom.googleapis.com/http/server/latency",
		Type:        "custom.googleapis.com/http/server/latency",
		MetricKind:  metric.MetricDescriptor_GAUGE,
		ValueType:   metric.MetricDescriptor_DOUBLE,
		Unit:        "ms",
		Description: "The latency of HTTP requests processed by the server",
		DisplayName: "HTTP Request Latency",
		Labels: []*label.LabelDescriptor{
			{
				Key:         "response_code",
				ValueType:   label.LabelDescriptor_INT64,
				Description: "HTTP status code returned to the client",
			},
			{
				Key:         "environment",
				ValueType:   label.LabelDescriptor_STRING,
				Description: "Deployment environment (e.g. production, staging)",
			},
		},
		MonitoredResourceTypes: []string{
			"generic_task",
			"gce_instance",
		},
	}

	fmt.Printf("Metric Descriptor Type: %s\n", descriptor.GetType())
	fmt.Printf("Metric Kind: %s, Value Type: %s, Unit: %s\n",
		descriptor.GetMetricKind().String(),
		descriptor.GetValueType().String(),
		descriptor.GetUnit(),
	)
	fmt.Printf("Configured Labels: %d\n", len(descriptor.GetLabels()))

	// Protobuf JSON serialization
	jsonBytes, err := protojson.Marshal(descriptor)
	if err != nil {
		fmt.Printf("JSON marshal error: %v\n", err)
		return
	}
	fmt.Printf("Serialized JSON: %s\n", string(jsonBytes))

	// Protobuf binary wire serialization
	wireBytes, err := proto.Marshal(descriptor)
	if err != nil {
		fmt.Printf("Binary marshal error: %v\n", err)
		return
	}
	fmt.Printf("Serialized binary size: %d bytes\n", len(wireBytes))
}

{
  "schemaVersion": 1,
  "goal": "verify google.golang.org/genproto/googleapis/api/metric.MetricDescriptor in pkg:golang/google.golang.org/genproto/googleapis/api@v0.0.0-20240826202546-f6391c0de4c7",
  "kind": "HOW",
  "packages": [
    "pkg:golang/google.golang.org/genproto/googleapis/api@v0.0.0-20240826202546-f6391c0de4c7"
  ],
  "symbols": [
    "google.golang.org/genproto/googleapis/api/metric.MetricDescriptor"
  ]
}

package main

import (
	"fmt"
	"os"

	"google.golang.org/genproto/googleapis/api/label"
	"google.golang.org/genproto/googleapis/api/metric"
	"google.golang.org/protobuf/encoding/protojson"
	"google.golang.org/protobuf/proto"
)

func main() {
	// Assertion 1: MetricDescriptor field initialization and getter methods return configured attributes
	{
		desc := &metric.MetricDescriptor{
			Name:        "projects/example-project/metricDescriptors/custom.googleapis.com/invoice/processing_time",
			Type:        "custom.googleapis.com/invoice/processing_time",
			MetricKind:  metric.MetricDescriptor_GAUGE,
			ValueType:   metric.MetricDescriptor_DOUBLE,
			Unit:        "ms",
			Description: "Processing time for invoice operations",
			DisplayName: "Invoice Processing Time",
			Labels: []*label.LabelDescriptor{
				{
					Key:         "environment",
					ValueType:   label.LabelDescriptor_STRING,
					Description: "Deployment environment",
				},
			},
			MonitoredResourceTypes: []string{
				"generic_task",
			},
		}

