[SR-Users] Invoking RPC commands over HTTP

[Ben Hood]

Hi Aleksandar,

That's quite a cool set of technologies that you've integrated together :-)

Many thanks for taking the time to explain this so clearly, very much
appreciated.

I like the fact that you've connected a GraphQL query (which I've only
really seen being used in React) to populate a tmp file.

Previously I had never thought of doing redirecting printf to a well
known file (shared memory in one sense), but it seems like a simple
and effective thing to do, especially as the data in that file is
inherently reconstructable via a remote request.

It also demonstrates the use of jsonrpc_exec - this command is
invoking a local RPC API without a network call.

Many thanks,

Ben

On Fri, Mar 2, 2018 at 10:03 PM, Aleksandar Sosic <alex.sosic at timenet.it> wrote:
> Hi Ben,
>
> we are working on a dockerized infrastructure orchestrated with
> Kubernetes with two kamailio layers, a `proxy` and a `router` level.
> In a stateless infrastructure like that we need to have also a SIP
> orchestrator that will handle all the active and ready nodes and
> notify or provide the correct information to all the other nodes upon
> changes in the infrastructure.
>
> So upon the creation of a `router` node we will give it a list of
> `proxy` nodes (Kamailio), `TPS` (transcoding and playback handled by
> asterisk), `RTPs` (rtpengine). When that container (aka Pod in
> kubernetes) starts and it's ready we also notify the `proxy` nodes to
> reload the dispatcher list and add the new node. We do that via API.
>
> The API is a Node.js application using GraphQL query language. So our
> DISPATCHER_LIST route does an async http request to the API:
> ```
> route[DISPATCHER_LIST] {
>   if($sht(api=>token) == $null) {
>     route(GET_API_TOKEN);
>   }
>   $http_req(method) = "POST";
>   $http_req(hdr) = "Content-Type: application/json";
>   $http_req(hdr) = "Authorization: Bearer " + $sht(api=>token);
>   $var(graphql_query) = "{\"query\": \"{ kamailio { dispatcher { list
> { kamailioConf } } } }\"}";
>   $http_req(body) = $var(graphql_query);
>   http_async_query(API_QUERY_URL, "DISPATCHER_SET");
> }
> ```
>
> We're using the JWT as authentication/security between nodes and API.
>
> the DISPATCHER_SET route then handles the async response:
> ```
> route[DISPATCHER_SET] {
>   jansson_get("data.kamailio.dispatcher.list.kamailioConf", $http_rb,
> "$var(api_conf)");
>   if($var(api_conf) != "0") {
>     exec_msg("printf \"$var(api_conf)\" > /tmp/dispatcher.list");
>     jsonrpc_exec('{"jsonrpc": "2.0", "method": "dispatcher.reload",
> "id": "1"}');
> ...
> }
> ```
>
> Those are simplified routes without logs and checks and failovers.
> As you can immagine the dispatcher module has a param like this:
> ```
> modparam("dispatcher", "list_file", "/tmp/dispatcher.list")
> ```
>
> I'll be giving a speech on CD/CI and Kamailio route testing in a
> dockerized environment like this at this year Kamailio World
> Conference in Berlin:
> https://www.kamailioworld.com/k06/speakers/
>
> If you're attending the event we can discuss this further ad visum.
>
> Kind regards,
> --
> Aleksandar Sosic
> mail: alex.sosic at timenet.it
> skype: alex.sosic
> cell: +385 91 2505 146
>
>
> On Fri, Mar 2, 2018 at 6:46 PM, Ben Hood <0x6e6562 at gmail.com> wrote:
>> Hey Aleksandar,
>>
>> Many thanks for the heads up - very interesting to see how other
>> people are doing this.
>>
>> So if I understand you correctly, you have a dynamic list of dispatchers.
>>
>> And then you invoke "dispatcher.reload" to reload all of the
>> dispatchers you have defined dynamically?
>>
>> What does the  DISPATCHER_LIST route look like?
>>
>> Cheers,
>> Ben
>>
>>
>> On Fri, Mar 2, 2018 at 9:29 AM, Aleksandar Sosic <alex.sosic at timenet.it> wrote:
>>> Hi Ben,
>>>
>>> we're using something like this to do dispatcher.reload:
>>>
>>> ```
>>> event_route[xhttp:request] {
>>> if ($hu =~ "^/rpc") {
>>> $var(command) = $(hu{s.select,2,/});
>>> $var(parameter) = $(hu{s.select,3,/});
>>>
>>> if($var(command) == "reload.dispatchers") {
>>> route(DISPATCHER_LIST);
>>> xhttp_reply("200", "OK", "text/html", "Dispatchers Set for RELOAD");
>>> exit;
>>> }
>>> ...
>>> }
>>> ```
>>>
>>> And then in the DISPATCHER_LIST route we do an API call for fetching
>>> the updated dispatcher list for that node.
>>> After the dispatcher list is updated we just run:
>>> jsonrpc_exec('{"jsonrpc": "2.0", "method": "dispatcher.reload", "id": "1"}');
>>>
>>> So you can just put a `jsonrpc_exec` inside the event_route[xhttp:request].
>>
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