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PaddleOCR provides 2 service deployment methods:

- Based on **PaddleHub Serving**: Code path is `./deploy/hubserving`. Please follow this tutorial.
- Based on **PaddleServing**: Code path is `./deploy/pdserving`. Please refer to the [tutorial](../../ppocr/infer_deploy/paddle_server.en.md) for usage.

# Service deployment based on PaddleHub Serving

The hubserving service deployment directory includes seven service packages: text detection, text angle class, text recognition, text detection+text angle class+text recognition three-stage series connection, layout analysis, table recognition, and PP-Structure. Please select the corresponding service package to install and start the service according to your needs. The directory is as follows:

```text linenums="1"
deploy/hubserving/
  └─  ocr_det     text detection module service package
  └─  ocr_cls     text angle class module service package
  └─  ocr_rec     text recognition module service package
  └─  ocr_system  text detection+text angle class+text recognition three-stage series connection service package
  └─  structure_layout  layout analysis service package
  └─  structure_table  table recognition service package
  └─  structure_system  PP-Structure service package
  └─  kie_ser  KIE(SER) service package
  └─  kie_ser_re  KIE(SER+RE) service package
```

Each service pack contains 3 files. Take the 2-stage series connection service package as an example, the directory is as follows:

```text linenums="1"
deploy/hubserving/ocr_system/
  └─  __init__.py    Empty file, required
  └─  config.json    Configuration file, optional, passed in as a parameter when using configuration to start the service
  └─  module.py      Main module file, required, contains the complete logic of the service
  └─  params.py      Parameter file, required, including parameters such as model path, pre and post-processing parameters
```

## 1. Update

- 2022.10.09 add KIE services.
- 2022.08.23 add layout analysis services.
- 2022.03.30 add PP-Structure and table recognition services.
- 2022.05.05 add PP-OCRv3 text detection and recognition services.

## 2. Quick start service

The following steps take the 2-stage series service as an example. If only the detection service or recognition service is needed, replace the corresponding file path.

### 2.1 Install PaddleHub

```bash linenums="1"
pip3 install paddlehub==2.1.0 --upgrade
```

### 2.2 Download inference model

Before installing the service module, you need to prepare the inference model and put it in the correct path. By default, the PP-OCRv3 models are used, and the default model path is:

| Model | Path |
| ------- | - |
| text detection model | ./inference/PP-OCRv3_mobile_det_infer/ |
| text recognition model | ./inference/PP-OCRv3_mobile_rec_infer/ |
| text angle classifier | ./inference/ch_ppocr_mobile_v2.0_cls_infer/ |
| layout parse model | ./inference/picodet_lcnet_x1_0_fgd_layout_infer/ |
| tanle recognition | ./inference/ch_ppstructure_mobile_v2.0_SLANet_infer/ |
| KIE(SER) | ./inference/ser_vi_layoutxlm_xfund_infer/ |
| KIE(SER+RE) | ./inference/re_vi_layoutxlm_xfund_infer/ |

**The model path can be found and modified in `params.py`.**
More models provided by PaddleOCR can be obtained from the [model library](../../ppocr/model_list.en.md). You can also use models trained by yourself.

### 2.3 Install Service Module

PaddleOCR provides 5 kinds of service modules, install the required modules according to your needs.

- On the Linux platform(replace `/` with `\` if using Windows), the examples are as the following table:

| Service model | Command |
| text detection | `hub install deploy/hubserving/ocr_det` |
| text angle class: | `hub install deploy/hubserving/ocr_cls` |
| text recognition: | `hub install deploy/hubserving/ocr_rec` |
| 2-stage series: | `hub install deploy/hubserving/ocr_system` |
| table recognition | `hub install deploy/hubserving/structure_table` |
| PP-Structure | `hub install deploy/hubserving/structure_system` |
| KIE(SER) | `hub install deploy/hubserving/kie_ser` |
| KIE(SER+RE) | `hub install deploy/hubserving/kie_ser_re` |

