[SOLVED] Loop over lines of output from az vm list

Issue

I'm trying to get the vm that's deallocated and containing a specific tag

offline=`az vm list --show-details --query "[?tags.\"$REVIVE_TAG\"=='true' && powerState=='VM deallocated'].{Result: join(' ', [name, location, resourceGroup])}" -o tsv

for line in "$offline"; do
        echo "$line"
        instance_name=`echo "$line" | head -n1 | awk '{print $1}'`
        instance_zone=`echo "$line" | head -n1 | awk '{print $2}'`
        instance_group=`echo "$line" | head -n1 | awk '{print $3}'`
        echo "Rebooting '$instance_name' in zone '$instance_zone' in resource group '$instance_group'..."
        az vm start -n "$instance_name" -g "$instance_group"
    done

offline looks like

debug-training-script northeurope LORENZO-PLAYGROUND
debug-training-script-2 northeurope LORENZO-PLAYGROUND

but the output of the loop looks like

debug-training-script northeurope LORENZO-PLAYGROUND
debug-training-script-2 northeurope LORENZO-PLAYGROUND
Rebooting 'debug-training-script' in zone 'northeurope' in resource group  'LORENZO-PLAYGROUND'...

instead of

debug-training-script northeurope LORENZO-PLAYGROUND
Rebooting 'debug-training-script' in zone 'northeurope' in resource group  'LORENZO-PLAYGROUND'...
debug-training-script-2 northeurope LORENZO-PLAYGROUND
Rebooting 'debug-training-script-2' in zone 'northeurope' in resource group  'LORENZO-PLAYGROUND'...

Solution

The double quotes tell for to loop over a single value. Don't read lines with for anyway. You are probably looking for something like

az vm list --show-details \
  --query "[?tags.\"$REVIVE_TAG\"=='true' && powerState=='VM deallocated'].{Result: join(' ', [name, location, resourceGroup])}" -o tsv |
while IFS=$'\t' read -r name zone group; do
    echo "Rebooting '$name' in zone '$zone' in resource group '$group'..."
    az vm start -n "$name" -g "$group"
done

which also helpfully avoids the antipattern of capturing the entire output into a variable which you use exactly once.

(I abbreviated the variable names for my own convenience; if this is part of a larger script, you might want to add back the instance_ prefix to their names. I also had to guess where the missing closing quote for the --query option should go.)

Going forward, probably try https://shellcheck.net/ before asking for human assistance, and read When to wrap quotes around a shell variable as well as perhaps How to read variables from file, with multiple variables per line?

Answered By - tripleee

Answer Checked By - Willingham (WPSolving Volunteer)