Docker config and credential helper integration.

This crate provides functionality for resolving container registry credentials from Docker config files and credential helpers.

Overview

The main types in this crate are:

• [AuthResolver] - Resolves credentials for a registry
• [Credential] - A credential (anonymous, basic, bearer, etc.)
• [DockerConfig] - Parsed Docker config file

Example

use containerregistry_auth::{AuthResolver, Credential};

// Create a resolver that loads from default Docker config
let resolver = AuthResolver::new();

// Resolve credentials for a registry
let cred = resolver.resolve("gcr.io")?;

// Use the credential
if let Some(header) = cred.authorization_header() {
    println!("Authorization: {}", header);
}
# Ok::<(), containerregistry_auth::Error>(())

Resolution Order

The resolver checks multiple sources in order of precedence:

1. Explicit credentials (if set via [AuthResolver::with_explicit])
2. Docker config auths section (base64-encoded or plaintext)
3. Registry-specific credential helper (credHelpers)
4. Default credential store (credsStore)
5. Anonymous access (fallback)