docs: add finetuner docs

docs/index.md

@@ -177,8 +177,8 @@ It means the client and the server are now connected. Well done!
 
 user-guides/client
 user-guides/server
+user-guides/finetuner
 user-guides/faq
-
 ```
 
 ```{toctree}

docs/user-guides/finetuner.md

@@ -0,0 +1,186 @@
+# Fine-tune Models
+
+Although CLIP-as-service has provided you a list of pre-trained models, you can also train your models. 
+This guide will show you how to use [Finetuner](https://finetuner.jina.ai) to fine-tune models and use them in CLIP-as-service.
+
+For installation and basic usage of Finetuner, please refer to [Finetuner documentation](https://finetuner.jina.ai).
+You can also [learn more details about fine-tuning CLIP](https://finetuner.jina.ai/tasks/text-to-image/).
+
+## Prepare Training Data
+
+Finetuner accepts training data and evaluation data in the form of [`DocumentArray`](https://docarray.jina.ai/fundamentals/documentarray/).
+The training data for CLIP is a list of (text, image) pairs.
+Each pair is store in a [`Document`](https://docarray.jina.ai/fundamentals/document/) which wraps two [`chunks`](https://docarray.jina.ai/fundamentals/document/nested/) with the `image` and `text` modality.
+You can push the resulting [`DocumentArray`](https://docarray.jina.ai/fundamentals/documentarray/) to the cloud using the [`.push`](https://docarray.jina.ai/api/docarray.array.document/?highlight=push#docarray.array.document.DocumentArray.push) method.
+
+We use [fashion captioning dataset](https://github.com/xuewyang/Fashion_Captioning) as a sample dataset in this tutorial.
+You can get the description and image url from the dataset: 
+
+| Description                                                                                                                           | Image URL                                                                                                                                                           |
+|---------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| subtly futuristic and edgy this liquid metal cuff bracelet is shaped from sculptural rectangular link                                 | [https://n.nordstrommedia.com/id/sr3/<br/>58d1a13f-b6b6-4e68-b2ff-3a3af47c422e.jpeg](https://n.nordstrommedia.com/id/sr3/58d1a13f-b6b6-4e68-b2ff-3a3af47c422e.jpeg) |
+| high quality leather construction defines a hearty boot one-piece on a tough lug sole                                                 | [https://n.nordstrommedia.com/id/sr3/<br/>21e7a67c-0a54-4d09-a4a4-6a0e0840540b.jpeg](https://n.nordstrommedia.com/id/sr3/21e7a67c-0a54-4d09-a4a4-6a0e0840540b.jpeg) |
+| this shimmering tricot knit tote is traced with decorative whipstitching and diamond cut chain the two hallmark of the falabella line | [https://n.nordstrommedia.com/id/sr3/<br/>1d8dd635-6342-444d-a1d3-4f91a9cf222b.jpeg](https://n.nordstrommedia.com/id/sr3/1d8dd635-6342-444d-a1d3-4f91a9cf222b.jpeg) |
+| ...                                                                                                                                   | ...                                                                                                                                                                 |
+
+You can use the following script to transform the first three entries of the dataset to a [`DocumentArray`](https://docarray.jina.ai/fundamentals/documentarray/) and push it to the cloud using the name `fashion-sample`.
+
+```python
+from docarray import Document, DocumentArray
+
+train_da = DocumentArray(
+    [
+        Document(
+            chunks=[
+                Document(
+                    content='subtly futuristic and edgy this liquid metal cuff bracelet is shaped from sculptural rectangular link',
+                    modality='text',
+                ),
+                Document(
+                    uri='https://n.nordstrommedia.com/id/sr3/58d1a13f-b6b6-4e68-b2ff-3a3af47c422e.jpeg',
+                    modality='image',
+                ),
+            ],
+        ),
+        Document(
+            chunks=[
+                Document(
+                    content='high quality leather construction defines a hearty boot one-piece on a tough lug sole',