### 2.4 Start service

#### 2.4.1 Start with command line parameters (CPU only)

**start command:**

```bash linenums="1"
hub serving start --modules Module1==Version1, Module2==Version2, ... \
                  --port 8866 \
                  --use_multiprocess \
                  --workers \
```

**Parameters:**
|parameters|usage|
|---|---|
|`--modules`/`-m`|PaddleHub Serving pre-installed model, listed in the form of multiple Module==Version key-value pairs<br>**When Version is not specified, the latest version is selected by default**|
|`--port`/`-p`|Service port, default is 8866|
|`--use_multiprocess`|Enable concurrent mode, by default using the single-process mode, this mode is recommended for multi-core CPU machines<br>**Windows operating system only supports single-process mode**|
|`--workers`|The number of concurrent tasks specified in concurrent mode, the default is `2*cpu_count-1`, where `cpu_count` is the number of CPU cores|

For example, start the 2-stage series service:

```bash linenums="1"
hub serving start -m ocr_system
```

This completes the deployment of a service API, using the default port number 8866.

#### 2.4.2 Start with configuration file（CPU and GPU）

**start command:**

```bash linenums="1"
hub serving start --config/-c config.json
```

In which the format of `config.json` is as follows:

```json
{
    "modules_info": {
        "ocr_system": {
            "init_args": {
                "version": "1.0.0",
                "use_gpu": true
            },
            "predict_args": {
            }
        }
    },
    "port": 8868,
    "use_multiprocess": false,
    "workers": 2
}
```

- The configurable parameters in `init_args` are consistent with the `_initialize` function interface in `module.py`.

  **When `use_gpu` is `true`, it means that the GPU is used to start the service**.
- The configurable parameters in `predict_args` are consistent with the `predict` function interface in `module.py`.

  **Note:**
  - When using the configuration file to start the service, other parameters will be ignored.
  - If you use GPU prediction (that is, `use_gpu` is set to `true`), you need to set the environment variable CUDA_VISIBLE_DEVICES before starting the service, such as:

    ```bash linenums="1"
    export CUDA_VISIBLE_DEVICES=0
    ```

  - **`use_gpu` and `use_multiprocess` cannot be `true` at the same time.**

For example, use GPU card No. 3 to start the 2-stage series service:

```bash linenums="1"
export CUDA_VISIBLE_DEVICES=3
hub serving start -c deploy/hubserving/ocr_system/config.json
```

## 3. Send prediction requests

After the service starts, you can use the following command to send a prediction request to obtain the prediction result:

```bash linenums="1"
python tools/test_hubserving.py --server_url=server_url --image_dir=image_path
```

Two parameters need to be passed to the script:

- **server_url**:service address, the format of which is
  `http://[ip_address]:[port]/predict/[module_name]`

  For example, if using the configuration file to start the text angle classification, text detection, text recognition, detection+classification+recognition 3 stages, table recognition and PP-Structure service,

  also modified the port for each service, then the `server_url` to send the request will be:

  ```text linenums="1"
  http://127.0.0.1:8865/predict/ocr_det
  http://127.0.0.1:8866/predict/ocr_cls
  http://127.0.0.1:8867/predict/ocr_rec
  http://127.0.0.1:8868/predict/ocr_system
  http://127.0.0.1:8869/predict/structure_table
  http://127.0.0.1:8870/predict/structure_system
  http://127.0.0.1:8870/predict/structure_layout
  http://127.0.0.1:8871/predict/kie_ser
  http://127.0.0.1:8872/predict/kie_ser_re
  ```

- **image_dir**:Test image path, which can be a single image path or an image directory path
- **visualize**:Whether to visualize the results, the default value is False
- **output**:The folder to save the Visualization result, the default value is `./hubserving_result`

Example:

```bash linenums="1"
python tools/test_hubserving.py --server_url=http://127.0.0.1:8868/predict/ocr_system --image_dir=./doc/imgs/ --visualize=false`
```

