# GitHub

## Default Configuration

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. Once you authenticate with it, you
grant Coder server read access to:

- Your GitHub user email
- Your GitHub organization membership
- 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.

> [!IMPORTANT]
> 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.

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

```env
CODER_OAUTH2_GITHUB_ALLOW_SIGNUPS=true
```

To limit sign ups to members of specific GitHub organizations, set:

```env
CODER_OAUTH2_GITHUB_ALLOWED_ORGS="your-org"
```

For production deployments, we recommend configuring your own GitHub OAuth app
as outlined below. The default is automatically disabled if you configure your
own app or set:

```env
CODER_OAUTH2_GITHUB_DEFAULT_PROVIDER_ENABLE=false
```

> [!NOTE]
> After you disable the default GitHub provider with the setting above, 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 both disable the default
> provider and ensure you don't have a custom GitHub OAuth app configured.

## Step 1: Configure the OAuth application in GitHub

First,
[register a GitHub OAuth app](https://developer.github.com/apps/building-oauth-apps/creating-an-oauth-app/).
GitHub will ask you for the following Coder parameters:

- **Homepage URL**: Set to your Coder deployments
  [`CODER_ACCESS_URL`](../../reference/cli/server.md#--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`

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

Coder will need permission to access user email addresses. Find the "Account
Permissions" settings for your app and select "read-only" for "Email addresses".

## Step 2: Configure Coder with the OAuth credentials

Navigate 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"
```

> [!NOTE]
> For GitHub Enterprise support, specify the `--oauth2-github-enterprise-base-url` flag.

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:

```env
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"
```

> [!TIP]
> To allow everyone to sign up using GitHub, set:
>
> ```env
> CODER_OAUTH2_GITHUB_ALLOW_EVERYONE=true
> ```

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.

## 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:

```env
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.

> [!NOTE]
> If you're using the default GitHub app, device flow is always enabled regardless of
> the `CODER_OAUTH2_GITHUB_DEVICE_FLOW` setting.