Building a Go Dependency Scanner From Scratch

When managing Go projects, you need to track dependencies, check for vulnerabilities, and ensure license compliance. Instead of relying on external tools, let's build our own dependency analyzer using Go's standard library.

The Core Structure

We'll work with Go modules, so we need structures to represent them:

package main

import (
	"bufio"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"os"
	"regexp"
	"sort"
	"strings"
	"time"
)

type Module struct {
	Path     string
	Version  string
	Indirect bool
}

type GoMod struct {
	Module   Module
	Requires []Module
}

Our tool will handle three operations: listing dependencies, vulnerability scanning, and license checking.

Parsing go.mod Files

Understanding Module File Structure

The go.mod file uses a specific format that we need to parse correctly. Module declarations start with the module keyword followed by the module path. Dependencies are listed in require statements, which can be single-line or grouped in multi-line blocks.

The ...