Build Docker workflow (gnmyt/Nexterm)
The Build Docker workflow from gnmyt/Nexterm, explained and optimized by Latchkey.
B
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Point runs-on at Latchkey and get job timeouts, SHA-pinned actions, self-healing for flaky steps, and up to 58% lower cost, applied automatically.
What it does
This is the Build Docker workflow from the gnmyt/Nexterm repository, a real project running GitHub Actions. It is shown here with attribution under its MIT license.
Below, Latchkey shows a faster, safer version produced by its optimization engine.
The workflow
workflow (.yml)
name: Build Docker
on:
workflow_call:
inputs:
version:
required: true
type: string
jobs:
build-components:
name: "Docker ${{ matrix.slug }} (${{ matrix.platform_arch }})"
runs-on: ${{ matrix.runner }}
strategy:
fail-fast: false
matrix:
slug: [server, engine]
platform_arch: [amd64, arm64]
include:
- platform_arch: amd64
platform: linux/amd64
runner: ubuntu-latest
- platform_arch: arm64
platform: linux/arm64
runner: ubuntu-24.04-arm
- slug: server
image_name: nexterm/server
dockerfile: Dockerfile.server
- slug: engine
image_name: nexterm/engine
dockerfile: Dockerfile.engine
steps:
- name: Checkout project
uses: actions/checkout@v4
with:
submodules: recursive
- name: Set up Docker Buildx
uses: docker/setup-buildx-action@v3
- name: Login to DockerHub
uses: docker/login-action@v3
with:
username: ${{ secrets.DOCKERHUB_USERNAME }}
password: ${{ secrets.DOCKERHUB_TOKEN }}
- name: Docker meta
id: meta
uses: docker/metadata-action@v5
with:
images: ${{ matrix.image_name }}
- name: Build and push by digest
id: build
uses: docker/build-push-action@v6
with:
context: .
file: ${{ matrix.dockerfile }}
platforms: ${{ matrix.platform }}
labels: ${{ steps.meta.outputs.labels }}
build-args: |
VERSION=${{ inputs.version }}
outputs: type=image,name=${{ matrix.image_name }},push-by-digest=true,name-canonical=true,push=true
cache-from: type=gha,scope=${{ matrix.slug }}-${{ matrix.platform_arch }}
cache-to: type=gha,mode=max,scope=${{ matrix.slug }}-${{ matrix.platform_arch }}
- name: Export digest
run: |
mkdir -p ${{ runner.temp }}/digests/${{ matrix.slug }}
digest="${{ steps.build.outputs.digest }}"
touch "${{ runner.temp }}/digests/${{ matrix.slug }}/${digest#sha256:}"
- name: Upload digest
uses: actions/upload-artifact@v4
with:
name: digests-${{ matrix.slug }}-${{ matrix.platform_arch }}
path: ${{ runner.temp }}/digests/${{ matrix.slug }}/
if-no-files-found: error
retention-days: 1
merge-components:
name: "Merge Manifests (${{ matrix.slug }})"
runs-on: ubuntu-latest
needs: build-components
strategy:
matrix:
include:
- image: nexterm/server
slug: server
- image: nexterm/engine
slug: engine
steps:
- name: Download digests
uses: actions/download-artifact@v4
with:
path: ${{ runner.temp }}/digests/${{ matrix.slug }}
pattern: digests-${{ matrix.slug }}-*
merge-multiple: true
- name: Set up Docker Buildx
uses: docker/setup-buildx-action@v3
- name: Login to DockerHub
uses: docker/login-action@v3
with:
username: ${{ secrets.DOCKERHUB_USERNAME }}
password: ${{ secrets.DOCKERHUB_TOKEN }}
- name: Create manifest list and push
run: |
docker buildx imagetools create \
-t ${{ matrix.image }}:latest \
-t ${{ matrix.image }}:${{ inputs.version }} \
$(printf '${{ matrix.image }}@sha256:%s ' $(ls "${{ runner.temp }}/digests/${{ matrix.slug }}"))
build-aio:
name: "Docker aio (${{ matrix.platform_arch }})"
runs-on: ${{ matrix.runner }}
needs: merge-components
strategy:
fail-fast: false
matrix:
platform_arch: [amd64, arm64]
include:
- platform_arch: amd64
platform: linux/amd64
runner: ubuntu-latest
- platform_arch: arm64
platform: linux/arm64
runner: ubuntu-24.04-arm
steps:
- name: Checkout project
uses: actions/checkout@v4
- name: Set up Docker Buildx
uses: docker/setup-buildx-action@v3
- name: Login to DockerHub
uses: docker/login-action@v3
with:
username: ${{ secrets.DOCKERHUB_USERNAME }}
password: ${{ secrets.DOCKERHUB_TOKEN }}
- name: Docker meta
id: meta
uses: docker/metadata-action@v5
with:
images: nexterm/aio
- name: Build and push by digest
id: build
uses: docker/build-push-action@v6
with:
context: .
