Docker Image Digest (SHA256) Regex for Go

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching docker image digest (sha256), ported and verified for Go. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Go project — whether you're validating in a Gin handler, a gRPC service, or a command-line tool.

Go Implementation

// Docker Image Digest (SHA256)
// ReDoS-safe | RegexVault — Dev & Systems > Docker

package validation

import "regexp"

var dockerImageDigestSha256Re = regexp.MustCompile(`^sha256:[a-fA-F0-9]{64}$`)

func ValidateDockerImageDigestSha256(s string) bool {
    return dockerImageDigestSha256Re.MatchString(s)
}

// Example
// fmt.Println(ValidateDockerImageDigestSha256("sha256:a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Dev & Systems > Docker category and carries a ReDoS-safe certification. That matters for Go developers because Go's RE2 engine is inherently safe from catastrophic backtracking, but this pattern has been additionally verified for correctness. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

64 hex characters = 256 bits = SHA-256 output. The sha256: prefix is mandatory for algorithm agility. Digest pinning provides immutable image references.