Flow

Flow ties Executors together into a processing pipeline to perform a bigger task, like indexing or querying a dataset. Documents “flow” through the created pipeline and are processed by Executors. Flow also provides synchronization mechanisms to manage dependencies between executors and their order.

A Flow object has the following common methods:

Minimum working example

All-in-one style

from jina import Flow, Document, Executor, requests
class MyExecutor(Executor):
    @requests(on='/bar')
    def foo(self, docs, **kwargs):
        print(docs)
f = Flow().add(name='myexec1', uses=MyExecutor)
with f:
    f.post(on='/bar', inputs=Document(), on_done=print)

Flow-as-a-Service style

Server:

from jina import Flow, Executor, requests
class MyExecutor(Executor):
    @requests(on='/bar')
    def foo(self, docs, **kwargs):
        print(docs)
f = Flow(port_expose=12345).add(name='myexec1', uses=MyExecutor)
with f:
    f.block()

Client:

from jina import Client, Document
c = Client(port=12345)
c.post(on='/bar', inputs=Document(), on_done=print)

Load from YAML

my.yml:

jtype: Flow
executors:
  - name: myexec1
    uses: MyExecutor

from jina import Flow, Document
f = Flow.load_config('my.yml')
with f:
    f.post(on='/bar', inputs=Document(), on_done=print)

See Also

Document, Executor, and Flow are the three fundamental concepts in Jina.

• Document is the basic data type in Jina;

• Executor is how Jina processes Documents;

• Flow is how Jina streamlines and scales Executors.