1 files changed, 136 insertions, 0 deletions
diff --git a/lib/container_registry/base_client.rb b/lib/container_registry/base_client.rb
new file mode 100644
index 00000000000..22d4510fe71
--- /dev/null
+++ b/lib/container_registry/base_client.rb
@@ -0,0 +1,136 @@
+# frozen_string_literal: true
+
+require 'faraday'
+require 'faraday_middleware'
+require 'digest'
+
+module ContainerRegistry
+  class BaseClient
+    DOCKER_DISTRIBUTION_MANIFEST_V2_TYPE = 'application/vnd.docker.distribution.manifest.v2+json'
+    DOCKER_DISTRIBUTION_MANIFEST_LIST_V2_TYPE = 'application/vnd.docker.distribution.manifest.list.v2+json'
+    OCI_MANIFEST_V1_TYPE = 'application/vnd.oci.image.manifest.v1+json'
+    CONTAINER_IMAGE_V1_TYPE = 'application/vnd.docker.container.image.v1+json'
+
+    ACCEPTED_TYPES = [DOCKER_DISTRIBUTION_MANIFEST_V2_TYPE, OCI_MANIFEST_V1_TYPE].freeze
+    ACCEPTED_TYPES_RAW = [DOCKER_DISTRIBUTION_MANIFEST_V2_TYPE, OCI_MANIFEST_V1_TYPE, DOCKER_DISTRIBUTION_MANIFEST_LIST_V2_TYPE].freeze
+
+    RETRY_EXCEPTIONS = [Faraday::Request::Retry::DEFAULT_EXCEPTIONS, Faraday::ConnectionFailed].flatten.freeze
+    RETRY_OPTIONS = {
+      max: 1,
+      interval: 5,
+      exceptions: RETRY_EXCEPTIONS
+    }.freeze
+
+    ERROR_CALLBACK_OPTIONS = {
+      callback: -> (env, exception) do
+        Gitlab::ErrorTracking.log_exception(
+          exception,
+          class: name,
+          url: env[:url]
+        )
+      end
+    }.freeze
+
+    # Taken from: FaradayMiddleware::FollowRedirects
+    REDIRECT_CODES = Set.new [301, 302, 303, 307]
+
+    class << self
+      private
+
+      def with_dummy_client(return_value_if_disabled: nil)
+        registry_config = Gitlab.config.registry
+        unless registry_config.enabled && registry_config.api_url.present?
+          return return_value_if_disabled
+        end
+
+        token = Auth::ContainerRegistryAuthenticationService.access_token([], [])
+        yield new(registry_config.api_url, token: token)
+      end
+    end
+
+    def initialize(base_uri, options = {})
+      @base_uri = base_uri
+      @options = options
+    end
+
+    private
+
+    def faraday(timeout_enabled: true)
+      @faraday ||= faraday_base(timeout_enabled: timeout_enabled) do |conn|
+        initialize_connection(conn, @options, &method(:configure_connection))
+      end
+    end
+
+    def faraday_base(timeout_enabled: true, &block)
+      request_options = timeout_enabled ? Gitlab::HTTP::DEFAULT_TIMEOUT_OPTIONS : nil
+
+      Faraday.new(
+        @base_uri,
+        headers: { user_agent: "GitLab/#{Gitlab::VERSION}" },
+        request: request_options,
+        &block
+      )
+    end
+
+    def initialize_connection(conn, options)
+      conn.request :json
+
+      if options[:user] && options[:password]
+        conn.request(:basic_auth, options[:user].to_s, options[:password].to_s)
+      elsif options[:token]
+        conn.request(:authorization, :bearer, options[:token].to_s)
+      end
+
+      yield(conn) if block_given?
+
+      conn.request(:retry, RETRY_OPTIONS)
+      conn.request(:gitlab_error_callback, ERROR_CALLBACK_OPTIONS)
+      conn.adapter :net_http
+    end
+
+    def response_body(response, allow_redirect: false)
+      if allow_redirect && REDIRECT_CODES.include?(response.status)
+        response = redirect_response(response.headers['location'])
+      end
+
+      response.body if response && response.success?
+    end
+
+    def redirect_response(location)
+      return unless location
+
+      uri = URI(@base_uri).merge(location)
+      raise ArgumentError, "Invalid scheme for #{location}" unless %w[http https].include?(uri.scheme)
+
+      faraday_redirect.get(uri)
+    end
+
+    def configure_connection(conn)
+      conn.headers['Accept'] = ACCEPTED_TYPES
+
+      conn.response :json, content_type: 'application/json'
+      conn.response :json, content_type: 'application/vnd.docker.distribution.manifest.v1+prettyjws'
+      conn.response :json, content_type: 'application/vnd.docker.distribution.manifest.v1+json'
+      conn.response :json, content_type: DOCKER_DISTRIBUTION_MANIFEST_V2_TYPE
+      conn.response :json, content_type: OCI_MANIFEST_V1_TYPE
+    end
+
+    # Create a new request to make sure the Authorization header is not inserted
+    # via the Faraday middleware
+    def faraday_redirect
+      @faraday_redirect ||= faraday_base do |conn|
+        conn.request :json
+
+        conn.request(:retry, RETRY_OPTIONS)
+        conn.request(:gitlab_error_callback, ERROR_CALLBACK_OPTIONS)
+        conn.adapter :net_http
+      end
+    end
+
+    def delete_if_exists(path)
+      result = faraday.delete(path)
+
+      result.success? || result.status == 404
+    end
+  end
+end