blog: GitHub action environment variables

2024-10-12 16:50:13 +01:00 · 2024-10-12 16:50:13 +01:00 · 26ec9f891f
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+---
+title: >-
+  Setting environmental variables in a Step in a GitHub Action (with Supabase,
+  specifically)
+date: 2024-10-12T15:49:13.027Z
+slug: 2024-10-12-github-actions-environment-variables
+author: Thomas Wilson
+
+---
+Recently I thought "maybe it's about time my tests run in CI" for one of my side-projects ([herearethose.photos](https://herearethose.photos), a site for quickly and privately sharing photos).
+
+## The Problem 
+
+Using GitHub actions, it's possible to set job-level environment variables, and step-level environment variables.  But what if you need to set an environment variable *as the result of* a step in a job, and then reference them in a later step?
+
+## The Solution 
+
+Using a temporary file for a workflow, accessible at `GITHUB_ENV` (so `$GITHUB_ENV` in a script)
+
+[See GitHub's related documentation](https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/workflow-commands-for-github-actions#environment-files)
+
+## Why?
+
+I wanted my Supabase instance to be ephemeral: living only for the duration of the workflow then spun down.  Although some things are knowable before time (like URLs and ports), other things are generated on-the-flow (like authentication credentials).
+
+Storing these kinds of values as environmental variables is what allows the code to execute identically in local development, test, ci, production, and production-like (e.g. `staging`) environments.
+
+## The Code
+
+The following snippet assumes:
+
+- you're writing JavaScript or TypeScript
+- you're using pnpm for package management
+- you have a directory called `web` which has a `package.json` that has a script called `test:ci` - which runs your tests (mine calls `vitest`)
+- your code sources environment variables from the environment (`process.env.VARIABLE_NAME`), as opposed to from a known .env file (like `.env.ci`)
+
+```yaml
+name: Unit & Integration Tests
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    env:
+      PUBLIC_ENV_NAME: ci
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v3
+        with:
+          node-version: "20"
+
+      - name: Install pnpm
+        uses: pnpm/action-setup@v2
+        with:
+          version: 8
+
+      - name: Install dependencies
+        run: pnpm install
+
+      - name: Setup Supabase CLI
+        uses: supabase/setup-cli@v1
+        with:
+          version: latest
+
+      - name: Start Supabase and set environment variables
+        run: |
+          supabase start
+          supabase migration up --local
+          echo "PUBLIC_SUPABASE_URL=$(supabase status --output json | jq -r '.API_URL')" >> $GITHUB_ENV
+          echo "PUBLIC_SUPABASE_ANON_KEY=$(supabase status --output json | jq -r '.ANON_KEY')" >> $GITHUB_ENV
+          echo "SUPABASE_SERVICE_KEY=$(supabase status --output json | jq -r '.SERVICE_ROLE_KEY')" >> $GITHUB_ENV
+
+      - name: Run tests
+        env:
+          PUBLIC_SUPABASE_URL: ${{ env.PUBLIC_SUPABASE_URL }}
+          PUBLIC_SUPABASE_ANON_KEY: ${{ env.PUBLIC_SUPABASE_ANON_KEY }}
+          SUPABASE_SERVICE_KEY: ${{ env.SUPABASE_SERVICE_KEY }}
+        run: cd web && pnpm test:ci
+
+      - name: Stop Supabase
+        if: always()
+        run: supabase stop
+```