+                    modality='text',
+                ),
+                Document(
+                    uri='https://n.nordstrommedia.com/id/sr3/21e7a67c-0a54-4d09-a4a4-6a0e0840540b.jpeg',
+                    modality='image',
+                ),
+            ],
+        ),
+        Document(
+            chunks=[
+                Document(
+                    content='this shimmering tricot knit tote is traced with decorative whipstitching and diamond cut chain the two hallmark of the falabella line',
+                    modality='text',
+                ),
+                Document(
+                    uri='https://n.nordstrommedia.com/id/sr3/1d8dd635-6342-444d-a1d3-4f91a9cf222b.jpeg',
+                    modality='image',
+                ),
+            ],
+        ),
+    ]
+)
+train_da.push('fashion-sample')
+```
+
+The full dataset has been converted to `clip-fashion-train-data` and `clip-fashion-eval-data` and pushed to the cloud.
+You can directly use them in Finetuner.
+
+## Start Finetuner
+
+You may now create and run a fine-tuning job after login to Jina ecosystem.
+
+```python
+import finetuner
+
+finetuner.login()
+run = finetuner.fit(
+    model='openai/clip-vit-base-patch32',
+    run_name='clip-fashion',
+    train_data='clip-fashion-train-data',
+    eval_data='clip-fashion-eval-data',  # optional
+    epochs=5,
+    learning_rate=1e-5,
+    loss='CLIPLoss',
+    cpu=False,
+)
+```
+
+After the job started, you may use [`.status`](https://finetuner.jina.ai/api/finetuner.run/#finetuner.run.Run.status) to check the status of the job.
+
+```python
+import finetuner
+
+finetuner.login()
+run = finetuner.get_run('clip-fashion')
+print(run.status())
+```
+
+When the status is `FINISHED`, you can download the tuned model to your local machine.
+
+```python
+import finetuner
+
+finetuner.login()
+run = finetuner.get_run('clip-fashion')
+run.save_artifact('clip-model')
+```
+
+You should now get a zip file containing the tuned model named `clip-fashion.zip` under the folder `clip-model`.
+
+## Use the Model
+
+After unzipping the model you get from the previous step, a folder with the following structure will be generated:
+
+```text
+.
+└── clip-fashion/
+    ├── config.yml
+    ├── metadata.yml
+    ├── metrics.yml
+    └── models/
+        ├── clip-text/
+        │   ├── metadata.yml
+        │   └── model.onnx
+        ├── clip-vision/
+        │   ├── metadata.yml
+        │   └── model.onnx
+        └── input-map.yml
+```
+
+Since the tuned model generated from Finetuner contains richer information such as metadata and config, we now transform it to simpler structure used by CLIP-as-service.
+
+* First create a new folder named `clip-fashion-cas` or anything you like. This will be the storage of the models to use in CLIP-as-service.
+
+* Second copy and move `clip-fashion/models/clip-text/model.onnx` to `clip-fashion-cas` and rename it to `textual.onnx`.
+
+* Similarly, copy and move `clip-fashion/models/clip-vision/model.onnx` to `clip-fashion-cas` and rename it to `visual.onnx`.
+
+This is the expected structure of `clip-fashion-cas`:
+
+```text
+.
+└── clip-fashion-cas/
+    ├── textual.onnx
+    └── visual.onnx
+```
+
+In order to use fine-tuned model, create a custom YAML file `finetuned_clip.yml` like below. Learn more about [Flow YAML configuration](https://docs.jina.ai/fundamentals/flow/yaml-spec/) and [`clip_server` YAML configuration](https://clip-as-service.jina.ai/user-guides/server/#yaml-config).
+
+```yaml
+jtype: Flow
+version: '1'
+with:
+  port: 51000
+executors:
+  - name: clip_o
+    uses:
+      jtype: CLIPEncoder
+      metas:
+        py_modules:
+          - clip_server.executors.clip_onnx
+      with:
+        name: ViT-B/32
+        model_path: 'clip-fashion-cas' # path to clip-fashion-cas
+    replicas: 1
+```
+
+```{warning}
+Note that Finetuner only support ViT-B/32 CLIP model currently. The model name should match the fine-tuned model, or you will get incorrect output.
+```
+
+You can now start the `clip_server` using fine-tuned model to get a performance boost:
+
+```bash
+python -m clip_server finetuned_clip.yml
+```
+
+That's it, enjoy 🚀