From 88622e642252008d10b8769f7182875412b80239 Mon Sep 17 00:00:00 2001
From: Nicolas Arnold <nic@roadie.io>
Date: Mon, 27 Sep 2021 10:40:44 +0100
Subject: [PATCH] Add ability to override github app callback url

By default, the github app provider redirects back to the base url.
This change allows a user to override the GitHub App url using the config field `customCallbackUrl`.

It will look like this in the configuration:
```
auth:
  providers:
    github:
      development:
        clientId: SUPER ID
        clientSecret: SUPER SECRET
        customCallbackUrl: https://some-url.com/callback
```

Signed-off-by: Nicolas Arnold <nic@roadie.io>
---
 .changeset/pretty-feet-explode.md                     | 5 +++++
 plugins/auth-backend/src/providers/github/provider.ts | 6 +++++-
 2 files changed, 10 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/pretty-feet-explode.md

diff --git a/.changeset/pretty-feet-explode.md b/.changeset/pretty-feet-explode.md
new file mode 100644
index 0000000000..c5cf0beb00
--- /dev/null
+++ b/.changeset/pretty-feet-explode.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-auth-backend': patch
+---
+
+Allow users to override callback url of Github provider
diff --git a/plugins/auth-backend/src/providers/github/provider.ts b/plugins/auth-backend/src/providers/github/provider.ts
index b6b198b644..8abd4c76ea 100644
--- a/plugins/auth-backend/src/providers/github/provider.ts
+++ b/plugins/auth-backend/src/providers/github/provider.ts
@@ -223,6 +223,9 @@ export const createGithubProvider = (
       const enterpriseInstanceUrl = envConfig.getOptionalString(
         'enterpriseInstanceUrl',
       );
+      const customCallbackUrl = envConfig.getOptionalString(
+        'customCallbackUrl',
+      );
       const authorizationUrl = enterpriseInstanceUrl
         ? `${enterpriseInstanceUrl}/login/oauth/authorize`
         : undefined;
@@ -232,7 +235,8 @@ export const createGithubProvider = (
       const userProfileUrl = enterpriseInstanceUrl
         ? `${enterpriseInstanceUrl}/api/v3/user`
         : undefined;
-      const callbackUrl = `${globalConfig.baseUrl}/${providerId}/handler/frame`;
+      const callbackUrl = customCallbackUrl ||
+       `${globalConfig.baseUrl}/${providerId}/handler/frame`;
 
       const catalogIdentityClient = new CatalogIdentityClient({
         catalogApi,