EVAPI Module

Daniel-Constantin Mierla

   <miconda@gmail.com>

Edited by

Daniel-Constantin Mierla

   <miconda@gmail.com>

   Copyright © 2014 asipto.com
     __________________________________________________________________

   Table of Contents

   1. Admin Guide

        1. Overview
        2. Dependencies

              2.1. Kamailio Modules
              2.2. External Libraries or Applications

        3. Parameters

              3.1. workers (int)
              3.2. bind_addr (str)
              3.3. netstring_format (int)
              3.4. event_callback (str)
              3.5. max_clients (int)

        4. Functions

              4.1. evapi_relay(evdata)
              4.2. evapi_async_relay(evdata)
              4.3. evapi_multicast(evdata, etag)
              4.4. evapi_async_multicast(evdata, etag)
              4.5. evapi_unicast(evdata, etag)
              4.6. evapi_async_unicast(evdata, etag)
              4.7. evapi_close()
              4.8. evapi_set_tag(tname)

        5. Event routes

              5.1. evapi:connection-new
              5.2. evapi:connection-closed
              5.3. evapi:message-received

        6. Exported pseudo-variables

   List of Examples

   1.1. Set workers parameter
   1.2. Set bind_addr parameter
   1.3. Set netstring_format parameter
   1.4. Set event_callback parameter
   1.5. Set max_clients parameter
   1.6. evapi_relay usage
   1.7. TCP message
   1.8. evapi_async_relay usage
   1.9. evapi_multicast usage
   1.10. evapi_async_multicast usage
   1.11. evapi_unicast usage
   1.12. evapi_async_unicast usage
   1.13. evapi_close usage
   1.14. evapi_set_tag usage

Chapter 1. Admin Guide

   Table of Contents

   1. Overview
   2. Dependencies

        2.1. Kamailio Modules
        2.2. External Libraries or Applications

   3. Parameters

        3.1. workers (int)
        3.2. bind_addr (str)
        3.3. netstring_format (int)
        3.4. event_callback (str)
        3.5. max_clients (int)

   4. Functions

        4.1. evapi_relay(evdata)
        4.2. evapi_async_relay(evdata)
        4.3. evapi_multicast(evdata, etag)
        4.4. evapi_async_multicast(evdata, etag)
        4.5. evapi_unicast(evdata, etag)
        4.6. evapi_async_unicast(evdata, etag)
        4.7. evapi_close()
        4.8. evapi_set_tag(tname)

   5. Event routes

        5.1. evapi:connection-new
        5.2. evapi:connection-closed
        5.3. evapi:message-received

   6. Exported pseudo-variables

1. Overview

   The EVAPI module can be used to create an event message flow from
   Kamailio to any application that can connect to a TCP socket. The
   remote application can also issue messages received by Kamailio.

   There is no protocol definition, it is all up to the author of the
   routing script. Events can be generated for any event in Kamailio. For
   3rd party transaction control, a transaction can be automatically
   suspended when sending the event, to be resumed at a later point, maybe
   triggered by an incoming message on the event socket.

2. Dependencies

   2.1. Kamailio Modules
   2.2. External Libraries or Applications

2.1. Kamailio Modules

   The following modules must be loaded before this module:
     * tm - (optional) needed only by evapi_async_relay()

2.2. External Libraries or Applications

   The following libraries or applications must be installed before
   running Kamailio with this module loaded:
     * libev - http://software.schmorp.de/pkg/libev

3. Parameters

   3.1. workers (int)
   3.2. bind_addr (str)
   3.3. netstring_format (int)
   3.4. event_callback (str)
   3.5. max_clients (int)

3.1. workers (int)

   Number of worker processes to be started to handle incoming messages
   from remote applications.

   Default value is 1.

   Example 1.1. Set workers parameter
...
modparam("evapi", "workers", 2)
...

3.2. bind_addr (str)

   Local IP and port to listen on for incoming TCP connections.

   Default value is "127.0.0.1:8448".

   Example 1.2. Set bind_addr parameter
...
modparam("evapi", "bind_addr", "1.2.3.4:8228")
...

3.3. netstring_format (int)

   Control if messages on the socket (to and from clients) are
   encapsulated in netstring format.

   Default value is 1 (netstring format).

   Example 1.3. Set netstring_format parameter
...
modparam("evapi", "netstring_format", 0)
...

3.4. event_callback (str)

   The name of the function in the kemi configuration file (embedded
   scripting language such as Lua, Python, ...) to be executed instead of
   event_route[...] blocks.

   The function receives a string parameter with the name of the event,
   the values are: 'evapi:connection-new', 'evapi:connection-closed',
   'evapi:message-received'.

   Default value is 'empty' (no function is executed for events).

   Example 1.4. Set event_callback parameter
...
modparam("evapi", "event_callback", "ksr_evapi_event")
...
-- event callback function implemented in Lua
function ksr_evapi_event(evname)
        KSR.info("===== evapi module triggered event: " .. evname .. "\n");
        return 1;
end
...

3.5. max_clients (int)

   Maximum number of clients that can connect to evapi socket.

   Default value is 8.

   Example 1.5. Set max_clients parameter
...
modparam("evapi", "max_clients", 4)
...

4. Functions

   4.1. evapi_relay(evdata)
   4.2. evapi_async_relay(evdata)
   4.3. evapi_multicast(evdata, etag)
   4.4. evapi_async_multicast(evdata, etag)
   4.5. evapi_unicast(evdata, etag)
   4.6. evapi_async_unicast(evdata, etag)
   4.7. evapi_close()
   4.8. evapi_set_tag(tname)

4.1.  evapi_relay(evdata)

   Relay the event data given as parameter to connected applications.

