Kazoo configuration, for the most part, lives in the system_config database (with a few exceptions for BigCouch, RabbitMQ, and basic Kazoo settings).

The sysconf app provides an AMQP listener for requests to manipulate values from the system_config database without needing to interact with the database directly.

AMQP API

Get system config values

To fetch a value, publish a get_req to the sysconf AMQP exchange using "sysconf.get" as the routing key. The payload to publish:

• Event-Category: "sysconf"
• Event-Name: "get_req"
• Category: The name of the system_config document (eg "ecallmgr", "kapps_controller", etc)
• Key: The key of the value desired (eg "fs_nodes")
• Default: (optional) If no Key is found, return this value as the result (will also set Default in the config document
• Node: The node to select the config from ("default" or "[email protected]")
• Server-ID: The AMQP queue, bound to the targeted exchange, to send the reply.
• Msg-ID: Unique identifier for this request

The Response

The response will be published to the targeted AMQP exchange, using the Server-ID as the routing key. The payload published will be:

• Event-Category: "sysconf"
• Event-Name: "get_resp"
• Category: The category retrieved
• Key: The key retrieved
• Value: The value retrieved
• Msg-ID: The request's Msg-ID

Building ACLs

Most of the time, requests will simply read the value from the system_config document. ACL generation is a special case, as Kazoo needs to fetch data from the sip_auth database, where local resources (per-account carriers) and auth-by-ip devices live.

The sysconf_acls module implements a scatter-gather approach:

1. The requesting PID spawns three processes:
   1. Process the sip_auth database's auth-by-ip docs
   2. Process the offnet database's (or global resources) docs
   3. Process the sip_auth database's local resources (account carriers)
2. Fetches the ecallmgr ACL list from system_config
3. Receives 0 or more messages from the spawned processes (or their children processes) with additional ACLs to add
4. After all three child processes have finished (or the request times out), the collected ACLs are returned to the requestor.

Within the three sub processes, each will search for IPs and hostnames. If a hostname is encountered, attempts will be made to resolve the hostname into IP(s). These resolved hostnames and raw IPs will then create an ACL entry and communicate that back to the requesting PID (the Collector in the code).

Set system config values

To set a value in a particular config doc, publish a set_req to the sysconf AMQP exchange using "sysconf.set" as the routing key. The payload to publish:

• Event-Category: "sysconf"
• Event-Name: "set_req"
• Category: The name of the system_config document (eg "ecallmgr", "kapps_controller", etc)
• Key: The key to set
• Value: The value to set
• Node-Specific: (optional) Set as the "default" config or as a node's specific config ('false' by default - will set in the "default" config)
• Node: If Node-Specific is "true", use this value as the top-level key into the system_config's Category document.
• Server-ID: The AMQP queue, bound to the targeted exchange, to send the reply.

The Response

The response will be published to the targeted AMQP exchange, using the Server-ID as the routing key. The payload published will be:

• Event-Category: "sysconf"
• Event-Name: "set_resp"
• Category: The category being updated
• Key: The key being updated
• Value: The value set
• Msg-ID: The request's Msg-ID

Flushing values

Sometimes a change will be made to a document in system_config directly in the database. Because Kazoo caches the config documents when they're fetched, it may be necessary to flush a given Category doc from the Kazoo cache. Publish a flish_req to the sysconf AMQP exchange using "sysconf.flush" as the routing key. The payload to publish:

• Event-Category: "sysconf"
• Event-Name: "flush_req"
• Category: The name of the system_config document (eg "ecallmgr", "kapps_controller", etc)
• Key: (optional) Flush only this key's value from the cached doc