Overview
The relay API gateway is written in PHP and is based on the API Platform framework as well as the Symfony framework.
To achieve modularity and extensibility we depend on the Symfony bundle system which allows installing "extra parts" to an existing application server, like new API endpoints, new adapters to external systems, and so on.
The following graph shows a more technical overview of how a bundle integrates into the API gateway:
flowchart LR
style ext_service1 fill:#46A046,color:#fff
style ext_service2 fill:#46A046,color:#fff
style oidc_server fill:#C1665A,color:#fff
style client fill:#FFBB00,color:#000
client("Client")
oidc_server("OIDC Server")
subgraph "Relay Gateway"
subgraph api_platform["API Platform / Symfony"]
direction LR
api_docs("API Documentation")
api("REST API")
end
subgraph core_bundle["Core Bundle"]
direction LR
locking("Locking")
message_queue("Message Queue")
authentfication("Authentification")
cron_jobs_management("Cron Jobs")
logging("Logging")
end
end
api_platform <--> core_bundle
subgraph "Extension Bundle"
direction TB
connector_interface("Connector Interface")
subgraph ext_apis["Extensions"]
direction LR
entities("API Resources")
heath_checks("Health Checks")
cron_jobs("Cron Jobs")
async_message("Async Messages")
routes("Symfony Routes")
cli_commands("CLI Commands")
end
ext_apis --> connector_interface
end
subgraph "Connector Bundle"
impl("Implementation")
end
ext_apis --> ext_service2
client --> api_platform
client --> oidc_server
core_bundle <--> ext_apis
core_bundle --> oidc_server
ext_service1("External Service X")
ext_service2("External Service Y")
impl --> ext_service1
connector_interface --> impl
The core bundle provides various common functionality to all bundles and also allows bundles to extend the API gateway in various ways, so they can:
- use the logging system
- use the locking system
- register new API resources and expose the added API in the generated OpenAPI documentation
- register new health checks
- register new cron jobs
- register Symfony messages to be routed to the global worker queue
- register custom Symfony routes for special endpoints that don't fit the api-platform design
- register CLI commands accessible via the Symfony console
Bundle Architecture
See Extending with Bundles for the different types of bundles and their use cases.