file: Dockerfile
platforms: ${{ matrix.platform }}
labels: ${{ steps.meta.outputs.labels }}
build-args: |
SERVER_IMAGE=nexterm/server:${{ inputs.version }}
ENGINE_IMAGE=nexterm/engine:${{ inputs.version }}
outputs: type=image,name=nexterm/aio,push-by-digest=true,name-canonical=true,push=true
cache-from: type=gha,scope=aio-${{ matrix.platform_arch }}
cache-to: type=gha,mode=max,scope=aio-${{ matrix.platform_arch }}
- name: Export digest
run: |
mkdir -p ${{ runner.temp }}/digests/aio
digest="${{ steps.build.outputs.digest }}"
touch "${{ runner.temp }}/digests/aio/${digest#sha256:}"
- name: Upload digest
uses: actions/upload-artifact@v4
with:
name: digests-aio-${{ matrix.platform_arch }}
path: ${{ runner.temp }}/digests/aio/
if-no-files-found: error
retention-days: 1
merge-aio:
name: "Merge Manifests (aio)"
runs-on: ubuntu-latest
needs: build-aio
steps:
- name: Download digests
uses: actions/download-artifact@v4
with:
path: ${{ runner.temp }}/digests/aio
pattern: digests-aio-*
merge-multiple: true
- name: Set up Docker Buildx
uses: docker/setup-buildx-action@v3
- name: Login to DockerHub
uses: docker/login-action@v3
with:
username: ${{ secrets.DOCKERHUB_USERNAME }}
password: ${{ secrets.DOCKERHUB_TOKEN }}
- name: Create manifest list and push
run: |
docker buildx imagetools create \
-t nexterm/aio:latest \
-t nexterm/aio:${{ inputs.version }} \
$(printf 'nexterm/aio@sha256:%s ' $(ls "${{ runner.temp }}/digests/aio"))
The same workflow, on Latchkey
Removes redundant runs and caps runaway jobs. Added and changed lines are highlighted.
name: Build Docker on: workflow_call: inputs: version: required: true type: string jobs: build-components: timeout-minutes: 30 name: "Docker ${{ matrix.slug }} (${{ matrix.platform_arch }})" runs-on: ${{ matrix.runner }} strategy: fail-fast: false matrix: slug: [server, engine] platform_arch: [amd64, arm64] include: - platform_arch: amd64 platform: linux/amd64 runner: ubuntu-latest - platform_arch: arm64 platform: linux/arm64 runner: ubuntu-24.04-arm - slug: server image_name: nexterm/server dockerfile: Dockerfile.server - slug: engine image_name: nexterm/engine dockerfile: Dockerfile.engine steps: - name: Checkout project uses: actions/checkout@v4 with: submodules: recursive - name: Set up Docker Buildx uses: docker/setup-buildx-action@v3 - name: Login to DockerHub uses: docker/login-action@v3 with: username: ${{ secrets.DOCKERHUB_USERNAME }} password: ${{ secrets.DOCKERHUB_TOKEN }} - name: Docker meta id: meta uses: docker/metadata-action@v5 with: images: ${{ matrix.image_name }} - name: Build and push by digest id: build uses: docker/build-push-action@v6 with: context: . file: ${{ matrix.dockerfile }} platforms: ${{ matrix.platform }} labels: ${{ steps.meta.outputs.labels }} build-args: | VERSION=${{ inputs.version }} outputs: type=image,name=${{ matrix.image_name }},push-by-digest=true,name-canonical=true,push=true cache-from: type=gha,scope=${{ matrix.slug }}-${{ matrix.platform_arch }} cache-to: type=gha,mode=max,scope=${{ matrix.slug }}-${{ matrix.platform_arch }} - name: Export digest run: | mkdir -p ${{ runner.temp }}/digests/${{ matrix.slug }} digest="${{ steps.build.outputs.digest }}" touch "${{ runner.temp }}/digests/${{ matrix.slug }}/${digest#sha256:}" - name: Upload digest uses: actions/upload-artifact@v4 with: name: digests-${{ matrix.slug }}-${{ matrix.platform_arch }} path: ${{ runner.temp }}/digests/${{ matrix.slug }}/ if-no-files-found: error retention-days: 1 merge-components: timeout-minutes: 30 name: "Merge Manifests (${{ matrix.slug }})" runs-on: latchkey-small needs: build-components strategy: matrix: include: - image: nexterm/server slug: server - image: nexterm/engine slug: engine steps: - name: Download digests uses: