github.com/googleapis/gax-go/v2 v2.24.0: gax.Invoke, gax.OnCodes, gax.Version

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 pkg:golang/github.com/googleapis/gax-go/v2@v2.24.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/googleapis/gax-go/v2@v2.24.0
Demonstrate these symbols/APIs:
  - gax.Invoke
  - gax.OnCodes
  - gax.Version
  - gax.XGoogHeader

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:f4673d86b5d9aa73823b85e65240914d95ee35f39a018031040328fbb73516fe","contract":["gax.Version returns 2.24.0","gax.XGoogHeader formats key-value pairs into slash-delimited header values","gax.Invoke retries on configured gRPC status codes until success"],"goal":"verify pkg:golang/github.com/googleapis/gax-go/v2@v2.24.0","kind":"HOW","packages":["pkg:golang/github.com/googleapis/gax-go/v2@v2.24.0"],"schemaVersion":1,"symbols":["gax.Invoke","gax.OnCodes","gax.Version","gax.XGoogHeader"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","packageManagerVersion":"1.26.6","runtime":"go","runtimeVersion":"1.26.6","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/googleapis/gax-go/v2@v2.24.0"],"schemaVersion":1,"subject":"pkg:golang/github.com/googleapis/gax-go/v2@v2.24.0","symbols":["gax.Invoke","gax.OnCodes","gax.Version","gax.XGoogHeader"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require (
	github.com/googleapis/gax-go/v2 v2.24.0
	google.golang.org/grpc v1.82.1
)

require (
	github.com/cespare/xxhash/v2 v2.3.0 // indirect
	github.com/go-logr/logr v1.4.3 // indirect
	github.com/go-logr/stdr v1.2.2 // indirect
	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
	go.opentelemetry.io/otel v1.44.0 // indirect
	go.opentelemetry.io/otel/metric v1.44.0 // indirect
	go.opentelemetry.io/otel/trace v1.44.0 // indirect
	golang.org/x/net v0.56.0 // indirect
	golang.org/x/sys v0.47.0 // indirect
	golang.org/x/text v0.40.0 // indirect
	google.golang.org/api v0.288.0 // indirect
	google.golang.org/genproto/googleapis/rpc v0.0.0-20260715232425-e75dac1f907d // indirect
	google.golang.org/protobuf v1.36.11 // indirect
)

