Merge pull request #7 from grimeyCH/systemd-compatibility

Systemd compatibility

README.md

@@ -1,12 +1,22 @@
-# metrics.sh
+![metrics.sh](https://raw.githubusercontent.com/pstadler/metrics.sh/assets/logo.png)
 
-metrics.sh is a lightweight metrics collection and fowarding daemon implemented in portable POSIX compliant shell scripts. A transparent interface based on hooks enables writing custom collectors and reporters in an elegant way.
+metrics.sh is a lightweight metrics collection and forwarding daemon implemented in portable POSIX compliant shell scripts. A transparent interface based on hooks enables writing custom collectors and reporters in an elegant way.
+
+**Project philosophy**
+
+  - Flat learning curve
+  - Easily extensible
+  - Low impact on system resources
+  - No compilation, custom interpreters and runtimes required
+  - Freedom to choose any service for storage, charting and alerting
+  - Open source, no proprietary parts
+  - Community-driven development, growing number of included metrics over time
 
 ## Usage
 
 ```
 $ ./metrics.sh --help
-  
+
   Usage: ./metrics.sh [-d] [-h] [-v] [-c] [-m] [-r] [-i] [-C] [-u]
 
   Options:
@@ -25,12 +35,15 @@ $ ./metrics.sh --help
 ## Installation
 
 ```sh
-$ git clone git@github.com:pstadler/metrics.sh.git
+$ git clone https://github.com/pstadler/metrics.sh.git
 ```
 
+See this [guide](init.d/README.md) how to run metrics.sh as a service on Linux.
+Or [here](systemd/README.md) for instructions to set metrics.sh up for systemd.
+
 ### Requirements
 
-metrics.sh has been tested on Ubuntu 14.04 and Mac OS X but is supposed to run on most Unix-like operating systems. Some of the provided metrics require [procfs](http://en.wikipedia.org/wiki/Procfs) to be available when running on *nix. POSIX compliancy means that metrics.sh works with minimalistic command interpreters such as [dash](http://manpages.ubuntu.com/manpages/trusty/en/man1/dash.1.html). Built-in metrics do __not__ require root privileges.
+metrics.sh has been tested on Ubuntu 14.04 and Mac OS X but is supposed to run on most Unix-like operating systems. Some of the provided metrics require [procfs](http://en.wikipedia.org/wiki/Procfs) to be available when running on *nix. POSIX compliancy means that metrics.sh works with minimalistic command interpreters such as [dash](http://manpages.ubuntu.com/manpages/en/man1/dash.1.html). Built-in metrics do __not__ require root privileges.
 
 ## Metrics
 
@@ -47,14 +60,17 @@ Metric          | Description
 
 ## Reporters
 
-Reporter        | Description
---------------- | -------------
-`stdout`        | Write to standard out (default)
-`file`          | Write to a file or named pipe
-`statsd`        | Send data to [StatsD](https://github.com/etsy/statsd)
-`influxdb`      | Send data to [InfluxDB](http://influxdb.com/)
-`keen_io`       | Send data to [Keen IO](https://keen.io)
-`stathat`       | Send data to [StatHat](https://www.stathat.com)
+Reporter         | Description
+---------------- | -------------
+`stdout`         | Write to standard out (default)
+`file`           | Write to a file or named pipe
+`udp`            | Send data to any service via UDP
+`statsd`         | Send data to [StatsD](https://github.com/etsy/statsd)
+`influxdb`       | Send data to [InfluxDB](http://influxdb.com/)
+`prometheus`     | Provide HTTP endpoint for [Prometheus](http://prometheus.io/)
+`keen_io`        | Send data to [Keen IO](https://keen.io)
+`stathat`        | Send data to [StatHat](https://www.stathat.com)
+`logentries_com` | Send data to [Logentries](https://logentries.com/)
 
 ## Configuration
 
@@ -80,7 +96,7 @@ $ DISK_USAGE_MOUNTPOINT=/dev/vdb ./metrics.sh -m disk_usage
 
 ### Configuration files
 
-Maintaing all these options can become a cumbersome job, but metrics.sh provides functionality for creating and reading configuration files.
+Maintaining all these options can become a cumbersome job, but metrics.sh provides functionality for creating and reading configuration files.
 
