2 files changed, 142 insertions, 0 deletions
diff --git a/lib/google_api/auth.rb b/lib/google_api/auth.rb
new file mode 100644
index 00000000000..99a82c849e0
--- /dev/null
+++ b/lib/google_api/auth.rb
@@ -0,0 +1,54 @@
+module GoogleApi
+  class Auth
+    attr_reader :access_token, :redirect_uri, :state
+
+    ConfigMissingError = Class.new(StandardError)
+
+    def initialize(access_token, redirect_uri, state: nil)
+      @access_token = access_token
+      @redirect_uri = redirect_uri
+      @state = state
+    end
+
+    def authorize_url
+      client.auth_code.authorize_url(
+        redirect_uri: redirect_uri,
+        scope: scope,
+        state: state # This is used for arbitary redirection
+      )
+    end
+
+    def get_token(code)
+      ret = client.auth_code.get_token(code, redirect_uri: redirect_uri)
+      return ret.token, ret.expires_at
+    end
+
+    protected
+
+    def scope
+      raise NotImplementedError
+    end
+
+    private
+
+    def config
+      Gitlab.config.omniauth.providers.find { |provider| provider.name == "google_oauth2" }
+    end
+
+    def client
+      return @client if defined?(@client)
+
+      unless config
+        raise ConfigMissingError
+      end
+
+      @client = ::OAuth2::Client.new(
+        config.app_id,
+        config.app_secret,
+        site: 'https://accounts.google.com',
+        token_url: '/o/oauth2/token',
+        authorize_url: '/o/oauth2/auth'
+      )
+    end
+  end
+end
diff --git a/lib/google_api/cloud_platform/client.rb b/lib/google_api/cloud_platform/client.rb
new file mode 100644
index 00000000000..a440a3e3562
--- /dev/null
+++ b/lib/google_api/cloud_platform/client.rb
@@ -0,0 +1,88 @@
+require 'google/apis/container_v1'
+
+module GoogleApi
+  module CloudPlatform
+    class Client < GoogleApi::Auth
+      DEFAULT_MACHINE_TYPE = 'n1-standard-1'.freeze
+      SCOPE = 'https://www.googleapis.com/auth/cloud-platform'.freeze
+      LEAST_TOKEN_LIFE_TIME = 10.minutes
+
+      class << self
+        def session_key_for_token
+          :cloud_platform_access_token
+        end
+
+        def session_key_for_expires_at
+          :cloud_platform_expires_at
+        end
+
+        def new_session_key_for_redirect_uri
+          SecureRandom.hex.tap do |state|
+            yield session_key_for_redirect_uri(state)
+          end
+        end
+
+        def session_key_for_redirect_uri(state)
+          "cloud_platform_second_redirect_uri_#{state}"
+        end
+      end
+
+      def scope
+        SCOPE
+      end
+
+      def validate_token(expires_at)
+        return false unless access_token
+        return false unless expires_at
+
+        # Making sure that the token will have been still alive during the cluster creation.
+        return false if token_life_time(expires_at) < LEAST_TOKEN_LIFE_TIME
+
+        true
+      end
+
+      def projects_zones_clusters_get(project_id, zone, cluster_id)
+        service = Google::Apis::ContainerV1::ContainerService.new
+        service.authorization = access_token
+
+        service.get_zone_cluster(project_id, zone, cluster_id)
+      end
+
+      def projects_zones_clusters_create(project_id, zone, cluster_name, cluster_size, machine_type:)
+        service = Google::Apis::ContainerV1::ContainerService.new
+        service.authorization = access_token
+
+        request_body = Google::Apis::ContainerV1::CreateClusterRequest.new(
+          {
+            "cluster": {
+              "name": cluster_name,
+              "initial_node_count": cluster_size,
+              "node_config": {
+                "machine_type": machine_type
+              }
+            }
+          } )
+
+        service.create_cluster(project_id, zone, request_body)
+      end
+
+      def projects_zones_operations(project_id, zone, operation_id)
+        service = Google::Apis::ContainerV1::ContainerService.new
+        service.authorization = access_token
+
+        service.get_zone_operation(project_id, zone, operation_id)
+      end
+
+      def parse_operation_id(self_link)
+        m = self_link.match(%r{projects/.*/zones/.*/operations/(.*)})
+        m[1] if m
+      end
+
+      private
+
+      def token_life_time(expires_at)
+        DateTime.strptime(expires_at, '%s').to_time.utc - Time.now.utc
+      end
+    end
+  end
+end