## 4. Returned result format

The returned result is a list. Each item in the list is a dictionary which may contain three fields. The information is as follows:

|field name|data type|description|
|----|----|----|
|angle|str|angle|
|text|str|text content|
|confidence|float|text recognition confidence|
|text_region|list|text location coordinates|
|html|str|table HTML string|
|regions|list|The result of layout analysis + table recognition + OCR, each item is a list<br>including `bbox` indicating area coordinates, `type` of area type and `res` of area results|
|layout|list|The result of layout analysis, each item is a dict, including `bbox` indicating area coordinates, `label` of area type|

The fields returned by different modules are different. For example, the results returned by the text recognition service module do not contain `text_region`, detailed table is as follows:

|field name/module name |ocr_det |ocr_cls |ocr_rec |ocr_system |structure_table |structure_system |structure_layout |kie_ser |kie_re |
|---                    |---     |---     |---     |---        |---             |---              |---              |---     |---    |
|angle                  |        |✔       |        |✔          |                |                 |                 |
|text                   |        |        |✔       |✔          |                |✔                |                 |✔       |✔      |
|confidence             |        |✔       |✔       |✔          |                |✔                |                 |✔       |✔      |
|text_region            |✔       |        |        |✔          |                |✔                |                 |✔       |✔      |
|html                   |        |        |        |           |✔               |✔                |                 |        |       |
|regions                |        |        |        |           |✔               |✔                |                 |        |       |
|layout                 |        |        |        |           |                |                 |✔                |        |       |
|ser_res                |        |        |        |           |                |                 |                 |✔       |       |
|re_res                 |        |        |        |           |                |                 |                 |        |✔      |

**Note:** If you need to add, delete or modify the returned fields, you can modify the file `module.py` of the corresponding module. For the complete process, refer to the user-defined modification service module in the next section.

## 5. User-defined service module modification

If you need to modify the service logic, the following steps are generally required (take the modification of `deploy/hubserving/ocr_system` for example):

1. Stop service:

```bash linenums="1"
hub serving stop --port/-p XXXX
```

2. Modify the code in the corresponding files under `deploy/hubserving/ocr_system`, such as `module.py` and `params.py`, to your actual needs.

   For example, if you need to replace the model used by the deployed service, you need to modify model path parameters `det_model_dir` and `rec_model_dir` in `params.py`. If you want to turn off the text direction classifier, set the parameter `use_angle_cls` to `False`.

   Of course, other related parameters may need to be modified at the same time. Please modify and debug according to the actual situation.

   **It is suggested to run `module.py` directly for debugging after modification before starting the service test.**

   **Note** The image input shape used by the PPOCR-v3 recognition model is `3, 48, 320`, so you need to modify `cfg.rec_image_shape = "3, 48, 320"` in `params.py`, if you do not use the PPOCR-v3 recognition model, then there is no need to modify this parameter.
3. (Optional) If you want to rename the module, the following lines should be modified:
   - [`ocr_system` within `from deploy.hubserving.ocr_system.params import read_params`](https://github.com/PaddlePaddle/PaddleOCR/blob/a923f35de57b5e378f8dd16e54d0a3e4f51267fd/deploy/hubserving/ocr_system/module.py#L35)
   - [`ocr_system` within `name="ocr_system",`](https://github.com/PaddlePaddle/PaddleOCR/blob/a923f35de57b5e378f8dd16e54d0a3e4f51267fd/deploy/hubserving/ocr_system/module.py#L39)
4. (Optional) It may require you to delete the directory `__pycache__` to force flush build cache of CPython:

   ```bash linenums="1"
   find deploy/hubserving/ocr_system -name '__pycache__' -exec rm -r {} \;
   ```

5. Install modified service module:

   ```bash linenums="1"
   hub install deploy/hubserving/ocr_system/
   ```

6. Restart service:

   ```bash linenums="1"
   hub serving start -m ocr_system
   ```
