version_resolver

Documentation

Overview

Package version_resolver maps a runtime name and user-supplied version string to a Docker image reference.

Version inputs are intentionally loose — a major ("3"), a minor ("3.12"), or a full patch pin ("3.12.7") are all valid. Missing precision is filled in by querying endoflife.date, which picks the latest non-EOL release that matches the prefix.

Responses are cached per product for 24 hours. A failed refresh serves the previous data so a transient outage to endoflife.date does not block builds.

Runtimes with multi-stage Dockerfiles (nodejs, java) expose separate builder and runner images through Resolution. Single-stage runtimes return the same image for both.

Two inputs are always rejected: strings that do not parse as a version prefix (letters, extra dots, wildcards), and versions whose end-of-life date has already passed.

Index

• type Cycle
• type EOLClient
  • func NewHTTPClient() EOLClient
• type EOLDate
  • func NewEOLDate(date string) EOLDate
  • func (e EOLDate) Expired() bool
  • func (e EOLDate) String() string
  • func (e *EOLDate) UnmarshalJSON(b []byte) error
• type FlexBool
  • func NewFlexBool(v bool) FlexBool
  • func (f FlexBool) Bool() bool
  • func (f *FlexBool) UnmarshalJSON(b []byte) error
• type Resolution
• type Resolver
  • func New(client EOLClient) *Resolver
  • func (r *Resolver) Resolve(runtime, version string) (Resolution, error)

Types

type Cycle

type Cycle struct {
	Cycle       string   `json:"cycle"`
	Latest      string   `json:"latest"`
	EOL         EOLDate  `json:"eol"`
	ReleaseDate string   `json:"releaseDate"`
	LTS         FlexBool `json:"lts"`
}

Cycle is a single release line as returned by endoflife.date.

type EOLClient

type EOLClient interface {
	Cycles(product string) ([]Cycle, error)
}

EOLClient fetches release cycle data for a given product. The product name matches endoflife.date's URL slug (e.g. "python", "nodejs").

func NewHTTPClient

func NewHTTPClient() EOLClient

NewHTTPClient returns an EOLClient backed by endoflife.date with a 24-hour cache.

type EOLDate

type EOLDate struct {
	// contains filtered or unexported fields
}

EOLDate is either "no end-of-life" (the zero value) or a calendar date. The endoflife.date API encodes this as either the boolean false or a "YYYY-MM-DD" string, so a custom unmarshaler is required.

func NewEOLDate

func NewEOLDate(date string) EOLDate

NewEOLDate constructs an EOLDate from a "YYYY-MM-DD" string. Pass "" to represent a release with no scheduled end-of-life.

func (EOLDate) Expired

func (e EOLDate) Expired() bool

Expired reports whether the end-of-life date has already passed.

func (EOLDate) String

func (e EOLDate) String() string

func (*EOLDate) UnmarshalJSON

func (e *EOLDate) UnmarshalJSON(b []byte) error

type FlexBool

type FlexBool struct {
	// contains filtered or unexported fields
}

FlexBool unmarshals a JSON value that is either a boolean or a date string (e.g. Node.js LTS end dates). Any truthy value is treated as true.

func NewFlexBool

func NewFlexBool(v bool) FlexBool

func (FlexBool) Bool

func (f FlexBool) Bool() bool

func (*FlexBool) UnmarshalJSON

func (f *FlexBool) UnmarshalJSON(b []byte) error

type Resolution

type Resolution struct {
	// BuilderImage is the primary FROM image (used for single-stage builds and
	// the first stage of multi-stage builds).
	BuilderImage string
	// RunnerImage is the lightweight runtime image used in the final stage of
	// multi-stage builds. It equals BuilderImage for single-stage runtimes.
	RunnerImage string
	// Version is the resolved version tag (e.g. "3.12", "21") without the
	// image name, useful when constructing secondary images inside a Dockerfile.
	Version string
	// Warning is non-empty when the resolved version is end-of-life.
	Warning string
}

Resolution holds the images produced for a single resolve call.

type Resolver

type Resolver struct {
	// contains filtered or unexported fields
}

Resolver resolves user-supplied runtime versions to concrete Docker image references using live release-cycle data from endoflife.date.

func New

func New(client EOLClient) *Resolver

New returns a Resolver backed by the given EOLClient.

func (*Resolver) Resolve

func (r *Resolver) Resolve(runtime, version string) (Resolution, error)

Resolve returns the Docker images for the given runtime and version string.

An empty version picks the latest stable release. A partial version (major or major.minor) is resolved to the most recent non-EOL cycle in that line. A full patch version is validated against the known cycle data and passed through, subject to the runtime's maximum tag granularity.