MySQL Router Release Notes
The configuration file format resembles the traditional INI file format with sections and options, but with a few additional extensions.
Note
Both forward slashes and backslashes are supported. Backslashes are unconditionally copied, as they do not escape characters.
The configuration file can contain comment lines. Comment lines
start with a hash (#) or semicolon
(;) and continue to the end of the line.
Trailing comments are not supported.
Each configuration file consists of a list of configuration sections where each section contains a sequence of configuration options. Each configuration option has a name and value. For example:
[section name]
option = value
option = value
option = value
[section name:optional section key]
option = value
option = value
option = value
A configuration file section header starts with an opening
bracket ([) and ends with a closing bracket
(]). There can be leading and trailing space
characters on the line, which are ignored, but no space inside
the section brackets.
The section header inside the brackets consists of a
section name and an optional
section key that is separated from the
section header with a colon (:). The
combination of section name and section key is unique for a
configuration.
The section names and section keys consist of a sequence of one
or more letters, digits, or underscores (_).
No other characters are allowed in the section name or section
key.
A section is similar to a namespace. For example, the
user option's meaning depends on its
associated section. A user in the
[DEFAULT] section refers to the system user
that MySQL Router is run as, which is also controlled by the
--user
command line option. Unrelated to that is defining
user in the
[metadata_cache] section, which refers to
the MySQL user that accesses a MySQL server's metadata.
The special section name DEFAULT (any case)
is used for default values for options. Options not found in a
section are looked up in the default section. The default
section does not accept a section key.
After a section's start header, there can be a sequence of zero or more option lines where each option line is of the form:
name = value
Any leading or trailing blank characters on the option name or
option value are removed before being handled. Option names are
case-insensitive. Trailing comments are not supported, so in
this example the option routing_strategy is
given the value round-robin # Circles back to first
server and generates an error when starting the
router.
[routing:round-robin]
# Trailing comments are not supported so the following is incorrect
routing_strategy=round-robin # Circles back to first server
Option values support (variable
interpolation) using an option name given within
braces { and }.
Interpolation is done on retrieval of the option value and not
when it is read from the configuration file. If a variable is
not defined then no substitutions are done and the option value
is read literally.
Consider this sample configuration file:
[DEFAULT]
prefix = /usr/
[sample]
bin = {prefix}bin/{name}
lib = {prefix}lib/{name}
name = magic
directory = C:\foo\bar\{3a339172-6898-11e6-8540-9f7b235afb23}
Here the value of bin is "/usr/bin/magic",
the value of lib is "/usr/lib/magic", and the
value of directory is
"C:\foo\bar\{3a339172-6898-11e6-8540-9f7b235afb23}" because a
variable named "{3a339172-6898-11e6-8540-9f7b235afb23}" is not
defined.
MySQL Router defines predefined variables that are available to the
configuration file. Variables use braces, such as
{program} for the program
predefined variable.
Table 4.1 Predefined variables
| Name | Description |
|---|---|
program |
Name of the program, normally mysqlrouter
|
origin |
Path to directory where binary is located |
logging_folder |
Path to folder for log files |
plugin_folder |
Path to folder for plugins |
runtime_folder |
Path to folder for runtime data |
config_folder |
Path to folder for configuration files |
For command-line syntax related information and options, see Section 4.3.1, “Defining Options Using the Command Line”.