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Resolver

The most common way to assign a specific resolver to a Field is to decorate your resolver function with the @Resolver decorator. Your function MUST BE compliant with the function signature and be async.

from tartiflette import Resolver

@Resolver("Query.hello")
async def my_hello_resolver(parent, args, context, info):
    return "Chuck"

Function signature

Every resolver in Tartiflette accepts four positional arguments:

(This signature is highly inspired by the GraphQL.js implementation)

async def my_hello_resolver(parent, args, context, info):
    pass

1. parent: The result returned by the resolver of the parent field. The initial_value of the execution is passed in the case of a top-level Query field.
2. args: A dict which contains the arguments passed for the field. (in the query). e.g. if the field was called with hello(name: "Chuck"), the args dict will be equals to { "name": "Chuck" }.
3. context: Dict shared by all resolvers, that can be different for each query. It acts as a container or a state for a specific request.
4. info: This argument CAN BE used for advanced use-cases; but it contains information about the execution state of the query.

Resolver info argument

The info argument contains the query's AST (Abstract Syntax Tree) and other execution details, which can be useful for middlewares and advanced use-cases.

Here are the available properties:

• query_field tartiflette.parser.NodeField - Contains the information of the field from the query's perspective.
• schema_field tartiflette.types.field.GraphQLField - Contains the information of the field from the schema's perspective (type, default values, and more.)
• schema tartiflette.schema.GraphQLSchema - Contains the GraphQL's server complete schema instance.
• path List[string] - Describes the path in the current query
• location tartiflette.types.location.Location - Describes the location in the query
• execution_ctx tartiflette.executor.types.ExecutionContext - Contains execution values (like errors).