# GitHub

By default, new Coder deployments use a Coder-managed GitHub app to authenticate
users.
We provide it for convenience, allowing you to experiment with Coder
without setting up your own GitHub OAuth app.

If you authenticate with it, you grant Coder server read access to your GitHub
user email and other metadata listed during the authentication flow.

This access is necessary for the Coder server to complete the authentication
process.
To the best of our knowledge, Coder, the company, does not gain access
to this data by administering the GitHub app.

## Default Configuration

<Callout type="idea" title="Important">
  Installation of the default GitHub app grants Coder (the company) access to your organization's GitHub data.

  For production environments, we strongly recommend that you
  [configure your own GitHub OAuth app](#step-1-configure-the-oauth-application-in-github)
  to ensure that your data is not shared with Coder (the company).
</Callout>

To use the default configuration:

1. [Install the GitHub app](https://github.com/apps/coder/installations/select_target)
   in any GitHub organization that you want to use with Coder.

   The default GitHub app requires [device flow](#device-flow) to authenticate.
   This is enabled by default when using the default GitHub app.
   If you disable device flow using `CODER_OAUTH2_GITHUB_DEVICE_FLOW=false`, it will be ignored.

2. By default, only the admin user can sign up.
   To allow additional users to sign up with GitHub, add:

   ```shell
   CODER_OAUTH2_GITHUB_ALLOW_SIGNUPS=true
   ```

3. (Optional) If you want to limit sign-ups to specific GitHub organizations, set:

   ```shell
   CODER_OAUTH2_GITHUB_ALLOWED_ORGS="your-org"
   ```

## Disable the Default GitHub App

You can disable the default GitHub app by [configuring your own app](#step-1-configure-the-oauth-application-in-github)
or by adding the following environment variable to your [Coder server configuration](/docs/@v2.33.6/reference/cli/server/#options):

```shell
CODER_OAUTH2_GITHUB_DEFAULT_PROVIDER_ENABLE=false
```

<Callout type="info" title="Note">
  After you disable the default GitHub provider, the **Sign in with GitHub** button
  might still appear on your login page even though the authentication flow is disabled.

  To completely hide the GitHub sign-in button, you must disable the default provider
  and ensure you don't have a custom GitHub OAuth app configured.
</Callout>

<div className="fd-steps">
  <div className="fd-step">
    ## Configure the OAuth application in GitHub

    1. [Register a GitHub OAuth app](https://developer.github.com/apps/building-oauth-apps/creating-an-oauth-app/).

    2. GitHub will ask you for the following Coder parameters:

       * **Homepage URL**: Set to your Coder deployment's
         [`CODER_ACCESS_URL`](/docs/@v2.33.6/reference/cli/server/#--access-url) (e.g.
         `https://coder.domain.com`)
       * **User Authorization Callback URL**: Set to `https://coder.domain.com`

         If you want to allow multiple Coder deployments hosted on subdomains, such as
         `coder1.domain.com`, `coder2.domain.com`, to authenticate with the
         same GitHub OAuth app, then you can set **User Authorization Callback URL** to
         the `https://domain.com`

    3. Take note of the Client ID and Client Secret generated by GitHub.
       You will use these values in the next step.

    4. Coder needs permission to access user email addresses.

       Find the **Account Permissions** settings for your app and select **read-only** for **Email addresses**.
  </div>

  <div className="fd-step">
    ## Configure Coder with the OAuth credentials

    Go to your Coder host and run the following command to start up the Coder server:

    ```shell
    coder server --oauth2-github-allow-signups=true --oauth2-github-allowed-orgs="your-org" --oauth2-github-client-id="8d1...e05" --oauth2-github-client-secret="57ebc9...02c24c"
    ```

    <Callout type="info" title="Note">
      For GitHub Enterprise support, specify the `--oauth2-github-enterprise-base-url` flag.
    </Callout>

    Alternatively, if you are running Coder as a system service, you can achieve the
    same result as the command above by adding the following environment variables
    to the `/etc/coder.d/coder.env` file:

    ```shell
    CODER_OAUTH2_GITHUB_ALLOW_SIGNUPS=true
    CODER_OAUTH2_GITHUB_ALLOWED_ORGS="your-org"
    CODER_OAUTH2_GITHUB_CLIENT_ID="8d1...e05"
    CODER_OAUTH2_GITHUB_CLIENT_SECRET="57ebc9...02c24c"
    ```

    <Callout type="success" title="Tip">
      To allow everyone to sign up using GitHub, set:

      ```shell
      CODER_OAUTH2_GITHUB_ALLOW_EVERYONE=true
      ```
    </Callout>

    Once complete, run `sudo service coder restart` to reboot Coder.

    If deploying Coder via Helm, you can set the above environment variables in the
    `values.yaml` file as such:

    ```yaml
    coder:
      env:
        - name: CODER_OAUTH2_GITHUB_ALLOW_SIGNUPS
          value: "true"
        - name: CODER_OAUTH2_GITHUB_CLIENT_ID
          value: "533...des"
        - name: CODER_OAUTH2_GITHUB_CLIENT_SECRET
          value: "G0CSP...7qSM"
        # If setting allowed orgs, comment out CODER_OAUTH2_GITHUB_ALLOW_EVERYONE and its value
        - name: CODER_OAUTH2_GITHUB_ALLOWED_ORGS
          value: "your-org"
        # If allowing everyone, comment out CODER_OAUTH2_GITHUB_ALLOWED_ORGS and it's value
        #- name: CODER_OAUTH2_GITHUB_ALLOW_EVERYONE
        #  value: "true"
    ```

    To upgrade Coder, run:

    ```shell
    helm upgrade <release-name> coder-v2/coder -n <namespace> -f values.yaml
    ```

    We recommend requiring and auditing MFA usage for all users in your GitHub organizations.
    This can be enforced from the organization settings page in the **Authentication security** sidebar tab.
  </div>
</div>

## Device Flow

Coder supports
[device flow](https://docs.github.com/en/apps/oauth-apps/building-oauth-apps/authorizing-oauth-apps#device-flow)
for GitHub OAuth.
This is enabled by default for the default GitHub app and cannot be disabled for that app.

For your own custom GitHub OAuth app, you can enable device flow by setting:

```shell
CODER_OAUTH2_GITHUB_DEVICE_FLOW=true
```

Device flow is optional for custom GitHub OAuth apps.
We generally recommend using the standard OAuth flow instead, as it is more convenient for end users.

<Callout type="info" title="Note">
  If you're using the default GitHub app, device flow is always enabled regardless of
  the `CODER_OAUTH2_GITHUB_DEVICE_FLOW` setting.
</Callout>