67 lines
1.5 KiB
ReStructuredText
67 lines
1.5 KiB
ReStructuredText
Request Life Cycle
|
|
==================
|
|
|
|
This section describes the sequence of events happening for each request
|
|
answered by the `HTTP User Interface`.
|
|
|
|
.. image:: ../_static/request_life_cycle.png
|
|
|
|
|
|
1. request
|
|
----------
|
|
|
|
The user makes a request to the `HTTP User Interface`.
|
|
|
|
- The request is matched against the route table.
|
|
|
|
- :program:`kapow` provides a `HANDLER_ID` to identify this request and don't
|
|
mix it with other requests that could be running concurrently.
|
|
|
|
|
|
2. spawn
|
|
--------
|
|
|
|
:program:`kapow` spawns the executable specified as entrypoint in the matching
|
|
route.
|
|
|
|
The default entrypoint is ``/bin/sh``; let's focus on this workflow.
|
|
|
|
The spawned entrypoint is run with the following variables added to its
|
|
environment:
|
|
|
|
- :envvar:`KAPOW_HANDLER_ID`: Containing the `HANDLER_ID`
|
|
- :envvar:`KAPOW_DATAAPI_URL`: With the URL of the `HTTP Data Interface`
|
|
- :envvar:`KAPOW_CONTROLAPI_URL`: With the URL of the `HTTP Control Interface`
|
|
|
|
|
|
3. ``kapow set /response/body banana``
|
|
--------------------------------------
|
|
|
|
During the lifetime of the shell, the request and response resources are
|
|
available via these commands:
|
|
|
|
- ``kapow get /request/...``
|
|
|
|
- ``kapow set /response/...``
|
|
|
|
These commands use the aforementioned environment variables to read data
|
|
from the user request and to write the response. They accept data either as
|
|
arguments or from `stdin`.
|
|
|
|
|
|
4. exit
|
|
-------
|
|
|
|
The shell dies. Long live the shell!
|
|
|
|
|
|
5. response
|
|
-----------
|
|
|
|
:program:`kapow` finalizes the original request. Enjoy your banana now.
|
|
|
|
|
|
.. todo::
|
|
|
|
link to resource tree
|