FusionPBX/FreeSWITCH save CLID on transfer

Idea is when call is received, transfer to next destination should come with callerID was received originally, not updated in moment of transfer. Sometimes it's needed for correct CRM integration or peoples just get used to it, cause it's default with blind transfer.

Actually, same ideas that described here, but for use in FusionPBX.

1. Create context save_transfer with order ~85
condition - <empty>
action - export - nolocal:execute_on_answer_1=lua number_save_on_transfer_store.lua
action - export - api_hangup_hook=lua number_save_on_transfer_db_cleanup.lua

2. Create context restore_transfer with order higher, than save_trasfer, ~80
condition - ${db(exists/number_transfer_store/${sip_from_user})} - ^true$
action - set - restored_number_on_transfer=${db(select/number_transfer_store/${sip_from_user})} - inline
action - set - effective_caller_id_number=${restored_number_on_transfer}
action - set - effective_caller_id_name=${restored_number_on_transfer}
action - db - delete/number_transfer_store/${sip_from_user}
condition - ${db(exists/number_transfer_store/${sip_from_user}_name)} - ^true$
action - set - restored_number_on_transfer_name=${db(select/number_transfer_store/${sip_from_user}_name)} - inline
action - set  - effective_caller_id_name=${restored_number_on_transfer_name}
action - db - delete/number_transfer_store/${sip_from_user}_name

Lua files:
/usr/share/freeswitch/scripts/number_save_on_transfer_store.lua

-- Save number_answered / original caller_id to database

--api = freeswitch.API()

if (session:ready()) then
    answered_extension = session:getVariable("dialed_user")

    caller_id = session:getVariable("restored_number_on_transfer")
    caller_name = session:getVariable("restored_number_on_transfer_name")

    if (caller_id == nil) then
        caller_id = session:getVariable("sip_from_user")
    end
    if (caller_name == nil) then
        caller_name = session:getVariable("sip_from_display")
    end
    if (answered_extension ~= nil and caller_id ~= nil) then
        freeswitch.consoleLog("INFO", "[NUMBER_ON_TRANSFER_SAVE] Got answered call from "..caller_id.." to "..answered_extension.."\n")
        session:execute('db', 'insert/number_transfer_store/'..answered_extension..'/'..caller_id)
        if (caller_name ~= nil) then
            session:execute('db', 'insert/number_transfer_store/'..answered_extension..'_name/'..caller_name)
        end
    end
end

/usr/share/freeswitch/scripts/number_save_on_transfer_db_cleanup.lua

-- Cleanup database

api = freeswitch.API()
sip_to_user = env:getHeader("variable_last_sent_callee_id_number")

if (sip_to_user ~= nil) then
--serialized = env:serialize()
--freeswitch.consoleLog("INFO","[hangup]\n" .. serialized .. "\n")

    freeswitch.consoleLog("INFO", "[DB_CLEANUP] Cleaning " .. sip_to_user .. "\n")
    api:executeString('db delete/number_transfer_store/'..sip_to_user)
    api:executeString('db delete/number_transfer_store/'..sip_to_user..'_name')
end



P.S.: At the end, db is can be easily replaced with hash. As we don't need persistence storage here.

Freeswitch/Fusion stop/resume record on the fly

Most common solution to pause/resume recording on Freeswitch is use stop_record_session and after - record_session along with RECORD_APPEND=true.
What is bad with this solution.
1. Only WAV is supported
2. Seems it's broken for now (1.6.18)
Other option to use is
uuid_record mask/unmask

For FusionPBX it will looks like
action - bind_digit_action - local,*1,api:uuid_record,${uuid} mask ${recordings_dir}/${domain_name}/archive/${strftime(%Y)}/${strftime(%b)}/${strftime(%d)}/${uuid}.${record_ext},${bind_target}

action - bind_digit_action - local,*2,api:uuid_record,${uuid} unmask ${recordings_dir}/${domain_name}/archive/${strftime(%Y)}/${strftime(%b)}/${strftime(%d)}/${uuid}.${record_ext},${bind_target}

So, you may press *1 to stop recording and *2 to resume it. Bad in this solution - you will have pauses in conversation while record is masked.

