func_redis

func_redis is a asterisk module to use Redis from the dialplan. It uses hiredis as library for redis. I have tested it in Asterisk 11.6 certified version and asterisk 13.9.

Motivation of the project

This project is motivated by the need to share information between different asterisk in both active-active and active-passive scheme.

In the case of passive-active scheme if you use AstDB for storing data, when system switch over, the data in AstDB isn't in the passive node, so some functionality is lost, using Redis instead of AstDB, the active node and the passive one can access the data, even the possibility of making an passive active redis scheme in this case the active asterisk attack the active redis and the passive asterisk attacks the passive redis with this scheme you can have on the same machine redis and Asterisk.

In the case of both active-active scheme asterisk can share information easily by redis.

func_redis is not a drop in replacement of AstDB, internally asterisk uses AstDB, for example to keep registry of the phones.

You can use an agi script or a system call to a script to use redis from the dialplan but the performance is low compared to a asterisk module and the integration is worst.

Dependencies

• gcc

  • [Ubuntu] apt-get install build-essential
  • [Archlinux] pacman -S gcc

• cmake

  • [Ubuntu] apt-get install cmake
  • [Archlinux] pacman -S cmake

• redis

  • [Ubuntu] apt-get install redis-server
  • [Archlinux] pacman -S redis

• hiredis

  • [Ubuntu] apt-get install libhiredis-dev
  • [Archlinux] pacman -S hiredis

• asterisk

  • [Ubuntu] apt-get install asterisk asterisk-dev
  • [Archlinux] pacman -S asterisk

Instalation

1. Install the dependencies
2. mkdir build
3. cd build
4. cmake -DCMAKE_BUILD_TYPE=Release ..
5. make
6. make install
7. make samples
8. make doc

Uninstall

• make unistall

Using func_redis

In order to use the func_redis you have to configure the settings for the module in the file func_redis.conf. There is an example in samples/func_redis.conf.sample, if you run make samples it will copy this file to /etc/asterisk

Here an example of the file :

[general]
; host of the redis server
; if not defined, use default of 127.0.0.1
hostname=127.0.0.1

; port of the redis server
; if not defined, use default of 6379
port=6379

; database index in redis
; if not defined, use default of 0
database=0

; password for redis server
; if not defined, authentication will not be used
;password=s3cr3tp@ssw0rd

; connection time out when connecting to the server
; if not defined, use a default of 5 seconds
timeout=3

; send a BGSAVE on connection close/module unload
; if not defined, use a default of false
bgsave=false

Using func_redis from the Dialplan

Func redis have two apis one similar to AstDB and another generic, if you don't want to learn how redis work use the AstDB API but if you know how redis work you can use the generic API that is more powerful. All the redis dialplan functions saves its results in REDIS_RESULT it is a string always, if the response is an redis array it puts the elements in a coma separated way like value1,value2,value3 , if the result is a redis nil the REDIS_RESULT is equal to "nil". If there was errors the channel variable REDIS_ERROR is filled with the error.

AstDB API

Set a key value

same => n,Set(REDIS(key)=${VALUE})

Get the value from a key

same => n,Set(VALUE=${REDIS(key)})

Delete a key

same => n,NoOp(Deleting test key ${REDIS_DELETE(key)})

Check if a key exists

same => n,GotoIf(${REDIS_EXISTS(key)}?exists:doesnt_exist)

Generic API

Every redis comand

same => n,NoOp(REDIS_COMMAND(PUBLISH channel message))
same => n,NoOp(REDIS_COMMAND(MGET key1 key2 key3))
same => n,NoOp(REDIS_COMMAND(LPOP alist))

Using func_redis from the CLI

You can use these commands related to func_redis in the Asterisk CLI

1. redis show [pattern] Shows all the key values. [pattern] pattern to match keys Examples : - h?llo matches hello, hallo and hxllo - h*llo matches hllo and heeeello - h[ae]llo matches hello and hallo, but not hillo

2. redis set <key> <value> Sets the key's value to .

3. redis del <key> Deletes the key-value pair in redis.

Develop environment

Start Developing

This repo have a Vagrantfile with the needed configuration to have a functional yet basic development environment. To use it you should run

vagrant up
vagrant ssh

You can find the project in the vm in the folder /func_redis. You can make the changes that you wish and then

mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Debug ..
make
make install

Testing the module

I don't use a proper test suite but in exchange I test the module making use of the dialplan, call files and local channels, to run the test

make dialplan_test

Code security and tools

To check if the code uses insecure functions and make some security checks run

make security_checks

for security checks it uses the nexts static analyzers :

• cppcheck
• graudit
• flawfinder

Contribute and collaborate

See CONTRIBUTING.md