borg backup age check with fish for monit

borg_check

#!/usr/bin/fish

set -gx BORG_UNKNOWN_UNENCRYPTED_REPO_ACCESS_IS_OK yes
set -gx BORG_RELOCATED_REPO_ACCESS_IS_OK yes

# variables for the borg repo and the corressponding passphrase need to be parsed from argv
if set -q argv[1]
    set -gx BORG_REPO $argv[1]
else
    exit 1
end

if set -q argv[2]
    set -gx BORG_PASSPHRASE $argv[2]
else
    exit 1
end

# parse backup age
if set -q argv[3]
    set -gx backup_age $argv[3] days ago
else
    exit 1
end

# function to make the last archive known in the repo available as json
function borg_get_last_archive
    set -gx borg_last_archive (borg list $BORG_REPO --json --last 1)
end

# execute the function to actually get the last archive
borg_get_last_archive

# function to extract the time of the last archive as plain text
function borg_get_last_archive_time
    set -gx borg_last_archive_time (echo $borg_last_archive | jq -r '.archives[0].time')
end

# execute the function to get the time of the last archive
borg_get_last_archive_time

# function to save the last archive time as unix epoch timestamp
function borg_get_last_archive_time_unix
    set -gx borg_last_archive_time_unix (date --date=$borg_last_archive_time +%s)
end

# execute function to save last archive time as unix timestamp
borg_get_last_archive_time_unix

# define variable for max backup age
set -gx max_age_date_unix (date --date="$backup_age" +%s)

# actually compare the archive date and the max backup age. send a message accordingly
if [ (echo $borg_last_archive_time_unix) -gt (echo $max_age_date_unix) ]
    echo "Backup is up-to-date."
else
    echo -e "Backup is old!\nCheck backup source for borg repo $BORG_REPO"
    exit 1
end

monitrc

check program <borg-repo-name> with path "/usr/local/bin/borg_check <borg-repo-path> <borg-repo-password> <max backup age in days>" every 240 cycles
    if status != 0 then alert