version

Package version

Purpose

Provides container image version checking by querying OCI registries for available tags and comparing them to current versions.

Functionality

• Registry tag listing - Fetch all available tags for an image from any OCI registry
• Semantic version parsing - Extract and compare semantic versions (e.g., 1.2.3, 2.10.2)
• Variant support - Handle image variants (e.g., alpine, distroless-static)
• Update detection - Determine if newer versions are available
• Digest retrieval - Get digest for specific version tags
• Auto-variant extraction - Automatically extract variant suffix from version strings

Public API

type Checker struct { ... }
func NewChecker(username, password string, log zerolog.Logger) *Checker

// Version checking
func (c *Checker) CheckVersion(imageRef, currentVersion, variant string) (*Info, error)
func (c *Checker) GetTagDigest(imageRef string) (string, error)

// Result type
type Info struct {
    CurrentVersion  string
    LatestVersion   string
    LatestDigest    string
    UpdateAvailable bool
}

Design

• Registry-agnostic: Works with any OCI-compliant registry (Docker Hub, GHCR, etc.)
• Semantic versioning: Parses and compares versions using custom semver logic
• Variant filtering: Only compares versions with matching variant suffixes
• Tag enumeration: Lists all tags and filters to valid semantic versions
• Digest retrieval: Fetches digest for specific version tags (immutable references)

Version Format Support

Supports various version formats:

• Simple semver: 1.2.3, 2.10.2
• Variant suffixes: 2.10.2-alpine, 1.0.0-distroless-static
• Leading 'v': v1.2.3 (automatically stripped)

Variant Extraction

Variant is the part after the version number:

• 2.10.2-distroless-static → version: 2.10.2, variant: distroless-static
• 1.2.3-alpine → version: 1.2.3, variant: alpine
• 1.0.0 → version: 1.0.0, variant: empty

Version Comparison

Uses component-wise comparison:

• 1.2.3 < 1.2.4 (patch increment)
• 1.2.3 < 1.3.0 (minor increment)
• 1.9.9 < 2.0.0 (major increment)
• 1.10.0 > 1.9.0 (numeric comparison, not string)

Dependencies

• External: google/go-containerregistry for OCI registry operations
• Internal: None (standalone module)

Security Notes

• Supports authenticated registry access (username/password)
• Retrieves digests for immutable image references
• Tag-based version checking is informational only (tags can be moved)