Freeswitch Postgres database scheme

Freeswitch has a great option to put internal database from SQL to Postgres. But in a case if Postgres DB is BDR (as I've described here), there is need some additional work on this database.

So, I've created SQL file to use, based on DigiDaz file. 

You can find it here. Don't forget to set

<param name="auto-create-schemas" value="false"/>

<param name="auto-clear-sql" value="false"/>

in your switch.comf.xml file.

Also few things about BDR. You can't add primary key to existing database in one command. But you can use thing like:

ALTER TABLE tbl ADD COLUMN tbl_uuid uuid;

ALTER TABLE tbl ALTER COLUMN tbl_uuid  SET DEFAULT  gen_random_uuid();

ALTER TABLE tbl ADD PRIMARY KEY (tbl_uuid);

Fax in FreeSwitch

Just a link not to forget where to get variables related to faxing in FreeSwitch

Examples in source
And explanations on Youtube

Kamailio limit CPS/CPM/Concurrent calls per gateway.

Small task to make some generic limiters for calls per gateway, which in my case - destination.
Limiting concurrent calls is based on dialog module, limiting CPS/CPM - on htable module, actual solution taken from here.

On a modparam I'm pointing only on settings, that needed for this solution, so, if you want to adopt it to your case - use your settings along with provided.

loadmodule "htable.so"
...
modparam("htable", "htable", "rhs=>size=32;initval=0;autoexpire=300;")
modparam("htable", "htable", "rhm=>size=32;initval=0;autoexpire=1800;")

loadmodule "dialog.so"
...
modparam("dialog", "profiles_with_value", "concurrent_calls")

...

request_route {

...

   if (is_method("INVITE")) {

      route(LIMIT_CALLS)

   }

...

}

route[LIMIT_CALLS] {
    # Limit oncurrent calls per gateway
    if (!dlg_isflagset("1")) {
        if (get_profile_size("concurrent_calls", "$td", "$avp(calls)")) {
            $avp(concCallLimit) = <ACTUAL_CONCURRENT_CALLS_LIMIT_HERE>;
            if ($avp(calls) >= $avp(concCallLimit)) {
                xlog("L_INFO", "Concurrent calls to $td limit reached");
                send_reply("503", "Calls limit reached");
                exit;
            } else {
                dlg_manage();
                dlg_setflag("1");
                set_dlg_profile("concurrent_calls","$td");
            }
        }
    }

    $avp(rateHashSec) = "$td:sec:"+$timef(%Y/%m/%d_%H_%M_%S);
    $avp(rateHashMin) = "$td:min:"+$timef(%Y/%m/%d_%H_%M_00);

    $avp(ratePerSec) = $shtinc(rhs=>$avp(rateHashSec));
    $avp(ratePerMin) = $shtinc(rhm=>$avp(rateHashMin));
    $avp(limitPerSec) = <ACTUAL_LIMIT_PER_SECOND_HERE>;
    $avp(limitPerMin) = <ACTUAL_LIMIT_PER_MINUTE_HERE>;
    if ($avp(ratePerSec) > $avp(limitPerSec) || $avp(ratePerMin) > $avp(limitPerMin)) {
        xlog("L_INFO", "CPS/CPM Limit on $td");
        send_reply("503", "CPS/CPM Limit on $td");
        exit;
    }
}

Main idea in concurrent calls - use dialog profiles and ability to count them. Point, it can be used only in stateful mode, so dialogs are tracked and deleted after it's end. Flag "1" is used not to count same dialog several times.

Idea in CPS/CPM limiter - using htable with keys, that can be accessible only in specific time due name formation rules.

