---

name: go-modules description: Go modules and dependency management sasmp_version: "1.3.0" bonded_agent: 01-go-fundamentals bond_type: SECONDARY_BOND

Go Modules Skill

Master Go module system and dependency management.

Overview

Complete guide for Go modules including versioning, private modules, vendoring, and dependency updates.

Parameters

Core Topics

Module Initialization

Copy# Initialize new module
go mod init github.com/myorg/myapp

# Download dependencies
go mod download

# Cleanup unused dependencies
go mod tidy

# Verify dependencies
go mod verify

go.mod Structure

Copymodule github.com/myorg/myapp

go 1.22

require (
    github.com/gin-gonic/gin v1.9.1
    github.com/jmoiron/sqlx v1.3.5
    go.uber.org/zap v1.26.0
)

require (
    // indirect dependencies auto-managed
    github.com/lib/pq v1.10.9 // indirect
)

Private Modules

Copy# Configure private module pattern
go env -w GOPRIVATE=github.com/myorg/*

# Use SSH for private repos
git config --global url."git@github.com:".insteadOf "https://github.com/"

# Or use access token
git config --global url."https://${GITHUB_TOKEN}@github.com/".insteadOf "https://github.com/"

Vendoring

Copy# Create vendor directory
go mod vendor

# Build with vendor
go build -mod=vendor ./...

# Verify vendor is in sync
go mod verify

Dependency Updates

Copy# List available updates
go list -m -u all

# Update specific dependency
go get github.com/gin-gonic/gin@latest

# Update all dependencies
go get -u ./...

# Update to specific version
go get github.com/gin-gonic/gin@v1.9.1

# Downgrade
go get github.com/gin-gonic/gin@v1.8.0

Replace Directives

Copy// go.mod

// Local development
replace github.com/myorg/shared => ../shared

// Fork with fixes
replace github.com/original/pkg => github.com/myorg/pkg-fork v1.2.3

// Exclude vulnerable version
exclude github.com/vulnerable/pkg v1.0.0

Workspace (Go 1.18+)

Copy// go.work
go 1.22

use (
    ./api
    ./shared
    ./worker
)

Copy# Initialize workspace
go work init ./api ./shared

# Add module to workspace
go work use ./worker

# Sync workspace
go work sync

Troubleshooting

Failure Modes

Debug Commands

Copygo mod graph                    # Show dependency graph
go mod why github.com/pkg/errors # Why is this needed?
go list -m -versions github.com/gin-gonic/gin # Available versions

Usage

CopySkill("go-modules")