actions/download-artifact@v4 with: path: ${{ runner.temp }}/digests/${{ matrix.slug }} pattern: digests-${{ matrix.slug }}-* merge-multiple: true - name: Set up Docker Buildx uses: docker/setup-buildx-action@v3 - name: Login to DockerHub uses: docker/login-action@v3 with: username: ${{ secrets.DOCKERHUB_USERNAME }} password: ${{ secrets.DOCKERHUB_TOKEN }} - name: Create manifest list and push run: | docker buildx imagetools create \ -t ${{ matrix.image }}:latest \ -t ${{ matrix.image }}:${{ inputs.version }} \ $(printf '${{ matrix.image }}@sha256:%s ' $(ls "${{ runner.temp }}/digests/${{ matrix.slug }}")) build-aio: timeout-minutes: 30 name: "Docker aio (${{ matrix.platform_arch }})" runs-on: ${{ matrix.runner }} needs: merge-components strategy: fail-fast: false matrix: platform_arch: [amd64, arm64] include: - platform_arch: amd64 platform: linux/amd64 runner: ubuntu-latest - platform_arch: arm64 platform: linux/arm64 runner: ubuntu-24.04-arm steps: - name: Checkout project uses: actions/checkout@v4 - name: Set up Docker Buildx uses: docker/setup-buildx-action@v3 - name: Login to DockerHub uses: docker/login-action@v3 with: username: ${{ secrets.DOCKERHUB_USERNAME }} password: ${{ secrets.DOCKERHUB_TOKEN }} - name: Docker meta id: meta uses: docker/metadata-action@v5 with: images: nexterm/aio - name: Build and push by digest id: build uses: docker/build-push-action@v6 with: context: . file: Dockerfile platforms: ${{ matrix.platform }} labels: ${{ steps.meta.outputs.labels }} build-args: | SERVER_IMAGE=nexterm/server:${{ inputs.version }} ENGINE_IMAGE=nexterm/engine:${{ inputs.version }} outputs: type=image,name=nexterm/aio,push-by-digest=true,name-canonical=true,push=true cache-from: type=gha,scope=aio-${{ matrix.platform_arch }} cache-to: type=gha,mode=max,scope=aio-${{ matrix.platform_arch }} - name: Export digest run: | mkdir -p ${{ runner.temp }}/digests/aio digest="${{ steps.build.outputs.digest }}" touch "${{ runner.temp }}/digests/aio/${digest#sha256:}" - name: Upload digest uses: actions/upload-artifact@v4 with: name: digests-aio-${{ matrix.platform_arch }} path: ${{ runner.temp }}/digests/aio/ if-no-files-found: error retention-days: 1 merge-aio: timeout-minutes: 30 name: "Merge Manifests (aio)" runs-on: latchkey-small needs: build-aio steps: - name: Download digests uses: actions/download-artifact@v4 with: path: ${{ runner.temp }}/digests/aio pattern: digests-aio-* merge-multiple: true - name: Set up Docker Buildx uses: docker/setup-buildx-action@v3 - name: Login to DockerHub uses: docker/login-action@v3 with: username: ${{ secrets.DOCKERHUB_USERNAME }} password: ${{ secrets.DOCKERHUB_TOKEN }} - name: Create manifest list and push run: | docker buildx imagetools create \ -t nexterm/aio:latest \ -t nexterm/aio:${{ inputs.version }} \ $(printf 'nexterm/aio@sha256:%s ' $(ls "${{ runner.temp }}/digests/aio"))
What changed
- Run on Latchkey managed runners with one line (
runs-on), which apply the fixes below automatically and self-heal transient failures. This example useslatchkey-small; pick the runner size that fits the job. - Add a job timeout so a hung step cannot burn hours of runner time.
4 third-party actions are referenced by a movable tag. Pin them to the commit SHA (Latchkey resolves and applies this automatically) so a repointed tag cannot change what runs.
What Latchkey heals here
This workflow has steps that commonly fail on transient issues (network, registries, flaky browsers). On Latchkey managed runners they are detected, retried, and self-healed instead of failing your build:
- Container pulls and builds
This workflow runs 4 jobs (8 with the matrix expanded) per trigger. On Latchkey the same minutes cost up to 58% less than GitHub-hosted, with zero queue time.