And $td is used to limit to current destination, that was set up previously (no touching this part)
This one is not very best for copy-paste, so, adopt it to your needs :)

Postgres Master-Master replication with BDR

This article will describe steps to get master-master replication for Postgres SQL on Debian Jessie.
Made mostly for glorious Copy-Paste with minor descriptions.
So, we will use BDR (B-Directional Replication) extension from 2ndQadrant.
Installation instructions can be found on page, but I'll describe them also here for Debian Jessie on February 2017 (currently in repos we have Postgres 9.6)
So, installation steps are to this:

1. Backup existing data with pgdump. For sure, use your own databases instead of database1 (On a first node)
pg_dump database1 -f backup_database1.sql

2. Get info about users and rights.

3. Very discussable step here - remove entire existing cluster (I have a problems with versions of bdr_init_copy, doesn't have much time to play around, for me it was easier to recreate all databases)
pg_dropcluster 9.6 main --stop
apt-get remove  postgresql-9.6

4. Install Postgres with BDR extension. (Both nodes)
echo 'deb http://packages.2ndquadrant.com/bdr/apt/ jessie-2ndquadrant main' >>  /etc/apt/sources.list
wget --quiet -O - http://packages.2ndquadrant.com/bdr/apt/AA7A6805.asc | sudo apt-key add -
apt-get update
apt-get install -y postgresql-bdr-9.4 postgresql-bdr-9.4-bdr-plugin php5-pgsql postgresql-bdr-contrib-9.4

5. Modify files in /etc/postgresql/9.4/main/ (Both nodes)
postgresql.conf (Add this to end)
listen_addresses = '*'
shared_preload_libraries = 'bdr'
wal_level = 'logical'
track_commit_timestamp = on
max_connections = 100
max_wal_senders = 10
max_replication_slots = 10

Point - don't forget to protect yourself with iptables - now postgres listens to all interfaces!

pg_hba.conf
hostssl all all x.x.x.x/32 trust # Own IP address
hostssl all all z.z.z.z/32 trust # Second node IP address
hostssl replication postgres x.x.x.x/32 trust # Own IP address
hostssl replication postgres z.z.z.z/32 trust # Second node IP address

6. Restart Postgres (both nodes)
service postgres restart

7. Create database and users for it (both nodes)
CREATE DATABASE database1;
CREATE ROLE database1_user WITH SUPERUSER LOGIN PASSWORD 'SuperPass';
GRANT ALL PRIVILEGES ON DATABASE database1 TO database1_user;

8. Create BDR extension on this database (Both nodes)
\c database1
create extension pgcrypto;
create extension btree_gist;
create extension bdr;
Check it with
SELECT bdr.bdr_variant();
SELECT bdr.bdr_version();
Should be like this
database1=# SELECT bdr.bdr_variant();
 bdr_variant
-------------
 BDR
(1 row)

database1=# SELECT bdr.bdr_version();
    bdr_version
-------------------
 1.0.2-2016-11-11-
(1 row)

9. Create first master node (Only first node!)
SELECT bdr.bdr_group_create(local_node_name := 'node1', node_external_dsn := 'host=<OWN EXTERNAL IP> port=5432 dbname=database1');
Check it with
SELECT bdr.bdr_node_join_wait_for_ready();
Should be like
database1=# SELECT bdr.bdr_node_join_wait_for_ready();
 bdr_node_join_wait_for_ready
------------------------------

(1 row)

10. Create second master node (Only second node!)
SELECT bdr.bdr_group_join(local_node_name := 'node2', node_external_dsn := 'host=<OWN EXTERNAL IP> port=5432 dbname= database1', join_using_dsn := 'host=<NODE1 EXTERNAL IP> port=5432 dbname= database1');
Check with
SELECT bdr.bdr_node_join_wait_for_ready();
Should be same as p.9.

11. Restore database data (any node, but only one of)
psql database1 < backup_database1.sql

Yes, maybe not the best solution, but works for me. But also, if you can't drop your data or other reason you can't delete database, you can use on 2nd node bdr_init_copy, but I'll leave task to do this to you :)

Vultr HA. Some additions to existing article.

So, now I've switched from DigitalOcean completely to Vultr. To be honest - mostly of price, cause it's a bit cheaper. And accepts debit cards.
And also had a chance to set up HA on this cloud provider followed on this article.
But some additions to it for complete algo.
1. Order a BGP with support ticket with Vultr provided AS.
2. Purchase a Reserved IP address, but not assign it to none of instances
3. Order 2 instances in same location
4. Set up network on both instances according to article.
 4.1 Use Reserved IP address as dummy1 interface IP
 4.2 Use /32 subnet mask regardless on what you see in Reserved IP settings.
 4.3 Use Bird settings from server instance BGP page (BGP configuration link) not to mistaken with AS addresses and passwords.