igalshilman opened a new pull request #5:
URL: https://github.com/apache/flink-statefun-playground/pull/5
copied from the `README.md`:
# The Greeter Example
This is a simple example of a stateful functions application implemented in
`Python`.
In this example, we imagine a service that computes personalized greetings.
Our service, consist out of the following components:
* `kafka ingress` - This component forwards messages produced to the `names`
kafka topic,
to the `person` stateful function. Messages produced to this topic has the
following
schema `{ "name" : "bob"}`.
* `person` - This function is triggered by the ingress defined above.
This function keeps track of the number of visits, and triggers the next
functions:
* `greeter` - This function, computes a personalized greeting, based on the
name and the number
of visits of that user. The output of that computation is forward to a Kafka
egress defined below.
* `kafka egress` - This wraps a Kafka producer that emits `utf-8` greetings
to the `greetings` Kafka topic.
## Running the example
```
docker-compose build
docker-compose up
```
To observe the customized greeting, as they appear in the `greetings` Kafka
topic, run in a separate terminal:
```
docker-compose exec kafka kafka-console-consumer \
--bootstrap-server kafka:9092 \
--isolation-level read_committed \
--from-beginning \
--topic greetings
```
Try adding few more input lines to [input-example.json](input-example.json),
and restart
the producer service.
```
docker-compose restart producer
```
Feeling curious? add the following print to the `person` function at
[server.py](server.py):
```print(f"Hello there {context.address.id}!", flush=True)```.
Then, rebuild and restart only the `functions` service.
```
docker-compose build functions
docker-compose up functions
```
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