resolve-hexpm-image

Resolves the latest hexpm/elixir Docker image tag for given Elixir/OTP versions and OS distribution.

Handles version prefix resolution (e.g., 1.17 → 1.17.3), base image date tag discovery, and hexpm tag verification — all via stdlib-only Python 3.

Usage

- uses: qdentity/resolve-hexpm-image@v1
  id: images
  with:
    elixir-version: '1.17'
    otp-version: '27'

- run: docker pull ${{ steps.images.outputs.builder-image }}

Inputs

Input	Required	Default	Description
elixir-version	yes	—	Elixir version prefix (1.17 → latest 1.17.x)
otp-version	yes	—	OTP version prefix (28 → latest 28.x.y)
distribution	no	bookworm	OS codename or alpine
os-family	no	auto	debian, ubuntu, alpine, or auto
variant	no	auto	auto = slim for debian, none for ubuntu/alpine
max-candidates	no	5	Base image date tags to try
github-token	no	${{ github.token }}	GitHub API token

Outputs

Output	Example
builder-image	hexpm/elixir:1.17.3-erlang-27.1.2-debian-bookworm-20260316-slim
runner-image	debian:bookworm-20260316-slim
elixir-version	1.17.3
otp-version	27.1.2
builder-digest	sha256:...

Examples

# Ubuntu noble:
- uses: qdentity/resolve-hexpm-image@v1
  with:
    elixir-version: '1.18.4'
    otp-version: '28.0.2'
    distribution: noble

# Alpine:
- uses: qdentity/resolve-hexpm-image@v1
  with:
    elixir-version: '1.16.3'
    otp-version: '26.2.5'
    distribution: alpine

# Explicit OS family:
- uses: qdentity/resolve-hexpm-image@v1
  with:
    elixir-version: '1.19'
    otp-version: '28.3'
    distribution: trixie
    os-family: debian