   The format on the network is netstring with evdata payload if
   netstring_format parameter is set to 1 or bare evdata if
   netstring_format parameter is set to 0.

   The function is passing the task to evapi dispatcher process, therefore
   the SIP worker process is not blocked. Also, it doesn't wait for any
   response, therefore the processing of the configuration continues very
   fast when executing evapi_relay().

   This function can be used from ANY_ROUTE.

   Example 1.6. evapi_relay usage
...
evapi_relay("{ \"event\": \"test\",\n \"data\": { \"fU\": \"$fU\" }\n}");
...

   The above exaple will send the following message over tcp:

   Example 1.7. TCP message
...
47:{
 "event": "test",
 "data": { "fU": "test" }
},
...

4.2.  evapi_async_relay(evdata)

   Relay the event data given as parameter to connected applications.
   Before evaluating the parameter, the request processing is suspended
   using tm module (using the t_suspend()/t_continue() framework). The
   routing of the SIP request can be continued once
   event_route[evapi:message-received] is triggered. After
   evapi_async_relay() returns true, no relaying should happen in
   request_route(), it should be followed by exit;.

   The format on the network is netstring with evdata payload if
   netstring_format parameter is set to 1 or bare evdata if
   netstring_format parameter is set to 0.

   This function can be used from REQUEST_ROUTE.

   Example 1.8. evapi_async_relay usage
...
evapi_async_relay("{ \"event\": \"suspend\",\n \"data\":"
        " { \"index\": \"$T(id_index)\", \"label\": \"$T(id_label)\" }\n}");
...

4.3.  evapi_multicast(evdata, etag)

   Relay the event data given as parameter to connections that match the
   tag provided by etag value. The etag can be a variable. For more see
   evapi_relay() and evapi_set_tag().

   Example 1.9. evapi_multicast usage
...
evapi_multicast("{ \"event\": \"test\",\n \"data\": { \"fU\": \"$fU\" }\n}", "ta
gx");
...

4.4.  evapi_async_multicast(evdata, etag)

   Async relay the event data given as parameter to connections that match
   the tag provided by etag value. The etag can be a variable. For more
   see evapi_async_relay() and evapi_set_tag().

   Example 1.10. evapi_async_multicast usage
...
evapi_async_multicast("{ \"event\": \"suspend\",\n \"data\":"
    " { \"index\": \"$T(id_index)\", \"label\": \"$T(id_label)\" }\n}", "tagx");
...

4.5.  evapi_unicast(evdata, etag)

   Relay the event data given as parameter to the first connection that
   match the tag provided by etag value. The etag can be a variable. For
   more see evapi_relay() and evapi_set_tag().

   Example 1.11. evapi_unicast usage
...
evapi_unicast("{ \"event\": \"test\",\n \"data\": { \"fU\": \"$fU\" }\n}", "tagx
");
...

4.6.  evapi_async_unicast(evdata, etag)

   Async relay the event data given as parameter to the first connection
   that match the tag provided by etag value. The etag can be a variable.
   For more see evapi_async_relay() and evapi_set_tag().

   Example 1.12. evapi_async_unicast usage
...
evapi_async_unicast("{ \"event\": \"suspend\",\n \"data\":"
    " { \"index\": \"$T(id_index)\", \"label\": \"$T(id_label)\" }\n}", "tagx");
...

4.7.  evapi_close()

   Close evapi current client connection.

   This function can be used from ANY_ROUTE.

   Example 1.13. evapi_close usage
...
event_route[evapi:connection-new] {
  if($evapi(srcaddr)!="127.0.0.1") {
    evapi_close();
    exit;
  }
}
...

4.8.  evapi_set_tag(tname)

   Set tag name for current client connection. The parameters has to be a
   string up to 64 characters. It can also be a variable holding such
   string.

   This function can be used from ANY_ROUTE.

   Example 1.14. evapi_set_tag usage
...
event_route[evapi:connection-new] {
  if($evapi(srcaddr)=="127.0.0.1") {
    evapi_set_tag("local");
    exit;
  }
}
...

5. Event routes

   5.1. evapi:connection-new
   5.2. evapi:connection-closed
   5.3. evapi:message-received

5.1.  evapi:connection-new

   If defined, the module calls event_route[evapi:connection-new] when a
   new client is connected.
...
event_route[evapi:connection-new] {
    xlog("new connection from $evapi(srcaddr):$evapi(srcport)\n");
}
...

5.2.  evapi:connection-closed

   If defined, the module calls event_route[evapi:connection-closed] when
   a client connection is closed.
...
event_route[evapi:connection-closed] {
    xlog("connection closed by $evapi(srcaddr):$evapi(srcport)\n");
}
...

5.3.  evapi:message-received

   If defined, the module calls event_route[evapi:message-received] when a
   message is received from a client.
...
event_route[evapi:message-received] {
    xlog("received [$evapi(msg)] from $evapi(srcaddr):$evapi(srcport)\n");
}
...

6. Exported pseudo-variables

     * $evapi(srcaddr) - source ip
     * $evapi(srcport) - source port
     * $evapi(msg) - received event message
     * $evapi(conidx) - internal connection index

   Exported pseudo-variables are documented at
   https://www.kamailio.org/wiki/.
