Support optional/configurable IAMEndpoint for Minio Client (#32581) (#32581)

Targeting issue #32271

This modification allows native Kubernetes + AWS (EKS) authentication
with the Minio client, to Amazon S3 using the IRSA role assigned to a
Service account by replacing the hard coded reference to the
`DefaultIAMRoleEndpoint` with an optional configurable endpoint.

Internally, Minio's `credentials.IAM` provider implements a discovery
flow for IAM Endpoints if it is not set.

For backwards compatibility: 
- We have added a configuration mechanism for an `IamEndpoint` to retain
the unit test safety in `minio_test.go`.
- We believe existing clients will continue to function the same without
needing to provide a new config property since the internals of Minio
client also often resolve to the `http://169.254.169.254` default
endpoint that was being hard coded before

To test, we were able to build a docker image from source and, observe
it choosing the expected IAM endpoint, and see files uploaded via the
client.

5 files changed, 46 insertions, 11 deletions

diff --git a/custom/conf/app.example.ini b/custom/conf/app.example.ini
index ef5684237d..c3b78e60bb 100644
--- a/custom/conf/app.example.ini
+++ b/custom/conf/app.example.ini
@@ -1944,6 +1944,13 @@ LEVEL = Info
 ;; Minio secretAccessKey to connect only available when STORAGE_TYPE is `minio`
 ;MINIO_SECRET_ACCESS_KEY =
 ;;
+;; Preferred IAM Endpoint to override Minio's default IAM Endpoint resolution only available when STORAGE_TYPE is `minio`. 
+;; If not provided and STORAGE_TYPE is `minio`, will search for and derive endpoint from known environment variables 
+;; (AWS_CONTAINER_AUTHORIZATION_TOKEN, AWS_CONTAINER_AUTHORIZATION_TOKEN_FILE, AWS_CONTAINER_CREDENTIALS_RELATIVE_URI, 
+;; AWS_CONTAINER_CREDENTIALS_FULL_URI, AWS_WEB_IDENTITY_TOKEN_FILE, AWS_ROLE_ARN, AWS_ROLE_SESSION_NAME, AWS_REGION), 
+;; or the DefaultIAMRoleEndpoint if not provided otherwise.
+;MINIO_IAM_ENDPOINT =
+;; 
 ;; Minio bucket to store the attachments only available when STORAGE_TYPE is `minio`
 ;MINIO_BUCKET = gitea
 ;;
@@ -2688,6 +2695,13 @@ LEVEL = Info
 ;; Minio secretAccessKey to connect only available when STORAGE_TYPE is `minio`
 ;MINIO_SECRET_ACCESS_KEY =
 ;;
+;; Preferred IAM Endpoint to override Minio's default IAM Endpoint resolution only available when STORAGE_TYPE is `minio`. 
+;; If not provided and STORAGE_TYPE is `minio`, will search for and derive endpoint from known environment variables 
+;; (AWS_CONTAINER_AUTHORIZATION_TOKEN, AWS_CONTAINER_AUTHORIZATION_TOKEN_FILE, AWS_CONTAINER_CREDENTIALS_RELATIVE_URI, 
+;; AWS_CONTAINER_CREDENTIALS_FULL_URI, AWS_WEB_IDENTITY_TOKEN_FILE, AWS_ROLE_ARN, AWS_ROLE_SESSION_NAME, AWS_REGION), 
+;; or the DefaultIAMRoleEndpoint if not provided otherwise.
+;MINIO_IAM_ENDPOINT =
+;;
 ;; Minio bucket to store the attachments only available when STORAGE_TYPE is `minio`
 ;MINIO_BUCKET = gitea
 ;;
diff --git a/modules/setting/storage.go b/modules/setting/storage.go
index d6f7672b61..d3d1fb9f30 100644
--- a/modules/setting/storage.go
+++ b/modules/setting/storage.go
@@ -43,6 +43,7 @@ type MinioStorageConfig struct {
 	Endpoint           string `ini:"MINIO_ENDPOINT" json:",omitempty"`
 	AccessKeyID        string `ini:"MINIO_ACCESS_KEY_ID" json:",omitempty"`
 	SecretAccessKey    string `ini:"MINIO_SECRET_ACCESS_KEY" json:",omitempty"`
+	IamEndpoint        string `ini:"MINIO_IAM_ENDPOINT" json:",omitempty"`
 	Bucket             string `ini:"MINIO_BUCKET" json:",omitempty"`
 	Location           string `ini:"MINIO_LOCATION" json:",omitempty"`
 	BasePath           string `ini:"MINIO_BASE_PATH" json:",omitempty"`
diff --git a/modules/setting/storage_test.go b/modules/setting/storage_test.go
index 44a5de6826..8ee37fd2b6 100644
--- a/modules/setting/storage_test.go
+++ b/modules/setting/storage_test.go
@@ -470,6 +470,19 @@ MINIO_BASE_PATH = /prefix
 	cfg, err = NewConfigProviderFromData(`
 [storage]
 STORAGE_TYPE = minio
+MINIO_IAM_ENDPOINT = 127.0.0.1
+MINIO_USE_SSL = true
+MINIO_BASE_PATH = /prefix
+`)
+	assert.NoError(t, err)
+	assert.NoError(t, loadRepoArchiveFrom(cfg))
+	assert.EqualValues(t, "127.0.0.1", RepoArchive.Storage.MinioConfig.IamEndpoint)
+	assert.EqualValues(t, true, RepoArchive.Storage.MinioConfig.UseSSL)
+	assert.EqualValues(t, "/prefix/repo-archive/", RepoArchive.Storage.MinioConfig.BasePath)
+
+	cfg, err = NewConfigProviderFromData(`
+[storage]
+STORAGE_TYPE = minio
 MINIO_ACCESS_KEY_ID = my_access_key
 MINIO_SECRET_ACCESS_KEY = my_secret_key
 MINIO_USE_SSL = true
diff --git a/modules/storage/minio.go b/modules/storage/minio.go
index 8acb7b0354..6b92be61fb 100644
--- a/modules/storage/minio.go
+++ b/modules/storage/minio.go
@@ -97,7 +97,7 @@ func NewMinioStorage(ctx context.Context, cfg *setting.Storage) (ObjectStorage,
 	}
 
