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Note: ONNX Runtime Server is still in beta state. It's currently not ready for production environments.
How to Use ONNX Runtime Server REST API for Prediction
ONNX Runtime Server provides a REST API for prediction. The goal of the project is to make it easy to "host" any ONNX model as a RESTful service. The CLI command to start the service is shown below:
$ ./onnxruntime_server
the option '--model_path' is required but missing
Allowed options:
-h [ --help ] Shows a help message and exits
--log_level arg (=info) Logging level. Allowed options (case sensitive):
verbose, info, warning, error, fatal
--model_path arg Path to ONNX model
--address arg (=0.0.0.0) The base HTTP address
--http_port arg (=8001) HTTP port to listen to requests
--num_http_threads arg (=<# of your cpu cores>) Number of http threads
Note: The only mandatory argument for the program here is model_path
Start the Server
To host an ONNX model as a REST API server, run:
./onnxruntime_server --model_path /<your>/<model>/<path>
The prediction URL is in this format:
http://<your_ip_address>:<port>/v1/models/<your-model-name>/versions/<your-version>:predict
Note: Since we currently only support one model, the model name and version can be any string length > 0. In the future, model_names and versions will be verified.
Request and Response Payload
An HTTP request can be a Protobuf message in two formats: binary or JSON. The HTTP request header field Content-Type tells the server how to handle the request and thus it is mandatory for all requests. Requests missing Content-Type will be rejected as 400 Bad Request.
- For
"Content-Type: application/json", the payload will be deserialized as JSON string in UTF-8 format - For
"Content-Type: application/vnd.google.protobuf","Content-Type: application/x-protobuf"or"Content-Type: application/octet-stream", the payload will be consumed as protobuf message directly.
The Protobuf definition can be found here.
Inferencing
To send a request to the server, you can use any tool which supports making HTTP requests. Here is an example using curl:
curl -X POST -d "@predict_request_0.json" -H "Content-Type: application/json" http://127.0.0.1:8001/v1/models/mymodel/versions/3:predict
or
curl -X POST --data-binary "@predict_request_0.pb" -H "Content-Type: application/octet-stream" -H "Foo: 1234" http://127.0.0.1:8001/v1/models/mymodel/versions/3:predict
Clients can control the response type by setting the request with an Accept header field and the server will serialize in your desired format. The choices currently available are the same as the Content-Type header field.
Interactive tutorial notebook
A simple Jupyter notebook demonstrating the usage of ONNX Runtime server to host an ONNX model and perform inferencing can be found here.
Advanced Topics
Number of HTTP Threads
You can change this to optimize server utilization. The default is the number of CPU cores on the host machine.
Request ID and Client Request ID
For easy tracking of requests, we provide the following header fields:
x-ms-request-id: will be in the response header, no matter the request result. It will be a GUID/uuid with dash, e.g.72b68108-18a4-493c-ac75-d0abd82f0a11. If the request headers contain this field, the value will be ignored.x-ms-client-request-id: a field for clients to tracking their requests. The content will persist in the response headers.
Here is an example of a client sending a request:
Client Side
$ curl -v -X POST --data-binary "@predict_request_0.pb" -H "Content-Type: application/octet-stream" -H "Foo: 1234" -H "x-ms-client-request-id: my-request-001" -H "Accept: application/json" http://127.0.0.1:8001/v1/models/mymodel/versions/3:predict
Note: Unnecessary use of -X or --request, POST is already inferred.
* Trying 127.0.0.1...