		if desc.GetName() != "projects/example-project/metricDescriptors/custom.googleapis.com/invoice/processing_time" {
			fmt.Fprintf(os.Stderr, "FAIL: GetName() mismatch: got %q\n", desc.GetName())
			os.Exit(1)
		}
		if desc.GetType() != "custom.googleapis.com/invoice/processing_time" {
			fmt.Fprintf(os.Stderr, "FAIL: GetType() mismatch: got %q\n", desc.GetType())
			os.Exit(1)
		}
		if desc.GetMetricKind() != metric.MetricDescriptor_GAUGE {
			fmt.Fprintf(os.Stderr, "FAIL: GetMetricKind() mismatch: got %v\n", desc.GetMetricKind())
			os.Exit(1)
		}
		if desc.GetValueType() != metric.MetricDescriptor_DOUBLE {
			fmt.Fprintf(os.Stderr, "FAIL: GetValueType() mismatch: got %v\n", desc.GetValueType())
			os.Exit(1)
		}
		if desc.GetUnit() != "ms" {
			fmt.Fprintf(os.Stderr, "FAIL: GetUnit() mismatch: got %q\n", desc.GetUnit())
			os.Exit(1)
		}
		if desc.GetDescription() != "Processing time for invoice operations" {
			fmt.Fprintf(os.Stderr, "FAIL: GetDescription() mismatch: got %q\n", desc.GetDescription())
			os.Exit(1)
		}
		if desc.GetDisplayName() != "Invoice Processing Time" {
			fmt.Fprintf(os.Stderr, "FAIL: GetDisplayName() mismatch: got %q\n", desc.GetDisplayName())
			os.Exit(1)
		}
		if len(desc.GetLabels()) != 1 || desc.GetLabels()[0].GetKey() != "environment" {
			fmt.Fprintf(os.Stderr, "FAIL: GetLabels() mismatch\n")
			os.Exit(1)
		}
		if len(desc.GetMonitoredResourceTypes()) != 1 || desc.GetMonitoredResourceTypes()[0] != "generic_task" {
			fmt.Fprintf(os.Stderr, "FAIL: GetMonitoredResourceTypes() mismatch\n")
			os.Exit(1)
		}
	}

	// Assertion 2: Nil safety — getters on nil *MetricDescriptor return zero values without panicking
	{
		var nilDesc *metric.MetricDescriptor
		if nilDesc.GetName() != "" {
			fmt.Fprintf(os.Stderr, "FAIL: nil GetName() expected empty string, got %q\n", nilDesc.GetName())
			os.Exit(1)
		}
		if nilDesc.GetType() != "" {
			fmt.Fprintf(os.Stderr, "FAIL: nil GetType() expected empty string, got %q\n", nilDesc.GetType())
			os.Exit(1)
		}
		if nilDesc.GetUnit() != "" {
			fmt.Fprintf(os.Stderr, "FAIL: nil GetUnit() expected empty string, got %q\n", nilDesc.GetUnit())
			os.Exit(1)
		}
		if nilDesc.GetDescription() != "" {
			fmt.Fprintf(os.Stderr, "FAIL: nil GetDescription() expected empty string, got %q\n", nilDesc.GetDescription())
			os.Exit(1)
		}
		if nilDesc.GetDisplayName() != "" {
			fmt.Fprintf(os.Stderr, "FAIL: nil GetDisplayName() expected empty string, got %q\n", nilDesc.GetDisplayName())
			os.Exit(1)
		}
		if nilDesc.GetMetricKind() != metric.MetricDescriptor_METRIC_KIND_UNSPECIFIED {
			fmt.Fprintf(os.Stderr, "FAIL: nil GetMetricKind() expected METRIC_KIND_UNSPECIFIED, got %v\n", nilDesc.GetMetricKind())
			os.Exit(1)
		}
		if nilDesc.GetValueType() != metric.MetricDescriptor_VALUE_TYPE_UNSPECIFIED {
			fmt.Fprintf(os.Stderr, "FAIL: nil GetValueType() expected VALUE_TYPE_UNSPECIFIED, got %v\n", nilDesc.GetValueType())
			os.Exit(1)
		}
		if nilDesc.GetLabels() != nil {
			fmt.Fprintf(os.Stderr, "FAIL: nil GetLabels() expected nil, got %v\n", nilDesc.GetLabels())
			os.Exit(1)
		}
		if nilDesc.GetMetadata() != nil {
			fmt.Fprintf(os.Stderr, "FAIL: nil GetMetadata() expected nil, got %v\n", nilDesc.GetMetadata())
			os.Exit(1)
		}
		if nilDesc.GetMonitoredResourceTypes() != nil {
			fmt.Fprintf(os.Stderr, "FAIL: nil GetMonitoredResourceTypes() expected nil, got %v\n", nilDesc.GetMonitoredResourceTypes())
			os.Exit(1)
		}
	}

	// Assertion 3: Protobuf binary serialization and deserialization preserves MetricDescriptor fields exactly
	{
		orig := &metric.MetricDescriptor{
			Name:        "projects/example-project/metricDescriptors/custom.googleapis.com/network/bandwidth",
			Type:        "custom.googleapis.com/network/bandwidth",
			MetricKind:  metric.MetricDescriptor_CUMULATIVE,
			ValueType:   metric.MetricDescriptor_INT64,
			Unit:        "By",
			Description: "Total network egress bytes",
			DisplayName: "Network Egress Bytes",
			Labels: []*label.LabelDescriptor{
				{
					Key:         "interface",
					ValueType:   label.LabelDescriptor_STRING,
					Description: "Network interface identifier",
				},
			},
			MonitoredResourceTypes: []string{"gce_instance"},
		}