github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
github.com/go-logr/logr v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=
github.com/go-logr/logr v1.4.3/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
github.com/golang/protobuf v1.5.4 h1:i7eJL8qZTpSEXOPTxNKhASYpMn+8e5Q6AdndVa1dWek=
github.com/golang/protobuf v1.5.4/go.mod h1:lnTiLA8Wa4RWRcIUkrtSVa5nRhsEGBg48fD6rSs7xps=
github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
github.com/googleapis/gax-go/v2 v2.24.0 h1:myMaPYyF9MecEmvQqMqomIwn9t/4KCZN9qnwsS76wlg=
github.com/googleapis/gax-go/v2 v2.24.0/go.mod h1:IaTHBDd7NHxSCiu0vEs8pQZu4dGZrWwuSoxCnk16OFM=
github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
go.opentelemetry.io/auto/sdk v1.2.1 h1:jXsnJ4Lmnqd11kwkBV2LgLoFMZKizbCi5fNZ/ipaZ64=
go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=
go.opentelemetry.io/otel v1.44.0 h1:JjwHmHpA4iZ3wBxluu2fbbE7j4kqlE8jXyAyPXH7HqU=
go.opentelemetry.io/otel v1.44.0/go.mod h1:BMgjTHL9WPRlRjL2oZCBTL4whCGtXch2H4BhOPIAyYc=
go.opentelemetry.io/otel/metric v1.44.0 h1:1w0gILTcHdr3YI+ixLyjemwrVnsMURbTZFrSYCdDdmc=
go.opentelemetry.io/otel/metric v1.44.0/go.mod h1:8O7hanEPBNgEMmybD3s2VBKcgWOCsA6tzHBPODAiquo=
go.opentelemetry.io/otel/sdk v1.44.0 h1:nHYwb9lK+fJPU/dnT6s7W7Z8itMWyqrnVfbheVYrZ58=
go.opentelemetry.io/otel/sdk v1.44.0/go.mod h1:Osuydd3Se74nqjAKxid74N5eC+jfEqfTegHRnq58oK0=
go.opentelemetry.io/otel/sdk/metric v1.44.0 h1:3LlKgI+VjbVsjNRFZJZAJ30WjXC5VkNRks6si09iEfI=
go.opentelemetry.io/otel/sdk/metric v1.44.0/go.mod h1:5B5pMARnXxKhltooO4xUuCBorl65a4EpnTalObqOigA=
go.opentelemetry.io/otel/trace v1.44.0 h1:jxF5CsGYCe74MCRx2X4g7WsY/VBKRqqpNvXlX/6gtIk=
go.opentelemetry.io/otel/trace v1.44.0/go.mod h1:oLl1jrMQAVo6v3GAggN+1VH9VIz9iUSvW53sW1Q8PIE=
golang.org/x/net v0.56.0 h1:Rw8j/hFzGvJUZwNBXnAtf5sVDVt+65SK2C7IxCxZt5o=
golang.org/x/net v0.56.0/go.mod h1:D3Ku6r+V6JROoZK144D2XfMHFcMq/0zSfLelVTCFKec=
golang.org/x/sys v0.47.0 h1:o7XGOvZQCADBQQ4Y7VNq2dRWQR7JmOUW8Kxx4ZsNgWs=
golang.org/x/sys v0.47.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
golang.org/x/text v0.40.0 h1:Ub2Z6/xjgF1WrYQz2nuITOEegKFtiIy+rieRJ5lHZKs=
golang.org/x/text v0.40.0/go.mod h1:hpnzDAfGV753zIKo+wk3u1bVKCGPbrnF7+7LBF/UHVY=
gonum.org/v1/gonum v0.17.0 h1:VbpOemQlsSMrYmn7T2OUvQ4dqxQXU+ouZFQsZOx50z4=
gonum.org/v1/gonum v0.17.0/go.mod h1:El3tOrEuMpv2UdMrbNlKEh9vd86bmQ6vqIcDwxEOc1E=
google.golang.org/api v0.288.0 h1:glhO/J88obKP5I269W3hB73dvBKrjU56ZfmNlNXpgTU=
google.golang.org/api v0.288.0/go.mod h1:lM2kYRzYUCBY91P9h6VF1PYmvhxii3O5hji37qRvIcY=
google.golang.org/genproto v0.0.0-20260715232425-e75dac1f907d h1:C9v1o0/4quuhOAfmRXA2j+we0PqZIp8traLdeogF3Ms=
google.golang.org/genproto v0.0.0-20260715232425-e75dac1f907d/go.mod h1:Wz2wFJntZFmLGo7pLDXZ3wYk5hyc0Mb+SkHhDDXT+lU=
google.golang.org/genproto/googleapis/api v0.0.0-20260715232425-e75dac1f907d h1:QwnJwPte4XXAkhPu26LTDIahnsMSUV0kK8HkxbC+Pc4=
google.golang.org/genproto/googleapis/api v0.0.0-20260715232425-e75dac1f907d/go.mod h1:WRrQ7/7N19PypuT0fxLOL5Lq0waoiRri4FbtHDEKrGE=
google.golang.org/genproto/googleapis/rpc v0.0.0-20260715232425-e75dac1f907d h1:Jkpk39hlTZOIp3RbfvNX9R8Hv+Sw0X89nlU/xFOErsc=
google.golang.org/genproto/googleapis/rpc v0.0.0-20260715232425-e75dac1f907d/go.mod h1:4Hqkh8ycfw05ld/3BWL7rJOSfebL2Q+DVDeRgYgxUU8=
google.golang.org/grpc v1.82.1 h1:NnAxzGRA0677vCa4BUkOAnO5+FfQqVl9iUXeD0IqcGE=
google.golang.org/grpc v1.82.1/go.mod h1:yzTZ1TB1Z3SG+LIYaI+WiE8D5+PZ3ArnrSp8zF3+/ZA=
google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/github.com/googleapis/gax-go/v2@v2.24.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/googleapis/gax-go/v2@v2.24.0"
  ],
  "symbols": [
    "gax.Invoke",
    "gax.OnCodes",
    "gax.Version",
    "gax.XGoogHeader"
  ]
}

package main

import (
	"context"
	"fmt"
	"os"
	"time"

	"github.com/googleapis/gax-go/v2"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

func main() {
	// 1. gax.Version
	if gax.Version != "2.24.0" {
		fmt.Fprintf(os.Stderr, "expected gax.Version 2.24.0, got %s\n", gax.Version)
		os.Exit(1)
	}

	// 2. gax.XGoogHeader
	hdr := gax.XGoogHeader("gl-go", "1.26.6", "gapic", "2.24.0")
	if hdr != "gl-go/1.26.6 gapic/2.24.0" {
		fmt.Fprintf(os.Stderr, "unexpected header: %s\n", hdr)
		os.Exit(1)
	}

	// 3. gax.Invoke and gax.OnCodes
	var attempts int
	call := func(ctx context.Context, settings gax.CallSettings) error {
		attempts++
		if attempts < 3 {
			return status.Error(codes.Unavailable, "temporary failure")
		}
		return nil
	}

	bo := gax.Backoff{
		Initial:    time.Millisecond,
		Max:        10 * time.Millisecond,
		Multiplier: 2,
	}
	retryer := gax.OnCodes([]codes.Code{codes.Unavailable}, bo)

	ctx := context.Background()
	err := gax.Invoke(ctx, call, gax.WithRetry(func() gax.Retryer {
		return retryer
	}))
	if err != nil {
		fmt.Fprintf(os.Stderr, "unexpected Invoke error: %v\n", err)
		os.Exit(1)
	}
	if attempts != 3 {
		fmt.Fprintf(os.Stderr, "expected 3 attempts, got %d\n", attempts)
		os.Exit(1)
	}

	fmt.Println("All contract assertions passed.")
}