WPGraphQL Logging - Create Request Lifecycle

[colinmurphy]

Overview

As per RFC #152 (comment) we need to develop a request lifecycle for a WPGraphQL Query in which we allow listeners to capture key data.

This is part of the logging functionality to capture and log the data before the end of the request lifecycle.

Criteria

• Research best practices for event/subscription architecture
• Review the WPGraphQL lifecycle and identify key hooks/filters needed for the lifecycle
• Architecture the Request lifecycle and also how listeners can capture data
• Develop Request Lifecycle
• Unit tests, documentation, QA

[colinmurphy]

@wpengine/headless-open-source

For the event lifecycle, I have identfied the following events to subscribe to:

Pre-request: do_graphql_request
Building Schema: graphql_register_types
Before Query Execution: pre_graphql_execute_request
Before Field Resolve: graphql_pre_resolve_field
After Field Resolve: graphql_resolve_field
After Query Execution: graphql_execute
Response: graphql_after_execute
Failure: graphql_after_execute

[colinmurphy]

We will also implement a simple pub/sub to subscribe to events

e.g.

add_action('plugins_loaded', static function (): void {
    Plugin::on(Events::PRE_REQUEST, static function(array $payload): void {
        // Do something before a request is executed
    });

    Plugin::on(Events::POST_REQUEST, static function(array $payload): void {
        // Do something after a request finishes
        // error_log('POST_REQUEST: ' . json_encode($payload));
    });
});

[colinmurphy]

Branch - https://github.com/wpengine/hwptoolkit/tree/chore-logging-develop-event-lifecycle

[colinmurphy]

I have refined to log the following events for the initial POC

1. do_graphql_request - Initial GraphQL Request (incoming)
2. graphql_before_execute - Before executing the GraphQL query
3. graphql_execute - After the query execution
4. graphql_return_response - For returning the response or capturing a critical error in the request/response flow.