@injectEnvironmentVariable Directive

The @injectEnvironmentVariable allows you to inject an environment variable into a VariableDefinition of your GraphQL Operations.

A potential use-case could be that you've got an application secret which you'd like to inject as an application ID. In this case, you don't want the user to be allowed to set the variable. Additionally, you might want to use different variables for different mutations or queries.

mutation ($loginID: String!, $applicationID: String! @injectEnvironmentVariable(name: "AUTH_APP_ID")) {
  authStart(input: { applicationId: $applicationID, loginId: $loginID }) {
    code
  }
}

The directive @injectEnvironmentVariable will enforce two things. For one, it will remove the annotated variable definition from the JSON Schema to validate the user-supplied variables. This means, the user is not allowed to set $applicationID in this scenario. Furthermore, the variable is not even visible to the user, it doesn't exist to them. Second, the variable is injected from the environment into the variables before executing the Operation.

@injectEnvironmentVariable accepts a second optional on: argument that might be used to inject a value into an specific field. Given the following type:

input createUserInput {
  email: String!
  environment: String!
  name: String!
}

We can use @injectEnvironmentVariable to set the value of environment using:

mutation ($input: createUserInput! @injectEnvironmentVariable(name: "ENVIRONMENT", on: "environment")) {
  users_Create($input) {
    id
    email
    name
  }
}

@injectEnvironmentVariable can be used multiple times on the same operation, injecting data into different fields. Additionally, @injectEnvironmentVariable can be combined with other directives for injecting or manipulating data like @fromClaim, @injectCurrentDateTime, @injectGeneratedUUID and @jsonSchema.