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DevSite Import: Batch #690
Description
Notice: This DevSite page will soon be deleted per b/133171590. Please add this sample to GitHub if it is relevant still:
https://developers.google.com/api-client-library/python/guide/batch
Batch
Each HTTP connection that your application makes results in a certain amount of overhead. This library supports batching, to allow your application to put several API calls into a single HTTP request. Examples of situations when you might want to use batching:
- You have many small requests to make and would like to minimize HTTP request overhead.
- A user made changes to data while your application was offline, so your application needs to synchronize its local data with the server by sending a lot of updates and deletes.
Note: You're limited to 1000 calls in a single batch request. If you need to make more calls than that, use multiple batch requests.
Note: You cannot use a media upload object in a batch request.
Details
You create batch requests by calling new_batch_http_request() on your service
object, which returns a
BatchHttpRequest
object, and then calling add() for each request you want to execute.
You may pass in a callback with each request that is called with the response to that request.
The callback function arguments are:
a unique request identifier for each API call,
a response object which contains the API call response,
and an exception object which may be set to an exception raised by the API call.
After you've added the requests, you call execute() to make the requests.
The execute() function blocks until all callbacks have been called.
In the following code snippet, two API requests are batched to a single HTTP request, and each API request is supplied a callback:
See below
You can also supply a single callback that gets called for each response:
See below
The
add()
method also allows you to supply a request_id parameter for each request.
These IDs are provided to the callbacks.
If you don't supply one, the library creates one for you.
The IDs must be unique for each API request,
otherwise add() raises an exception.
If you supply a callback to both new_batch_http_request() and add(), they both get called.
def list_animals(request_id, response, exception):
if exception is not None:
# Do something with the exception
pass
else:
# Do something with the response
pass
def list_farmers(request_id, response):
"""Do something with the farmers list response."""
pass
service = build('farm', 'v2')
batch = service.new_batch_http_request()
batch.add(service.animals().list(), callback=list_animals)
batch.add(service.farmers().list(), callback=list_farmers)
batch.execute(http=http)def insert_animal(request_id, response, exception):
if exception is not None:
# Do something with the exception
pass
else:
# Do something with the response
pass
service = build('farm', 'v2')
batch = service.new_batch_http_request(callback=insert_animal)
batch.add(service.animals().insert(name="sheep"))
batch.add(service.animals().insert(name="pig"))
batch.add(service.animals().insert(name="llama"))
batch.execute(http=http)
Activity
grant commentedon Jun 6, 2019
Before closing this issue, if adding this sample, see
https://b/65590380
docs: Adds docs folder. Fixes googleapis#669 Fixes googleapis#670 Fixes
grant commentedon Jun 26, 2019
The docs are now added to the
docs/folder.Fixed with #706.
stevenwu4 commentedon Jul 4, 2019
When I go to https://github.com/googleapis/google-api-python-client/tree/master/docs, I don't see a
batch.mdfile. The hyperlink in https://github.com/googleapis/google-api-python-client/blob/master/docs/performance.md under theBatchheader (https://github.com/googleapis/google-api-python-client/blob/master/docs/batch.md) results in a 404