First API (without API Deployer)

This page will guide you through the process of creating and deploying your first API service. For this example, we’ll use a prediction endpoint, used to expose as a REST API service a model developed using the DSS visual machine learning component.

The steps to expose a prediction model are:

This section assumes that you already have installed and started a DSS API node instance. Please see Installing an API node if that’s not yet the case.

Create the model

The first step is to create a model and deploy it to the Flow. This is done using the regular Machine Learning component of DSS. Please refer to the Machine Learning Tutorial and to Machine learning for more information.

Create the API Service

There are two ways you can create your API Service:

Create directly from the Flow

Note

This method can only be used for prediction endpoints, and cannot be used for other kinds of endpoints

  • In the Flow, select your model, then select “Create API” from the Actions panel
  • Give an identifier to your API Service. This identifier will appear in the URL used to query the API
  • Within this API Service, give an identifier to the endpoint. A service can contain multiple endpoints (to manage several models at once, or perform different functions)

The URL to query the API will be like /public/api/v1/<service_id>/<endpoint_id>/predict.

Click Append, and you are taken to the newly created API Service in the API Designer component.

Create the API service then the endpoint in API Designer

  • Go to the project homepage
  • Go to the API Designer and create a new service
  • Give an identifier to your API Service. This identifier will appear in the URL used to query the API
  • At this point, the API Service is created but does not yet have any endpoint; it does not yet expose any model. See Concepts for what endpoints are.
  • Create a new endpoint of type “Prediction”. Give an identifier to the endpoint. A service can contain multiple endpoints (to manage several models at once, or perform different functions)
  • Select the model to use for this endpoint. This must be a saved model (i.e. a model which has been deployed to the Flow).

The URL to query the API will be like /public/api/v1/<service_id>/<endpoint_id>/predict.

Click Append, and you are taken to the newly created API Service in the API Designer component.

For a simple service, that’s it! You don’t need any further configuration.

(Optional) Add test queries

It’s a good practice to add a few test queries to check that your endpoint is working as expected.

  • Go to Test queries
  • Select add test queries. You can select a “test” dataset to automatically create test queries from the rows of this dataset
  • Click on “Run test queries”
  • You should see the prediction associated with each test query

Create a version and transfer the package

Now that your service is properly configured in DSS, the next step is to create a new version (i.e. snapshot), and to download the associated version package (See Concepts).

  • Click on the “Prepare package” button
  • DSS asks you for a package version number. This version number will be the identifier of this generation for all interactions with the API node. It is recommended that you use a meaningful short name like v4-new-customer-features. You want to be able to remember what was new in that generation (think of it as a Git tag)
  • Go to the packages tab.
  • Click on the Download button

The package file (a .zip file) is downloaded to your computer. Upload the zip file to each host running an API node.

Create the service in the API node

We are now going to actually activate the package in the API node.

  • Go to the API node directory
  • Create the service: run the following command
./bin/apinode-admin service-create <SERVICE_ID>
  • Then, we need to import the package zip file:
./bin/apinode-admin service-import-generation <SERVICE_ID> <PATH TO ZIP FILE>

Now, the API node has unzipped the package in its own folders, and is ready to start using it. At that point, however, the new generation is only available, it’s not active. In other words, if we were to perform an API query, it would fail because no generation is currently active.

./bin/apinode-admin service-switch-to-newest <SERVICE_ID>

When this command returns, the API node service is now active, running on the latest (currently the only) generation of the package.

Perform a test query

We can now actually perform a prediction. Query the following URL (using your browser for example):

http://APINODE_SERVER:APINODE_PORT/public/api/v1/SERVICE_ID/ENDPOINT_ID/predict-simple?feat1=val1&feat2=val2

where feat1 and feat2 are the names of features (columns) in your train set.

You should receive a JSON reply with a result section containing your prediction (and probabilities in case of a classification model).

Perform real queries

Once you have confirmed that your service endpoint works, you can actually use the API to integrate in your application.

See API node user API for more information.

Next steps

Head over to the documentation page for each type of endpoint to get more information about how to use each one of them.