1---
2title: Use GitHub Actions
3description: Learn how to use GitHub Actions to automate publishing updates with EAS Update.
4---
5
6import { Step } from '~/ui/components/Step';
7
8A GitHub Action is a cloud function that runs every time an event on GitHub occurs. We can use GitHub Actions to automate building and publishing updates when you or members of your team merge to a branch, like "production". This makes the process of deploying consistent and fast, leaving you more time to develop your app.
9
10## Publish updates on push
11
12We can configure GitHub Actions to run on any GitHub event. One of the most common use cases is to publish an update when code is pushed. Below are the steps to publish an update every time an update is pushed:
13
14<Step label="1">
15
16Create a file path named **.github/workflows/update.yml** at the root of your project.
17
18</Step>
19
20<Step label="2">
21
22Inside **update.yml**, copy and paste the following snippet:
23
24```yaml update.yml
25name: update
26on: push
27
28jobs:
29  update:
30    name: EAS Update
31    runs-on: ubuntu-latest
32    steps:
33      - name: Check for EXPO_TOKEN
34        run: |
35          if [ -z "${{ secrets.EXPO_TOKEN }}" ]; then
36            echo "You must provide an EXPO_TOKEN secret linked to this project's Expo account in this repo's secrets. Learn more: https://docs.expo.dev/eas-update/github-actions"
37            exit 1
38          fi
39
40      - name: Checkout repository
41        uses: actions/checkout@v3
42
43      - name: Setup Node
44        uses: actions/setup-node@v3
45        with:
46          node-version: 18.x
47          cache: yarn
48
49      - name: Setup EAS
50        uses: expo/expo-github-action@v8
51        with:
52          eas-version: latest
53          token: ${{ secrets.EXPO_TOKEN }}
54
55      - name: Install dependencies
56        run: yarn install
57
58      - name: Publish update
59        run: eas update --auto
60```
61
62In the code above, we set the action to run every time code is pushed to any branch. In the `update` job, we set up Node, in addition to Expo's GitHub Action: `expo-github-action`. We then add a couple of steps to cache any dependencies installed from the last run to speed this script up on subsequent runs. In the end, we install dependencies (`yarn install`), then publish the update with `eas update --auto`. Since we're using the `--auto` flag, the EAS branch will be named after the GitHub branch, and the message for the update will match the commit's message.
63
64</Step>
65
66<Step label="3">
67
68Finally, we need to give the script above permission to run by providing an `EXPO_TOKEN` environment variable.
69
701.  Navigate to [https://expo.dev/settings/access-tokens](https://expo.dev/settings/access-tokens).
712.  Click "Create" to create a new access token.
723.  Copy the token generated.
734.  Navigate to https://github.com/your-username/your-repo-name/settings/secrets/actions, replacing "your-username" and "your-repo-name" with your project's info.
745.  Click "New repository secret"
756.  Make the secret's name "EXPO_TOKEN", then paste the access token in as the value.
76
77Your GitHub Action should be set up now. Whenever a developer merges code into the repo, this action will build an update and publish it, making it available to all of our devices with builds that have access to the EAS branch.
78
79> Some repositories or organizations might need to explicitly enable GitHub Workflows and allow third-party Actions.
80
81</Step>
82
83## Publish previews on pull requests
84
85Another common use case it to create a new update for every pull request. This allows you to test the changes in the pull request on a device before merging the code, and without having to start the project locally. Below are the steps to publish an update every time a pull request is opened:
86
87<Step label="1">
88
89Create a file path named **.github/workflows/preview.yml** at the root of your project.
90
91</Step>
92
93<Step label="2">
94
95Inside **preview.yml**, copy and paste the following snippet:
96
97```yaml preview.yml
98name: preview
99on: pull_request
100
101jobs:
102  update:
103    name: EAS Update
104    runs-on: ubuntu-latest
105    permissions:
106      pull-requests: write
107    steps:
108      - name: Check for EXPO_TOKEN
109        run: |
110          if [ -z "${{ secrets.EXPO_TOKEN }}" ]; then
111            echo "You must provide an EXPO_TOKEN secret linked to this project's Expo account in this repo's secrets. Learn more: https://docs.expo.dev/eas-update/github-actions"
112            exit 1
113          fi
114
115      - name: Checkout repository
116        uses: actions/checkout@v3
117
118      - name: Setup Node
119        uses: actions/setup-node@v3
120        with:
121          node-version: 18.x
122          cache: yarn
123
124      - name: Setup EAS
125        uses: expo/expo-github-action@v8
126        with:
127          eas-version: latest
128          token: ${{ secrets.EXPO_TOKEN }}
129
130      - name: Install dependencies
131        run: yarn install
132
133      - name: Create preview
134        uses: expo/expo-github-action/preview@v8
135        with:
136          command: eas update --auto
137```
138
139Although the code above is similar to the example in the previous section, there are a few differences. In this action, we changed the workflow event (`on`) to run every time a pull request is opened or updated. In the `update` job, we still set up Node, Expo's GitHub Action, and the dependencies using GitHub action's built-in cache. But, instead of running `eas update --auto` ourselves, we let the [preview subaction](https://github.com/expo/expo-github-action/tree/main/preview#readme) run it for us. This will add a comment to the pull request with basic information about the update and a QR code to scan the update.
140
141> Don't forget to add the `permissions` section to the job. This enables the job to add comments to the pull request.
142
143</Step>
144
145<Step label="3">
146
147
148You can skip this step if you have already set up `EXPO_TOKEN` in the previous section. Only one valid `EXPO_TOKEN` is required to authenticate GitHub Actions with your Expo account.
149
150If you haven't, you must give the script above permission to run by providing an `EXPO_TOKEN` environment variable.
151
1521.  Navigate to [https://expo.dev/settings/access-tokens](https://expo.dev/settings/access-tokens).
1532.  Click "Create" to create a new access token.
1543.  Copy the token generated.
1554.  Navigate to https://github.com/your-username/your-repo-name/settings/secrets/actions, replacing "your-username" and "your-repo-name" with your project's info.
1565.  Click "New repository secret"
1576.  Make the secret's name "EXPO_TOKEN", then paste the access token in as the value.
158
159Your GitHub Action should be set up now. Whenever a developer creates a pull request, this action will build an update and publish it, making it available to all reviewers with builds that have access to the EAS branch.
160
161> Some repositories or organizations might need to explicitly enable GitHub Workflows and allow third-party Actions.
162
163</Step>
164