 	minioClient, err := minio.New(config.Endpoint, &minio.Options{
-		Creds:        buildMinioCredentials(config, credentials.DefaultIAMRoleEndpoint),
+		Creds:        buildMinioCredentials(config),
 		Secure:       config.UseSSL,
 		Transport:    &http.Transport{TLSClientConfig: &tls.Config{InsecureSkipVerify: config.InsecureSkipVerify}},
 		Region:       config.Location,
@@ -164,7 +164,7 @@ func (m *MinioStorage) buildMinioDirPrefix(p string) string {
 	return p
 }
 
-func buildMinioCredentials(config setting.MinioStorageConfig, iamEndpoint string) *credentials.Credentials {
+func buildMinioCredentials(config setting.MinioStorageConfig) *credentials.Credentials {
 	// If static credentials are provided, use those
 	if config.AccessKeyID != "" {
 		return credentials.NewStaticV4(config.AccessKeyID, config.SecretAccessKey, "")
@@ -184,7 +184,9 @@ func buildMinioCredentials(config setting.MinioStorageConfig, iamEndpoint string
 		&credentials.FileAWSCredentials{},
 		// read IAM role from EC2 metadata endpoint if available
 		&credentials.IAM{
-			Endpoint: iamEndpoint,
+			// passing in an empty Endpoint lets the IAM Provider
+			// decide which endpoint to resolve internally
+			Endpoint: config.IamEndpoint,
 			Client: &http.Client{
 				Transport: http.DefaultTransport,
 			},
diff --git a/modules/storage/minio_test.go b/modules/storage/minio_test.go
index 6eb03c4a45..395da051e8 100644
--- a/modules/storage/minio_test.go
+++ b/modules/storage/minio_test.go
@@ -107,8 +107,9 @@ func TestMinioCredentials(t *testing.T) {
 		cfg := setting.MinioStorageConfig{
 			AccessKeyID:     ExpectedAccessKey,
 			SecretAccessKey: ExpectedSecretAccessKey,
+			IamEndpoint:     FakeEndpoint,
 		}
-		creds := buildMinioCredentials(cfg, FakeEndpoint)
+		creds := buildMinioCredentials(cfg)
 		v, err := creds.Get()
 
 		assert.NoError(t, err)
@@ -117,13 +118,15 @@ func TestMinioCredentials(t *testing.T) {
 	})
 
 	t.Run("Chain", func(t *testing.T) {
-		cfg := setting.MinioStorageConfig{}
+		cfg := setting.MinioStorageConfig{
+			IamEndpoint: FakeEndpoint,
+		}
 
 		t.Run("EnvMinio", func(t *testing.T) {
 			t.Setenv("MINIO_ACCESS_KEY", ExpectedAccessKey+"Minio")
 			t.Setenv("MINIO_SECRET_KEY", ExpectedSecretAccessKey+"Minio")
 
-			creds := buildMinioCredentials(cfg, FakeEndpoint)
+			creds := buildMinioCredentials(cfg)
 			v, err := creds.Get()
 
 			assert.NoError(t, err)
@@ -135,7 +138,7 @@ func TestMinioCredentials(t *testing.T) {
 			t.Setenv("AWS_ACCESS_KEY", ExpectedAccessKey+"AWS")
 			t.Setenv("AWS_SECRET_KEY", ExpectedSecretAccessKey+"AWS")
 
-			creds := buildMinioCredentials(cfg, FakeEndpoint)
+			creds := buildMinioCredentials(cfg)
 			v, err := creds.Get()
 
 			assert.NoError(t, err)
@@ -144,11 +147,11 @@ func TestMinioCredentials(t *testing.T) {
 		})
 
 		t.Run("FileMinio", func(t *testing.T) {
-			t.Setenv("MINIO_SHARED_CREDENTIALS_FILE", "testdata/minio.json")
 			// prevent loading any actual credentials files from the user
+			t.Setenv("MINIO_SHARED_CREDENTIALS_FILE", "testdata/minio.json")
 			t.Setenv("AWS_SHARED_CREDENTIALS_FILE", "testdata/fake")
 
-			creds := buildMinioCredentials(cfg, FakeEndpoint)
+			creds := buildMinioCredentials(cfg)
 			v, err := creds.Get()
 
 			assert.NoError(t, err)
@@ -161,7 +164,7 @@ func TestMinioCredentials(t *testing.T) {
 			t.Setenv("MINIO_SHARED_CREDENTIALS_FILE", "testdata/fake.json")
 			t.Setenv("AWS_SHARED_CREDENTIALS_FILE", "testdata/aws_credentials")
 
-			creds := buildMinioCredentials(cfg, FakeEndpoint)
+			creds := buildMinioCredentials(cfg)
 			v, err := creds.Get()
 
 			assert.NoError(t, err)
@@ -187,7 +190,9 @@ func TestMinioCredentials(t *testing.T) {
 			defer server.Close()
 
 			// Use the provided EC2 Instance Metadata server
-			creds := buildMinioCredentials(cfg, server.URL)
+			creds := buildMinioCredentials(setting.MinioStorageConfig{
+				IamEndpoint: server.URL,
+			})
 			v, err := creds.Get()
 
 			assert.NoError(t, err)