diff --git a/docs/source/index.rst b/docs/source/index.rst index cd47276..21290ba 100644 --- a/docs/source/index.rst +++ b/docs/source/index.rst @@ -20,6 +20,7 @@ theory/philosophy theory/request_life_cycle theory/resource_tree + theory/routes diff --git a/docs/source/theory/route_matching.rst b/docs/source/theory/route_matching.rst new file mode 100644 index 0000000..31d58bd --- /dev/null +++ b/docs/source/theory/route_matching.rst @@ -0,0 +1,12 @@ +Route Matching +============== + +Route table +----------- + + Kapow! maintains a route table as provided by the user, and uses it to determine + which handler should an incoming request be dispatched to. + + Each incoming request is matched against the routes in the route table in + strict order, for each route in the route table, the criteria are checked. + If the request does not match, the next route in the route list is examined. diff --git a/docs/source/theory/routes.rst b/docs/source/theory/routes.rst new file mode 100644 index 0000000..d262ffd --- /dev/null +++ b/docs/source/theory/routes.rst @@ -0,0 +1,124 @@ +Routes +====== + +A Kapow! route specifies the matching criteria for an incoming request on +the `User HTTP Interface`, and the details to handle it. + +Kapow! implements a *route table* where all routes reside. + + +A route can be set like this: + +.. code-block:: bash + + $ kapow route add \ + -X POST \ + '/register/{username}' \ + -e '/bin/bash -c' \ + -c 'touch /var/lib/mydb/"$(kapow get /request/matches/username)"' \ + | jq + { + "id": "deadbeef-0d09-11ea-b18e-106530610c4d", + "method": "POST", + "url_pattern": "/register/{username}", + "entrypoint": "/bin/bash -c", + "command": "touch /var/lib/mydb/\"$(kapow get /request/matches/username)\"" + } + +Let's use this example to discuss its elements. + + +Elements +-------- + +``id`` Route Element +~~~~~~~~~~~~~~~~~~~~ + +Uniquely identifies each route. It is used for instance by ``kapow route remove +``. + +.. note:: + + The current implementation of Kapow! autogenerates a `UUID` for this field. + In the future the use will be able to specify a custom value. + + +``method`` Route Element +~~~~~~~~~~~~~~~~~~~~~~~~ + +Specifies the HTTP method for the route to match the incoming request. + +The route shown above will only match a ``POST`` request. + + +``url_pattern`` Route Element +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +It matches the `path` component of the `URL` of the incoming request. + +It can contain regex placeholders for easily capturing fragments of the path. + +In the route shown above, a request with a URL ``/register/joe`` would match, +assigning `joe` to the placeholder ``username``. + +Kapow! leverages Gorilla Mux for managing routes. For the full story, see +https://github.com/gorilla/mux#examples + + +``entrypoint`` Route Element +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +This sets the executable to be spawned, along with any arguments required. + +In the route shown above, the entrypoint that will be run is ``/bin/bash -c``, +which is an incomplete recipe. It is completed by the `command` element. + +.. todo:: + + link to command below + + +.. note:: + + The semantics of this element closely match `Docker`'s ``ENTRYPOINT`` directive. + +.. todo:: + + link to Docker docu + + +``command`` Route Element +~~~~~~~~~~~~~~~~~~~~~~~~~ + +This is an optional last argument to be passed to the ``entrypoint``. + +In the route shown above, it completes the `entrypoint` to form the final +incantation to be executed: + +.. todo:: + + link to entrypoint above + +.. code-block:: + + /bin/bash -c 'touch /var/lib/mydb/"$(kapow get /request/matches/username)"' + +.. note:: + + The semantics of this element closely match `Docker`'s ``COMMAND`` directive. + +.. todo:: + + link to Docker docu + + +Matching Algorithm +------------------ + +`Kapow!` leverages Gorilla Mux for this task. You can see the gory details in +their documentation. + + +.. todo:: + + link to Gorilla Mux docu