Monitor and Control Simulations through GraphQL

A simulation in Alchemist can be monitored and controlled by a set of GraphQL APIs which provide a standard and flexible way to query the system.

In the following guide, you will learn how to use the API service for having a simple overview of the running simulation thanks to the playground GraphiQL with the ability to control the simulation, or to develop an Alchemist sub-module that uses the API service.

Use GraphQL service inside Alchemist

In order to attach the GraphQL API service to a simulation, you must specify the GraphQLMonitor in the simulation’s YAML file, providing the server’s host and port (if not specified, default URL is: 127.0.0.1:8081) as shown in the following example:

monitors:
  type: GraphQLMonitor
  parameters:
    host: <my-custom-host>
    port: <my-custom-port>

Once the YAML file is ready, the simulation can be started as usual.

Simulation’s overview in the Web Browser

Once the simulation is up and running, you can visit on your local web browser the URL: http://<my-custom-host>:<my-custom-port>/graphiql. In this GraphiQL playground you will be able to lookup all the operations and types structure that are defined in the GraphQL schema, thanks to the documentation on the sidebar, or execute operations defining the structure of the data that you will need.