		wire, err := proto.Marshal(orig)
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: proto.Marshal failed: %v\n", err)
			os.Exit(1)
		}

		decoded := &metric.MetricDescriptor{}
		if err := proto.Unmarshal(wire, decoded); err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: proto.Unmarshal failed: %v\n", err)
			os.Exit(1)
		}

		if !proto.Equal(orig, decoded) {
			fmt.Fprintf(os.Stderr, "FAIL: decoded proto message does not equal original\n")
			os.Exit(1)
		}
		if decoded.GetType() != orig.GetType() || decoded.GetMetricKind() != orig.GetMetricKind() || decoded.GetValueType() != orig.GetValueType() {
			fmt.Fprintf(os.Stderr, "FAIL: decoded fields mismatch\n")
			os.Exit(1)
		}
	}

	// Assertion 4: Protobuf JSON serialization and deserialization preserves MetricDescriptor structure and values
	{
		orig := &metric.MetricDescriptor{
			Name:        "projects/example-project/metricDescriptors/custom.googleapis.com/tasks/queue_size",
			Type:        "custom.googleapis.com/tasks/queue_size",
			MetricKind:  metric.MetricDescriptor_GAUGE,
			ValueType:   metric.MetricDescriptor_INT64,
			Unit:        "1",
			Description: "Current number of items in the queue",
			DisplayName: "Queue Size",
		}

		jsonBytes, err := protojson.Marshal(orig)
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: protojson.Marshal failed: %v\n", err)
			os.Exit(1)
		}

		unmarshaled := &metric.MetricDescriptor{}
		if err := protojson.Unmarshal(jsonBytes, unmarshaled); err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: protojson.Unmarshal failed: %v\n", err)
			os.Exit(1)
		}

		if unmarshaled.GetType() != "custom.googleapis.com/tasks/queue_size" ||
			unmarshaled.GetMetricKind() != metric.MetricDescriptor_GAUGE ||
			unmarshaled.GetValueType() != metric.MetricDescriptor_INT64 ||
			unmarshaled.GetUnit() != "1" {
			fmt.Fprintf(os.Stderr, "FAIL: protojson unmarshaled fields mismatch\n")
			os.Exit(1)
		}
	}

	// Assertion 5: Nested LabelDescriptor within MetricDescriptor correctly specifies label schema
	{
		labelDesc := &label.LabelDescriptor{
			Key:         "region",
			ValueType:   label.LabelDescriptor_STRING,
			Description: "Geographic cloud region",
		}

		desc := &metric.MetricDescriptor{
			Type:   "custom.googleapis.com/api/errors",
			Labels: []*label.LabelDescriptor{labelDesc},
		}

		if len(desc.GetLabels()) != 1 {
			fmt.Fprintf(os.Stderr, "FAIL: expected 1 label, got %d\n", len(desc.GetLabels()))
			os.Exit(1)
		}
		if desc.GetLabels()[0].GetKey() != "region" || desc.GetLabels()[0].GetValueType() != label.LabelDescriptor_STRING {
			fmt.Fprintf(os.Stderr, "FAIL: label descriptor content mismatch\n")
			os.Exit(1)
		}
	}

	// Assertion 6: Reset clears MetricDescriptor fields back to zero default values
	{
		desc := &metric.MetricDescriptor{
			Name:        "projects/example/metricDescriptors/test",
			Type:        "custom.googleapis.com/test",
			MetricKind:  metric.MetricDescriptor_GAUGE,
			ValueType:   metric.MetricDescriptor_DOUBLE,
			Unit:        "s",
			Description: "Test metric",
			DisplayName: "Test",
		}

		desc.Reset()
		if desc.GetName() != "" || desc.GetType() != "" || desc.GetUnit() != "" || desc.GetDescription() != "" || desc.GetDisplayName() != "" {
			fmt.Fprintf(os.Stderr, "FAIL: expected empty fields after Reset()\n")
			os.Exit(1)
		}
		if desc.GetMetricKind() != metric.MetricDescriptor_METRIC_KIND_UNSPECIFIED || desc.GetValueType() != metric.MetricDescriptor_VALUE_TYPE_UNSPECIFIED {
			fmt.Fprintf(os.Stderr, "FAIL: expected unspecified enum values after Reset()\n")
			os.Exit(1)
		}
	}

	fmt.Println("PASS: google.golang.org/genproto/googleapis/api/metric.MetricDescriptor contract passed")
}