* Connected to 127.0.0.1 (127.0.0.1) port 8001 (#0)
> POST /v1/models/mymodel/versions/3:predict HTTP/1.1
> Host: 127.0.0.1:8001
> User-Agent: curl/7.47.0
> Content-Type: application/octet-stream
> x-ms-client-request-id: my-request-001
> Accept: application/json
> Content-Length: 3179
> Expect: 100-continue
>
* Done waiting for 100-continue
* We are completely uploaded and fine
< HTTP/1.1 200 OK
< Content-Type: application/json
< x-ms-request-id: 72b68108-18a4-493c-ac75-d0abd82f0a11
< x-ms-client-request-id: my-request-001
< Content-Length: 159
<
* Connection #0 to host 127.0.0.1 left intact
{"outputs":{"Sample_Output_Name":{"dims":["1","10"],"dataType":1,"rawData":"6OpzRFquGsSFdM1FyAEnRFtRZcRa9NDEUBj0xI4ydsJIS0LE//CzxA==","dataLocation":"DEFAULT"}}}%
Server Side
And here is what the output on the server side looks like with logging level of verbose:
2019-04-04 23:48:26.395200744 [V:onnxruntime:72b68108-18a4-493c-ac75-d0abd82f0a11, predict_request_handler.cc:40 Predict] Name: mymodel Version: 3 Action: predict
2019-04-04 23:48:26.395289437 [V:onnxruntime:72b68108-18a4-493c-ac75-d0abd82f0a11, predict_request_handler.cc:46 Predict] x-ms-client-request-id: [my-request-001]
2019-04-04 23:48:26.395540707 [I:onnxruntime:InferenceSession, inference_session.cc:736 Run] Running with tag: 72b68108-18a4-493c-ac75-d0abd82f0a11
2019-04-04 23:48:26.395596858 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, inference_session.cc:976 CreateLoggerForRun] Created logger for run with id of 72b68108-18a4-493c-ac75-d0abd82f0a11
2019-04-04 23:48:26.395731391 [I:onnxruntime:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:42 Execute] Begin execution
2019-04-04 23:48:26.395763319 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:45 Execute] Size of execution plan vector: 12
2019-04-04 23:48:26.396228981 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:156 Execute] Releasing node ML values after computing kernel: Convolution28
2019-04-04 23:48:26.396580161 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:156 Execute] Releasing node ML values after computing kernel: Plus30
2019-04-04 23:48:26.396623732 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:197 ReleaseNodeMLValues] Releasing mlvalue with index: 10
2019-04-04 23:48:26.396878822 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:156 Execute] Releasing node ML values after computing kernel: ReLU32
2019-04-04 23:48:26.397091882 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:156 Execute] Releasing node ML values after computing kernel: Pooling66
2019-04-04 23:48:26.397126243 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:197 ReleaseNodeMLValues] Releasing mlvalue with index: 11
2019-04-04 23:48:26.397772701 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:156 Execute] Releasing node ML values after computing kernel: Convolution110
2019-04-04 23:48:26.397818174 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:197 ReleaseNodeMLValues] Releasing mlvalue with index: 13
2019-04-04 23:48:26.398060592 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:156 Execute] Releasing node ML values after computing kernel: Plus112
2019-04-04 23:48:26.398095300 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:197 ReleaseNodeMLValues] Releasing mlvalue with index: 14
2019-04-04 23:48:26.398257563 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:156 Execute] Releasing node ML values after computing kernel: ReLU114
2019-04-04 23:48:26.398426740 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:156 Execute] Releasing node ML values after computing kernel: Pooling160
2019-04-04 23:48:26.398466031 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:197 ReleaseNodeMLValues] Releasing mlvalue with index: 15
2019-04-04 23:48:26.398542823 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:156 Execute] Releasing node ML values after computing kernel: Times212_reshape0
2019-04-04 23:48:26.398599687 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:156 Execute] Releasing node ML values after computing kernel: Times212_reshape1
2019-04-04 23:48:26.398692631 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:156 Execute] Releasing node ML values after computing kernel: Times212
2019-04-04 23:48:26.398731471 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:197 ReleaseNodeMLValues] Releasing mlvalue with index: 17
2019-04-04 23:48:26.398832735 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:156 Execute] Releasing node ML values after computing kernel: Plus214
2019-04-04 23:48:26.398873229 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:197 ReleaseNodeMLValues] Releasing mlvalue with index: 19
2019-04-04 23:48:26.398922929 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:160 Execute] Fetching output.
2019-04-04 23:48:26.398956560 [V:VLOG1:72b68108-18a4-493c-ac75-d0abd82f0a11, sequential_executor.cc:163 Execute] Done with execution.