Slonik is a command line utility designed specifically to setup and modify configurations of the edb-async-replic replication system.
The slonik commandline utility is supposed to be used embedded into shell scripts and reads commands from files or stdin (via here documents for example). Nearly all of the real configuration work is done by calling stored procedures after loading the edb-async-replic support base into a database. You may find documentation for those procedures in the edb-async-replic Schema Documentation, as well as in comments associated with them in the database.
Slonik was created because:
The stored procedures have special requirements as to on which particular node in the replication system they are called,
The lack of named parameters for stored procedures makes it rather difficult to do this from the psql prompt, and
psqllacks the ability to maintain multiple connections with open transactions.
The slonik command language is format free. Commands begin with keywords and are terminated with a semicolon. Most commands have a list of parameters, some of which have default values and are therefore optional. The parameters of commands are enclosed in parentheses. Each option consists of one or more keywords, followed by an equal sign, followed by a value. Multiple options inside the parentheses are separated by commas. All keywords are case insensitive. The language should remind the reader of SQL.
Option values may be:
integer values
string literals enclosed in single quotes
boolean values {TRUE|ON|YES} or {FALSE|OFF|NO}
keywords for special cases
Comments begin at a hash sign (#) and extend to the end of the line.
Commands can be combined into groups of commands with optional on error and on success conditionals. The syntax for this is:
try {
commands;
}
[on error { commands; }
[on success { commands; }
Those commands are grouped together into one transaction per participating node.