OSCAR API

To create an OSCAR service via the REST API, the POST method is used as shown in the following figure:

Two simple alternatives will be given on how to interact with the API to deploy a service on OSCAR.

• cURL

cURL, a command-line interface based HTTP client.

To deploy a service, you must have the FDL file that defines the service and the script that will be executed on it.

First, you need the credentials to access the cluster. This can be via an OIDC Token or basic authentication.

In that case, we give an example of creating the cowsay service using a cURL request with an OIDC Token. Basically, it involves embedding the FDL document as JSON-based document and the script inside a simple POST request.

curl -X POST "https://oscar-cluster-remote/system/services" \
     -H "Authorization: Bearer YOUR_TOKEN" \
     -H "Content-Type: application/json" \
     -d '{
  "name": "cowsay",
  "cpu": "1.0",
  "memory": "1Gi",
  "image": "ghcr.io/grycap/cowsay",
  "script": "#!/bin/sh\n\nif [ \"$INPUT_TYPE\" = \"json\" ]\nthen\n    jq \".message\" \"$INPUT_FILE_PATH\" -r | /usr/games/cowsay\nelse\n    cat \"$INPUT_FILE_PATH\" | /usr/games/cowsay\nfi",
  "log_level": "CRITICAL",
  "vo": "vo.ai4eosc.eu",
  "environment": { "Variables": { "INPUT_TYPE": "json" } }
}'

To see if the service is active and review its current configuration.

curl -H "Authorization: Bearer YOUR_TOKEN" \
     "https://oscar-cluster-remote/system/services/cowsay"

❗️ If you have basic authentication, replace -H "Authorization: Bearer ..." with -u "user:password", cURL automatically generates the Authorization: Basic [Base64] header.

• POSTMAN

Postman is one of the most popular tools developers use to test, document, and collaborate on APIs, especially REST APIs. The following is a brief example of deploying a service on an OSCAR cluster using its API.

To deploy a service, in this case the cowsay service, first a POST request is created and the API address for service deployment is entered. In this example, a remote cluster called oscar-cluster-remote is used.

The request must be configured for the type of authentication used. The figure shows both basic authentication (username and password) and authentication with an OIDC Token.

The request body is also configured, where the definition of the service to be deployed is entered. This information is taken from both the FDL file and the script. Once configured, the request can be sent to the OSCAR cluster.

With this, the service is deployed and ready to run (see Service Execution section)