Hot Reload

While developing your Orchestration, you may want it to reload automatically as you change the YAML configuration.

For this you can use the Orchestration's reload argument to reload it with the updated configuration every time you change the YAML configuration.

{admonition}

:class: caution
This feature aims to let developers iterate faster while developing, but is not intended for production use.

{admonition}

:class: note
This feature requires `watchfiles>=0.18` to be installed.

{tab}

To see how this works, let's define a Deployment in `deployment.yml` with a `reload` option:
```yaml
jtype: Deployment
uses: ConcatenateTextExecutor
uses_with:
  text_to_concat: foo
with:
  port: 12345
  reload: True
```

Load and expose the Orchestration:

```python
import os
from jina import Deployment, Executor, requests
from docarray import DocList
from docarray.documents import TextDoc


class ConcatenateTextExecutor(Executor):
    @requests
    def foo(self, docs: DocList[TextDoc], **kwargs) -> DocList[TextDoc]:
        for doc in docs:
            doc.text += text_to_concat
        return docs


os.environ['JINA_LOG_LEVEL'] = 'DEBUG'


dep = Deployment.load_config('deployment.yml')

with dep:
    dep.block()
```

You can see that the Orchestration is running and serving:

```python
from jina import Client
from docarray import DocList
from docarray.documents import TextDoc

c = Client(port=12345)

print(c.post(on='/', inputs=DocList[TextDoc](TextDoc()), return_type=DocList[TextDoc])[0].text)
```

```text
foo
```

You can edit the Orchestration YAML file and save the changes:

```yaml
jtype: Deployment
uses: ConcatenateTextExecutor
uses_with:
  text_to_concat: bar
with:
  port: 12345
  reload: True
```

You should see the following in the Orchestration's logs:

```text
INFO   Deployment@28301 change in Deployment YAML deployment.yml observed, restarting Deployment                                                   
```

After this, the behavior of the Deployment's Executor will change:

```python
from jina import Client
from docarray import DocList
from docarray.documents import TextDoc

c = Client(port=12345)

print(c.post(on='/', inputs=DocList[TextDoc](TextDoc()), return_type=DocList[TextDoc])[0].text)
```

```text
bar
```

{tab}

To see how this works, let's define a Flow in `flow.yml` with a `reload` option:
```yaml
jtype: Flow
with:
  port: 12345
  reload: True
executors:
- name: exec1
  uses: ConcatenateTextExecutor
```

Load and expose the Orchestration:

```python
import os
from jina import Deployment, Executor, requests
from docarray import DocList
from docarray.documents import TextDoc


class ConcatenateTextExecutor(Executor):
    @requests
    def foo(self, docs: DocList[TextDoc], **kwargs) -> DocList[TextDoc]:
        for doc in docs:
            doc.text += text_to_concat
        return docs


os.environ['JINA_LOG_LEVEL'] = 'DEBUG'


f = Flow.load_config('flow.yml')

with f:
    f.block()
```

You can see that the Flow is running and serving:

```python
from jina import Client
from docarray import DocList
from docarray.documents import TextDoc

c = Client(port=12345)

print(c.post(on='/', inputs=DocList[TextDoc](TextDoc()), return_type=DocList[TextDoc])[0].text)
```

```text
add text
```

You can edit the Flow YAML file and save the changes:

```yaml
jtype: Flow
with:
  port: 12345
  reload: True
executors:
- name: exec1
  uses: ConcatenateTextExecutor
- name: exec2
  uses: ConcatenateTextExecutor
```

You should see the following in the Flow's logs:

```text
INFO   Flow@28301 change in Flow YAML flow.yml observed, restarting Flow                                                   
```

After this, the Flow will have two Executors with the new topology:

```python
from jina import Client
from docarray import DocList
from docarray.documents import TextDoc

c = Client(port=12345)

print(c.post(on='/', inputs=DocList[TextDoc](TextDoc()), return_type=DocList[TextDoc])[0].text)
```

```text
add text add text
```