This repository supports the Go runtime on App Engine, including both the standard App Engine and the “App Engine flexible environment” (formerly known as “Managed VMs”). It provides APIs for interacting with App Engine services. Its canonical import path is
See https://cloud.google.com/appengine/docs/go/ for more information.
File issue reports and feature requests on the Google App Engine issue tracker.
The top level directory of this repository is the
appengine package. It contains the basic APIs (e.g.
appengine.NewContext) that apply across APIs. Specific API packages are in subdirectories (e.g.
There is an
internal subdirectory that contains service protocol buffers, plus packages required for connectivity to make API calls. App Engine apps should not directly import any package under
This section describes how to update an older Go App Engine app to use these packages. A provided tool,
aefix, can help automate steps 2 and 3 (run
go get google.golang.org/appengine/cmd/aefix to install it), but read the details below since
aefix can't perform all the changes.
app.yaml file (and YAML files for modules) should have these new lines added:
The import paths for App Engine packages are now fully qualified, based at
google.golang.org/appengine. You will need to update your code to use import paths starting with that; for instance, code importing
appengine/datastore will now need to import
Most App Engine services are available with exactly the same API. A few APIs were cleaned up, and some are not available yet. This list summarises the differences:
appengine.Contexthas been replaced with the
appengine.Contextare now functions in
appengine.Timeouthas been removed. Use
appengine.Datacenternow takes a
datastore.PropertyLoadSaverhas been simplified to use slices in place of channels.
delay.Callnow returns an error.
search.FieldLoadSavernow handles document metadata.
urlfetch.Transportno longer has a Deadline field; set a deadline on the
aetestno longer declares its own Context type, and uses the standard one instead.
taskqueue.QueueStatsno longer takes a maxTasks argument. That argument has been deprecated and unused for a long time.
appengine.BackendInstancewere for the deprecated backends feature. Use
appengine/fileand parts of
appengine/blobstoreare deprecated. Use Google Cloud Storage if the feature you require is not present in the new blobstore package.
appengine/socketis not required on App Engine flexible environment / Managed VMs. Use the standard