title: “GraphQL querying support”
weight: 1
GraphQL is a query language for APIs and a runtime for fulfilling those queries with your existing data. It gives users the power to ask for exactly what they need and nothing more.
Enums
Enums represent possible sets of values for a field.
For example, the Node object has a field called status. The state is an enum (specifically, of type Status) because it may be UP , DRAINING or UNAVAILABLE.
Scalars
Scalars are primitive values: Int, Float, String, Boolean, or ID.
When calling the GraphQL API, you must specify nested subfield until you return only scalars.
Structure of the Schema
The structure of grid schema is as follows:
{
grid: {
uri,
totalSlots,
usedSlots,
nodes : [
{
id,
uri,
status,
maxSession,
capabilities
}
]
}
}
Querying GraphQL
The best way to query GraphQL is by using curl requests. GraphQL allows you to fetch only the data that you want, nothing more nothing less.
Some of the example GraphQL queries are given below. You can build your own queries as you like.
Querying the number of totalSlots and usedSlots in the grid :
curl -X POST -H "Content-Type: application/json" --data '{"query": "{ grid { totalSlots, usedSlots } }"}' -s <LINK_TO_GRAPHQL_ENDPOINT>
Generally on local machine the <LINK_TO_GRAPHQL_ENDPOINT> would be http://localhost:4444/graphql
Querying the capabilities of each node in the grid :
curl -X POST -H "Content-Type: application/json" --data '{"query": "{ grid { nodes { capabilities } } }"}' -s <LINK_TO_GRAPHQL_ENDPOINT>
Querying the status of each node in the grid :
curl -X POST -H "Content-Type: application/json" --data '{"query": "{ grid { nodes { status } } }"}' -s <LINK_TO_GRAPHQL_ENDPOINT>
Querying the URI of each node and the grid :
curl -X POST -H "Content-Type: application/json" --data '{"query": "{ grid { nodes { uri }, uri } }"}' -s <LINK_TO_GRAPHQL_ENDPOINT>
官方链接为：/documentation/grid/advanced_features/graphql_support/