Allow Application Client Specific Customizations

Only installation clients may be configured with a rate limit checker.
This change allows for application vs installation client
customizations, so that the rate limit checker may be configured for the
installation client but not the application client.

Author: gilday

runtime/src/main/java/io/quarkiverse/githubapp/GitHubCustomizer.java

@@ -10,6 +10,11 @@ public interface GitHubCustomizer {
 
     /**
      * Customize the {@link GitHubBuilder} with various options.
+     *
+     * <p>
+     * These customizations are applied to both application and installation clients. Known cases of customizations that
+     * may be used with installation clients but not with application clients include configuring a rate limit checker. To use a
+     * different set of customizations for the application client, implement {@link #customizeApplicationClient(GitHubBuilder)}.
      * <p>
      * Note that customizations that use {@link GitHubBuilder#withAppInstallationToken(String)} and
      * {@link GitHubBuilder#withEndpoint(String)} are eventually overridden by the
@@ -21,4 +26,22 @@ public interface GitHubCustomizer {
      * @param builder to customize
      */
     void customize(GitHubBuilder builder);
+
+    /**
+     * Customize the {@link GitHubBuilder} with various options specifically for the application client. Default implementation
+     * delegates to {@link #customize(GitHubBuilder)} for backwards compatibility.
+     * <p>
+     * Note that customizations should never use {@link GitHubBuilder#withAppInstallationToken(String)}, because this is the
+     * application client. Customizations that use {@link GitHubBuilder#withJwtToken(String)} and
+     * {@link GitHubBuilder#withEndpoint(String)} are eventually overridden by the service.
+     *
+     * <p>
+     * To specify a custom endpoint, use configuration properties {@code quarkus.github-app.instance-endpoint} or
+     * {@code quarkus.github-app.rest-api-endpoint}.
+     *
+     * @param builder to customize
+     */
+    default void customizeApplicationClient(GitHubBuilder builder) {
+        customize(builder);
+    }
 }

runtime/src/main/java/io/quarkiverse/githubapp/runtime/github/GitHubService.java

@@ -292,7 +292,7 @@ private GitHub createApplicationGitHub() {
             final GitHubBuilder gitHubBuilder = new GitHubBuilder()
                     .withConnector(gitHubConnector);
             // apply customizations
-            githubCustomizer.customize(gitHubBuilder);
+            githubCustomizer.customizeApplicationClient(gitHubBuilder);
             // configure mandatory defaults
             gitHubBuilder
                     .withJwtToken(jwtToken)