Publishing processes via OGC API - Processes¶

OGC API - Processes provides geospatial data processing functionality in a standards-based fashion (inputs, outputs).

pygeoapi implements OGC API - Processes functionality by providing a plugin architecture, thereby allowing developers to implement custom processing workflows in Python.

A sample hello-world process is provided with the pygeoapi default configuration.

Configuration¶

processes:
    hello-world:
        processor:
            name: HelloWorld

Asynchronous support¶

By default, pygeoapi implements process execution (jobs) as synchronous mode. That is, when jobs are submitted, the process is executed and returned in real-time. Certain processes that may take time to execute, or be delegated to a scheduler/queue, are better suited to an asynchronous design pattern. This means that when a job is submitted in asynchronous mode, the server responds immediately with a reference to the job, which allows the client to periodically poll the server for the processing status of a given job.

pygeoapi provides asynchronous support by providing a ‘manager’ concept which, well, manages job execution. The manager concept is implemented as part of the pygeoapi Customizing pygeoapi: plugins architecture. pygeoapi provides a default manager implementation based on TinyDB for simplicity. Custom manager plugins can be developed for more advanced job management capabilities (e.g. Kubernetes, databases, etc.).

server:
    manager:
        name: TinyDB
        connection: /tmp/pygeoapi-process-manager.db
        output_dir: /tmp/

Putting it all together¶

To summarize how pygeoapi processes and managers work together:

- process plugins implement the core processing / workflow functionality
- manager plugins control and manage how processes are executed

Processing examples¶

list all processes - http://localhost:5000/processes
describe the hello-world process - http://localhost:5000/processes/hello-world
show all jobs for the hello-world process - http://localhost:5000/processes/hello-world/jobs
execute a job for the hello-world process - curl -X POST "http://localhost:5000/processes/hello-world/jobs" -H "Content-Type: application/json" -d "{\"inputs\":[{\"id\":\"name\",\"type\":\"text/plain\",\"value\":\"hi there2\"}]}"
execute a job for the hello-world process with a raw response - curl -X POST "http://localhost:5000/processes/hello-world/jobs?response=raw" -H "Content-Type: application/json" -d "{\"inputs\":[{\"id\":\"name\",\"type\":\"text/plain\",\"value\":\"hi there2\"}]}"
execute a job for the hello-world process in asynchronous mode - curl -X POST "http://localhost:5000/processes/hello-world/jobs" -H "Content-Type: application/json" -d "{\"mode\": \"async\", \"inputs\":[{\"id\":\"name\",\"type\":\"text/plain\",\"value\":\"hi there2\"}]}"

Todo

add more examples once OAProc implementation is complete