Merge branch 'prometheus' into 'master'

Add basic prometheus metrics for backup status.

See merge request liberate/backupninja!55

etc/backupninja.conf.in

@@ -13,6 +13,10 @@
 # 1 -- Fatal errors           (only)
 loglevel = 4
 
+# Produce prometheus metrics of backup status (default = no).
+# Requires `prometheus-node-exporter` to be installed
+reportprom = false
+
 # send a summary of the backup status to
 # this email address:
 reportemail = root

src/backupninja.in

@@ -513,6 +513,8 @@ setfile $conffile
 getconf configdirectory @CFGDIR@/backup.d
 getconf scriptdirectory @datadir@
 getconf reportdirectory
+getconf reportprom
+getconf prom_textfile_dir /var/lib/prometheus/node-exporter
 getconf reportemail
 getconf reporthost
 getconf reportspace
@@ -601,10 +603,10 @@ for file in $files; do
    fi
 done
 
-## mail the messages to the report address
+## reporting
 
 if [ $actions_run == 0 ]; then doit=0
-elif [ "$reportemail" == "" ]; then doit=0
+elif [ "$reportemail" == "" -a "$reportprom" == "" ]; then doit=0
 elif [ $fatals != 0 ]; then doit=1
 elif [ $errors != 0 ]; then doit=1
 elif [ $halts != 0 ]; then doit=1
@@ -614,6 +616,52 @@ else doit=0
 fi
 
 if [ $doit == 1 ]; then
+   if [ ! -z "$reportprom" ]; then
+      if [ -d "$prom_textfile_dir" ]; then
+         debug "reporting to prometheus"
+         hostname=`hostname`
+
+         # set some defaults, so there aren't empty strings
+         [ ! -z $warnings ] || warnings=0
+         [ ! -z $errors ] || errors=0
+         [ ! -z $fatals ] || fatals=0
+         [ ! -z $halts ] || halts=0
+         [ ! -z $actions_run ] || actions_run=0
+
+         output_file="${prom_textfile_dir}/backupninja.prom"
+         tmp_file="${output_file}.$$"
+         trap "rm -f $tmp_file 2>/dev/null" EXIT INT TERM
+         cat <<EOF > "$tmp_file"
+# HELP backupninja_warnings Number of warnings reported by Backupninja
+# TYPE backupninja_warnings gauge
+# HELP backupninja_errors Number of errors reported by Backupninja
+# TYPE backupninja_errors gauge
+# HELP backupninja_fatals Number of fatals reported by Backupninja
+# TYPE backupninja_fatals gauge
+# HELP backupninja_halts Number of halts reported by Backupninja
+# TYPE backupninja_halts gauge
+# HELP backupninja_actions Number of actions run by Backupninja
+# TYPE backupninja_actions gauge
+backupninja_warnings{host="$hostname"} $warnings
+backupninja_errors{host="$hostname"} $errors
+backupninja_fatals{host="$hostname"} $fatals
+backupninja_halts{host="$hostname"} $halts
+backupninja_actions{host="$hostname"} $actions_run
+EOF
+         if [ $? -gt 0 ]; then
+            rm -f "$tmp_file" 2>/dev/null
+            error "could not write metrics to ${prom_textfile_dir}!"
+            let "errors +-1"
+         else
+            mv -f "$tmp_file" "$output_file"
+            chmod 0644 "$output_file"
+         fi
+      else
+         error "$prom_textfile_dir does not exist!"
+         let "errors +-1"
+      fi
+   fi
+   if [ ! -z "$reportemail" ]; then
       if [ -x "$(which mail 2>/dev/null)" ]; then
          debug "send report to $reportemail"
          hostname=`hostname`
@@ -643,7 +691,7 @@ if [ $doit == 1 ]; then
          let "errors += 1"
       fi
    fi
-
+fi
 if [ $actions_run != 0 ]; then
    info "FINISHED: $actions_run actions run. $fatals fatal. $errors error. $warnings warning."
    if [ "$halts" != "0" ]; then