Add build branch workflow

Author: lewazo

.github/workflows/build_branch.yml

@@ -0,0 +1,75 @@
+name: Build branch for docker
+
+on:
+  workflow_dispatch:
+    inputs:
+      branch:
+        description: "Branch to build"
+        required: true
+
+env:
+  AWS_REGION: us-west-1
+  AWS_ROLE: ${{ vars.EC2_GITHUB_RUNNER_ROLE }}
+  REGISTRY_IMAGE: oxen/oxen-server
+
+permissions:
+  id-token: write
+  contents: write
+
+jobs:
+  start-self-hosted-runner:
+    name: Start self-hosted EC2 runner
+    runs-on: ubuntu-latest
+    outputs:
+      label: ${{ steps.start-ec2-runner.outputs.label }}
+      ec2-instance-id: ${{ steps.start-ec2-runner.outputs.ec2-instance-id }}
+
+    steps:
+      - name: Configure AWS credentials
+        uses: aws-actions/configure-aws-credentials@v4
+        with:
+          role-to-assume: ${{ env.AWS_ROLE }}
+          role-duration-seconds: 900
+          aws-region: ${{ env.AWS_REGION }}
+
+      - name: Start EC2 runner
+        id: start-ec2-runner
+        uses: machulav/ec2-github-runner@v2
+        with:
+          mode: start
+          github-token: ${{ secrets.GH_PERSONAL_ACCESS_TOKEN }}
+          ec2-image-id: ${{ vars.EC2_IMAGE_ID }}
+          ec2-instance-type: m7g.4xlarge
+          subnet-id: ${{ vars.SUBNET_ID }}
+          security-group-id: ${{ vars.SECURITY_GROUP_ID }}
+          aws-resource-tags: >
+            [
+              {"Key": "Name", "Value": "ec2-github-runner"}
+            ]
+
+  release_docker_arm64:
+    needs: start-self-hosted-runner
+    runs-on: ${{ needs.start-self-hosted-runner.outputs.label }}
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.inputs.branch }}
+
+      - name: Set release version
+        run: |
+          echo "RELEASE_VERSION=nighly-$(date +'%Y-%m-%d-%H_%M_%S')" >> $GITHUB_ENV
+
+      - name: Build Docker Image
+        run: docker build -t oxen/oxen-server .
+
+      - name: Save Docker
+        run: docker save oxen/oxen-server -o oxen-server-docker-arm64-${{ env.RELEASE_VERSION }}.tar
+
+      - name: Upload Artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: oxen-server-docker-arm64-${{ env.RELEASE_VERSION }}.tar
+          path: oxen-server-docker-arm64-${{ env.RELEASE_VERSION }}.tar
+          retention-days: 1