cachedb_redis Module

This module is an implementation of a cache system designed to work with a Redis server. It uses hiredis client library to connect to either a single Redis server instance, or to a Redis Server inside a Redis Cluster. It uses the Key-Value interface exported from the core.

1.2. Advantages

memory costs are no longer on the server
many servers can be used inside a cluster, so the memory is virtually unlimited
the cache is 100% persistent. A restart of OpenSIPS server will not affect the DB. The Redis DB is also persistent so it can also be restarted without loss of information.
redis is an open-source project so it can be used to exchange data with various other applications
By creating a Redis Cluster, multiple OpenSIPS instances can easily share key-value information

1.3. Limitations

keys (in key:value pairs) may not contain spaces or control characters

1.4. Dependencies

1.4.1. OpenSIPS Modules

None.

1.4.2. External Libraries or Applications

The following libraries or applications must be installed before running OpenSIPS with this module loaded:

hiredis:
On the latest Debian based distributions, hiredis can be installed by running 'apt-get install libhiredis-dev' Alternatively, if hiredis is not available on your OS repos, hiredis can be downloaded from: https://github.com/antirez/hiredis . Download the archive, extract sources, run make,sudo make install.

1.5. Exported Parameters

1.5.1. `cachedb_url` (string)

The urls of the server groups that OpenSIPS will connect to in order to use the from script cache_store,cache_fetch, etc operations. It can be set more than one time. The prefix part of the URL will be the identifier that will be used from the script.

Example 1.1. Set cachedb_url parameter

...
modparam("cachedb_redis", "cachedb_url","redis:group1://localhost:6379/")
modparam("cachedb_redis", "cachedb_url","redis:cluster1://random_url:8888/")
...

Example 1.2. Use Redis servers

...
cache_store("redis:group1","key","$ru value");
cache_fetch("redis:cluster1","key",$avp(10));
cache_remove("redis:cluster1","key");
...

1.5.2. `connect_timeout` (integer)

This parameter specifies how many milliseconds OpenSIPS should wait for connecting to a Redis node.

Default value is “5000 ms”.

Example 1.3. Set connect_timeout parameter

...
# wait 1 seconds for Redis to connect
modparam("cachedb_redis", "connect_timeout",1000)
...

1.5.3. `query_timeout` (integer)

This parameter specifies how many milliseconds OpenSIPS should wait for a query response from a Redis node.

Default value is “5000 ms”.

Example 1.4. Set connect_timeout parameter

...
# wait 1 seconds for Redis queries
modparam("cachedb_redis", "query_timeout",1000)
...

1.5.4. `shutdown_on_error` (integer)

By setting this parameter to 1, OpenSIPS will abort startup if the initial connection to Redis is not possible. Runtime reconnect behavior is unaffected by this parameter, and is always enabled.

Default value is “0” (disabled).

Example 1.5. Set the shutdown_on_error parameter

...
# abort OpenSIPS startup if Redis is down
modparam("cachedb_redis", "shutdown_on_error", 1)
...

1.6. Exported Functions

The module does not export functions to be used in configuration script.

1.7. Raw Query Syntax

The cachedb_redis module allows to run RAW queries, thus taking full advantage of the capabilities of the back-end. The query syntax is the typical REDIS one.

Here are a couple examples of running some Redis queries :

Example 1.6. Redis Raw Query Examples

...
	$var(my_hash) = "my_hash_name";
	$var(my_key) = "my_key_name";
	$var(my_value) = "my_key_value";
	cache_raw_query("redis","HSET $var(my_hash) $var(my_key) $var(my_value)");
	cache_raw_query("redis","HGET $var(my_hash) $var(my_key)","$avp(result)");
	xlog("We have fetched $avp(result) \n");
...
	$var(my_hash) = "my_hash_name";
	$var(my_key1) = "my_key1_name";
	$var(my_key2) = "my_key2_name";
	$var(my_value1) = "my_key1_value";
	$var(my_value2) = "my_key2_value";
	cache_raw_query("redis","HSET $var(my_hash) $var(my_key1) $var(my_value1)");
	cache_raw_query("redis","HSET $var(my_hash) $var(my_key2) $var(my_value2)");
	cache_raw_query("redis","HGETALL $var(my_hash)","$avp(result)");

	$var(it) = 0;
	while ($(avp(result_final)[$var(it)]) != NULL) {
		xlog("Multiple key reply: - we have fetched $(avp(result_final)[$var(it)]) \n");
		$var(it) = $var(it) + 1;
	}
...

Chapter 2. Contributors

2.1. By Commit Statistics

Table 2.1. Top contributors by DevScore⁽¹⁾, authored commits⁽²⁾ and lines added/removed⁽³⁾

	Name	DevScore	Commits	Lines ++	Lines --
1.	Vlad Paiu (@vladpaiu)	30	17	1428	43
2.	Razvan Crainea (@razvancrainea)	16	13	130	35
3.	Liviu Chircu (@liviuchircu)	12	10	106	55
4.	Bogdan-Andrei Iancu (@bogdan-iancu)	7	5	7	5
5.	jalung	5	1	144	61
6.	Dan Pascu (@danpascu)	3	1	15	15
7.	Ezequiel Lovelle	3	1	11	4
8.	Julián Moreno Patiño	3	1	1	1
9.	Peter Lemenkov (@lemenkov)	3	1	1	1
10.	Jarrod Baumann (@jarrodb)	2	1	12	0

All remaining contributors: Kristian Høgh, Vlad Patrascu (@rvlad-patrascu).

(1) DevScore = author_commits + author_lines_added / (project_lines_added / project_commits) + author_lines_deleted / (project_lines_deleted / project_commits)

(2) including any documentation-related commits, excluding merge commits. Regarding imported patches/code, we do our best to count the work on behalf of the proper owner, as per the "fix_authors" and "mod_renames" arrays in opensips/doc/build-contrib.sh. If you identify any patches/commits which do not get properly attributed to you, please submit a pull request which extends "fix_authors" and/or "mod_renames".

(3) ignoring whitespace edits, renamed files and auto-generated files

2.2. By Commit Activity

Table 2.2. Most recently active contributors⁽¹⁾ to this module

	Name	Commit Activity
1.	Bogdan-Andrei Iancu (@bogdan-iancu)	Oct 2014 - Jun 2020
2.	Liviu Chircu (@liviuchircu)	Mar 2014 - Jan 2020
3.	Razvan Crainea (@razvancrainea)	Feb 2012 - Sep 2019
4.	Dan Pascu (@danpascu)	May 2019 - May 2019
5.	Peter Lemenkov (@lemenkov)	Jun 2018 - Jun 2018
6.	Vlad Patrascu (@rvlad-patrascu)	May 2017 - May 2017
7.	Kristian Høgh	Apr 2016 - Apr 2016
8.	Julián Moreno Patiño	Feb 2016 - Feb 2016
9.	Jarrod Baumann (@jarrodb)	May 2015 - May 2015
10.	jalung	Jun 2014 - Jun 2014

All remaining contributors: Vlad Paiu (@vladpaiu), Ezequiel Lovelle.

(1) including any documentation-related commits, excluding merge commits

Chapter 3. Documentation

3.1. Contributors

Last edited by: Peter Lemenkov (@lemenkov), Liviu Chircu (@liviuchircu), Julián Moreno Patiño, Razvan Crainea (@razvancrainea), Vlad Paiu (@vladpaiu).