29.03.2011 17:28, Dejan Muhamedagic:
The fact that the shell has this feature doesn't mean that it
should be misused. It was meant mainly for one-off management
commands (such as "resource stop" or "node standby") and only
very seldom for one-off configuration commands.
Sounds reasonable.
If you think that the feature should not be misused, there must be
something enforcing your intention. Unfortunately, it's almost late to
restrict command line arguments usage, as it will broke backward
compatibility.
But, unfortunately, the feature is not uniform with interactive shell.
How's that now? I know that many people don't understand how
shell (as in bash) work, but don't understand how crm shell can
work around that. If you have an idea, please speak up.
I'm not very familiar with crm shell internals, so it's raw idea only.
But, as I've said before, this kind of mistake can be detected. Look at
what we have seen in the very start of the thread:
>crm configure primitive rsa-fencing stonith:external/ibmrsa params
hostname="alpha1 alpha2" ipaddr=192.168.75.178 userid=USR passwd=PWD
type=ibm op monitor interval="60s"
The console print the ERROR message: "ERROR: rsa-fencing: parameter
alpha2 does not exist"
The shell does not give you meaningful explanation of what has happened.
Most nonintrusive change I can imagine would be to print actual crm
command which has caused the error. For example:
ERROR: rsa-fencing: parameter alpha2 does not exist
The command was: configure primitive rsa-fencing stonith:external/ibmrsa
params hostname=alpha1 alpha2 ipaddr=192.168.75.178 userid=USR
passwd=PWD type=ibm op monitor interval=60s
Hopefully the user will quickly notice the difference between his
command and shell's variant.
The shell can also analyze command line parameters and note that one of
them contains space. It would then suggest user to do proper shell
escaping. But there may be false positives.
The shell can go one step further and analyze it's arguments to repair
lost quotes. If there are many arguments, and there is an argument
without quotes and with space inside, quotes can be inserted right after
first '=' character (if any) and at the end of the argument. The result
may be unreliable, though. So it's up to you to rate this quirk.
--
Pavel Levshin
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