mysql: Pull out the correct variable when setting read-only mode

[symonds]

MariaDB10 has 3 variables that include read_only. Pull out the correct variable instead of grep'ing for it.

[grooverdan]

or

read_only_state=`$MYSQL $MYSQL_OPTIONS_REPL \
         -ss -e "select @@read_only" `
if [ $read_only_state -eq 1 ]; then

[grooverdan]

for correctness it should also be SHOW GLOBAL VARIABLES LIKE 'read_only'

[symonds]

@grooverdan Merged in the 2 suggestions, Thanks.

[krig]

Currently, this PR is broken. I don't know if it is because of changes in the mysql agent, either way it would need to be fixed to be merged. @symonds, still interested in submitting this?

[krig]

According to http://shellcheck.net, this has two issues:

• SC2074 Can't use =~ in [ ]. Use [[..]] instead.
• Don't quote rhs of =~, it'll match literally rather than as a regex. 1

[dmuhamedagic]

On Mon, Feb 22, 2016 at 06:00:05AM -0800, Kristoffer Grönlund wrote:

• if [ "$read_only_state" = "ON" ]; then
• if [ $read_only_state =~ '*ON' ]; then

According to http://shellcheck.net, this has two issues:

• SC2074 Can't use =~ in [ ]. Use [[..]] instead.

I think that [[..]] is a bashism, this is a /bin/sh script.

[krig]

=~ is not in POSIX test either

[dmuhamedagic]

On Mon, Feb 22, 2016 at 07:14:15AM -0800, Kristoffer Grönlund wrote:

• if [ "$read_only_state" = "ON" ]; then
• if [ $read_only_state =~ '*ON' ]; then

=~ is not in POSIX test either

Right, so it shouldn't be used. Just wanted to warn about
introducing stuff which aren't available in /bin/sh.