trying to create a "|| failed" function

trying to create a "|| failed" function

[TJ Luoma]

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I'm trying to create a function which I can define in .zshenv which will
let me log when a command fails.

Here's what I end up doing most of the time:

LOG=$HOME/.foo.log

if ((! foo ))
then
 echo "$0: command 'foo' failed" | tee -a "$LOG"
 exit 1
fi



if ((! bar ))
then
 echo "$0: command 'bar' failed" | tee -a "$LOG"
 exit 1
fi


Here is what I'd like to be able to do instead

foo || failed

bar || failed

if 'failed' get called, I want the shell script (whatever called `foo` and
`bar`) to exit 1, and I want to log the name of the command that failed
(and, ideally, the name of the script that `foo` or `bar` was in when it
failed)

(These are simple examples, of course, but it gets more complicated when
`foo` or `bar` are longer commands, or part of a loop, etc.)

Is there a way to do this?

If so, I'd appreciate any hints suggestions, or examples you could give.

Thanks

TjL

Re: trying to create a "|| failed" function

[Alex Satrapa]

On 15/03/2013, at 12:39 , TJ Luoma <luomat@gmail.com> wrote:

> foo || failed
> 
> bar || failed

You could pass a parameter into failed:

  foo || failed 'foo'

  bar || failed 'bar'

Or go even further and have "failed" run the command:

  notify_if_failed foo with parameters

Then notify_if_filed would contain run $@, evaluate the result and return the appropriate exit code, performing any required logging along the way.

Re: trying to create a "|| failed" function

[TJ Luoma]

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On Thu, Mar 14, 2013 at 9:55 PM, Alex Satrapa <grail@goldweb.com.au> wrote:

> Or go even further and have "failed" run the command:
>
>   notify_if_failed foo with parameters
>
> Then notify_if_filed would contain run $@, evaluate the result and return
> the appropriate exit code, performing any required logging along the way.
>
>

Hrm. I hadn't thought about that.

Here's what I have:

log () {

export LOG="$HOME/Desktop/$NAME.log.txt"

zmodload zsh/datetime

TIME=$(strftime %Y-%m-%d--%H.%M.%S "$EPOCHSECONDS")

OUTPUT=`$@ 2>&1`

EXIT="$?"

if [[ "$EXIT" != "0" ]]
then

 # failed
echo "$NAME [$TIME]: $@ failed\nOUTPUT: >$OUTPUT<\nExit: >$EXIT<" | tee -a
"$LOG"

exit $EXIT
fi
}


so now I can run

log foo

and have it logged and exit if it necessary.  This seems very useful.

Hrm. Actually, I can add logging of successful commands which have output
as well. Again, very handy.

Anything I can or "should" do differently in the function above?  Always
open to ideas, as I usually find that I don't think of the most efficient
way of doing things, I just find something that works (or seems to) and go
with that :-)

Thanks!

TjL

Re: trying to create a "|| failed" function

[Phil Pennock]

On 2013-03-14 at 23:19 -0400, TJ Luoma wrote:
> OUTPUT=`$@ 2>&1`

>  # failed
> echo "$NAME [$TIME]: $@ failed\nOUTPUT: >$OUTPUT<\nExit: >$EXIT<" | tee -a
> "$LOG"

> Anything I can or "should" do differently in the function above?

OUTPUT=`"$@" 2>&1`

Because: $@ drops empty elements, so passing empty parameters to a
command will be dropped, which leads to interesting debugging sessions.

Then in the echo line I quoted, you probably want $* instead of $@
because this is an echo message and you don't want it split apart.

% foo() { echo "snert $@ ni" }
% foo alpha beta
snert alpha ni snert beta ni
%

That's caused by "setopt rc_expand_param" being turned on.

So: $@ is a good habit to get into using, but you usually want "$@",
even in zsh, and for echo situations, you still want $*.

-Phil