Go App Engine packages
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
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
Updating a Go App Engine app
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
go get google.golang.org/appengine/cmd/aefix to install it), but
read the details below since
aefix can't perform all the changes.
1. Update YAML files (App Engine flexible environment / Managed VMs only)
app.yaml file (and YAML files for modules) should have these new lines added:
2. Update import paths
The import paths for App Engine packages are now fully qualified, based at
You will need to update your code to use import paths starting with that; for instance,
appengine/datastore will now need to import
3. Update code using deprecated, removed or modified APIs
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
- Logging methods that were on
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
- Most of
appengine/fileand parts of
appengine/blobstoreare deprecated. Use Google Cloud Storage instead.
appengine/socketis not required on App Engine flexible environment / Managed VMs. Use the standard