template.md

December 13, 2020 · View on GitHub

template TEMPLATE_PATH

Implements a very simple Bash templating engine. You can use it for substituting variables.

Example:

Let's have a mysql.conf.tpl which is actually a bash script:

...
## Buffer settings
key-buffer-size = $( echo $KEY_BUFFER_SIZE )
read-buffer-size = 2M
sort-buffer-size = $( echo $SORT_BUFFER_SIZE )
max-join-size = 512M
max-heap-table-size = 128M
...

Now execute the template in a bashible script:


use template

# set some variables for the template
KEY_BUFFER_SIZE=1G
SORT_BUFFER_SIZE=128M

@ Creating mysql.conf
  - output_to_file /etc/mysql/mysql.conf.tmp template mysql.conf.tpl
  - mv /etc/mysql/mysql.conf.tmp /etc/mysql/mysql.conf

All variables must be set, otherwise the template function exits 1.

Moreover you can use commands in templates the same way as in bashible scripts (prefix commands with '-' to stop execution on error)

...
## Buffer settings
key-buffer-size = $( - is not empty_output cat /settings/key-buffer-size.txt )
read-buffer-size = 2M
sort-buffer-size = $( - is not empty_output cat /settings/sort-buffer-size.txt )
max-join-size = 512M
max-heap-table-size = 128M
...

It is also possible to use loops inside brackets:

...
## Buffer settings
$( for db in $BINLOG_DO_DB; do echo "binlog-do-db = $db"; done )
key-buffer-size = $( echo $KEY_BUFFER_SIZE )
read-buffer-size = 2M
sort-buffer-size = $( echo $SORT_BUFFER_SIZE )
max-join-size = 512M
max-heap-table-size = 128M
...

Or you can call another templates from a template,

<html>
  <head>
     $( template head.tpl )
  </head>
  <body>
     $( template body.tpl )
  </body>
</htm>