fix: determine the suitable github api base url from repo url

Signed-off-by: Cheng Fang <cfang@redhat.com>

Author: chengfang

ext/git/creds.go

@@ -42,6 +42,7 @@ const (
 	// githubAccessTokenUsername is a username that is used to with the github access token
 	githubAccessTokenUsername = "x-access-token"
 	forceBasicAuthHeaderEnv   = "ARGOCD_GIT_AUTH_HEADER"
+	defaultGithubApiUrl = "https://api.github.com"
 )
 
 func init() {
@@ -443,12 +444,7 @@ func (g GitHubAppCreds) getAccessToken() (string, error) {
 		return itr.Token(ctx)
 	}
 
-	// GitHub API url
-	baseUrl := "https://api.github.com"
-	if g.baseURL != "" {
-		baseUrl = strings.TrimSuffix(g.baseURL, "/")
-	}
-
+	baseUrl := g.getBaseURL()
 	// Create a new GitHub transport
 	c := GetRepoHTTPClient(baseUrl, g.insecure, g, g.proxy)
 	itr, err := ghinstallation.New(c.Transport,
@@ -468,6 +464,27 @@ func (g GitHubAppCreds) getAccessToken() (string, error) {
 	return itr.Token(ctx)
 }
 
+func (g GitHubAppCreds) getBaseURL() string {
+	if g.baseURL != "" {
+		return strings.TrimSuffix(g.baseURL, "/")
+	}
+	if g.repoURL == "" {
+		return defaultGithubApiUrl
+	}
+
+	repoUrl, err := url.Parse(g.repoURL)
+	if err != nil || repoUrl.Hostname() == "github.com" {
+		return defaultGithubApiUrl
+	}
+
+	// GitHub Enterprise
+	scheme := repoUrl.Scheme
+	if scheme == "" {
+		scheme = "https"
+	}
+	return fmt.Sprintf("%s://%s/api/v3", scheme, repoUrl.Host)
+}
+
 func (g GitHubAppCreds) HasClientCert() bool {
 	return g.clientCertData != "" && g.clientCertKey != ""
 }

ext/git/creds_test.go

@@ -367,3 +367,27 @@ func TestGoogleCloudCreds_Environ_cleanup(t *testing.T) {
 	io.Close(closer)
 	assert.NotContains(t, store.creds, nonce)
 }
+
+func TestGitHubAppCreds_getBaseURL(t *testing.T) {
+	g := GitHubAppCreds{
+		appID:        123,
+		appInstallId: 1234,
+	}
+	assert.Equal(t, defaultGithubApiUrl, g.getBaseURL())
+
+	g.baseURL = "https://example.com/api"
+	assert.Equal(t, g.baseURL, g.getBaseURL())
+
+	g.baseURL = ""
+	g.repoURL = "https://github.com/org/repo"
+	assert.Equal(t, defaultGithubApiUrl, g.getBaseURL())
+
+	g.repoURL = "http://github.com/org/repo"
+	assert.Equal(t, defaultGithubApiUrl, g.getBaseURL())
+
+	g.repoURL = "https://example.com/org/repo"
+	assert.Equal(t, "https://example.com/api/v3", g.getBaseURL())
+
+	g.repoURL = "http://example.com/org/repo"
+	assert.Equal(t, "http://example.com/api/v3", g.getBaseURL())
+}