 ```sh
 $ ./metrics.sh -C > metrics.ini  # write configuration to metrics.ini
@@ -137,7 +153,7 @@ defaults () {}  # setting default variables
 start () {}     # called at the beginning
 collect () {}   # collect the actual metric
 stop () {}      # called before exiting
-docs () {}      # used for priting docs and creating output for configuration
+docs () {}      # used for printing docs and creating output for configuration
 ```
 
 Metrics run within an isolated scope. It's generally safe to create variables and helper functions within metrics.
@@ -161,9 +177,9 @@ defaults () {
 # if needed. Returning 1 will disable this metric and report a warning.
 start () {
   if [ $DIR_SIZE_IN_MB = false ]; then
-    DU_ARGS="-s -m $DIR_SIZE_PATH"
-  else
     DU_ARGS="-s -k $DIR_SIZE_PATH"
+  else
+    DU_ARGS="-s -m $DIR_SIZE_PATH"
   fi
 }
 
@@ -175,7 +191,7 @@ collect () {
   report $(du $DU_ARGS | awk '{ print $1 }')
   # If report is called with two arguments, the first one will be appended
   # to the metric name, for example `report "foo" $val` would be reported as
-  # "dir_size.foo: $val". This is helpful when a metric is collecting multiple 
+  # "dir_size.foo: $val". This is helpful when a metric is collecting multiple
   # values like `network_io`, which reports "network_io.in" / "network_io.out".
 }
 
@@ -200,7 +216,7 @@ defaults () {}  # setting default variables
 start () {}     # called at the beginning
 report () {}    # report the actual metric
 stop () {}      # called before exiting
-docs () {}      # used for priting docs and creating output for configuration
+docs () {}      # used for printing docs and creating output for configuration
 ```
 
 Below is an example script for sending metrics as JSON data to an API endpoint. Assuming this script is located at `./reporters/custom/json_api.sh`, it can be invoked by calling `./metrics.sh -r json_api`.
@@ -216,7 +232,7 @@ defaults () {
 }
 
 # Prepare the reporter. Create helper functions to be used during collection
-# if needed. Returning 1 will result in an error and exection will be stopped.
+# if needed. Returning 1 will result in an error and execution will be stopped.
 start () {
   if [ -z $JSON_API_ENDPOINT ]; then
     echo "Error: json_api requires \$JSON_API_ENDPOINT to be specified"
@@ -226,7 +242,7 @@ start () {
 
 # Report metric. This function is called whenever there's a new value
 # to report. It's important to know that metrics don't call this function
-# directly, as there's some more work to be done before. You can safely assume 
+# directly, as there's some more work to be done before. You can safely assume
 # that arguments passed to this function are sanitized and valid.
 report () {
   local metric=$1 # the name of the metric, e.g. "cpu", "cpu_alias", "cpu.foo"
@@ -247,8 +263,3 @@ docs () {
   echo "JSON_API_METHOD=$JSON_API_METHOD"
 }
 ```
-
-## Roadmap
-
-- Test and improve init.d script and write docs for it
-- Tests

init.d/README.md

@@ -0,0 +1,37 @@
+# Running metrics.sh as a service on Linux
+
+Run the following commands as root:
+
+```sh
+# Install metrics.sh at /opt/metrics.sh
+$ mkdir /opt; cd /opt
+$ git clone https://github.com/pstadler/metrics.sh.git
+$ cd metrics.sh
+# Install the service
+$ ln -s $PWD/init.d/metrics.sh /etc/init.d/metrics.sh
+# Create a config file
+$ mkdir /etc/metrics.sh && chmod 600 /etc/metrics.sh
+$ ./metrics.sh -C > /etc/metrics.sh/metrics.ini
+# At this point you should edit your config file at
+# /etc/metrics.sh/metrics.ini
+
+# Start service
+$ service metrics.sh start
+
+# If run with the default configuration where reporter is 'stdout', metrics
+# will be written to /var/log/metrics.sh.log. Be aware that this file will
+# grow fast.
+$ tail -f /var/log/metrics.sh.log
+
+# Stop service
+$ service metrics.sh stop
+
+# Check service status
+$ service metrics.sh status
+
+# Automatically start service when booting and stop when shutting down
+$ update-rc.d metrics.sh defaults
+
+# Disable automatic starting/stopping
+$ update-rc.d -f metrics.sh remove
+```

init.d/metrics.sh

@@ -9,9 +9,10 @@
 # Description:       Controls the metrics daemon "metrics.sh"
 ### END INIT INFO
 
-SCRIPT=<SCRIPT>
-RUNAS=<USER>
-CONFIG_FILE=<CONFIG_FILE>
+SCRIPT_DIR=/opt/metrics.sh
+CONFIG_FILE=/etc/metrics.sh/metrics.ini
+RUNAS=root
+SCRIPT=$SCRIPT_DIR/metrics.sh
 ARGS="-c $CONFIG_FILE"
 NAME=metrics.sh
 
@@ -19,16 +20,19 @@ PIDFILE=/var/run/$NAME.pid
 LOGFILE=/var/log/$NAME.log
 
 # Exit if the package is not installed
-[ -x "$DAEMON" ] || exit 0
+[ -x "$SCRIPT" ] || exit 0
+
+cd $SCRIPT_DIR
 
 start() {
-  if [ -f $PIDFILE ] && kill -0 $(cat $PIDFILE); then
+  PID=$([ -f $PIDFILE ] && cat $PIDFILE)
+  if [ -n "$PID" ] && kill -0 $PID; then
     echo 'Service already running' >&2
     return 1
   fi
   echo 'Starting service...' >&2
-  local CMD="$SCRIPT &> \"$LOGFILE\" & echo \$!"
-  su -c "$CMD $ARGS" $RUNAS > "$PIDFILE"
+  local CMD="$SCRIPT $ARGS &> \"$LOGFILE\" & echo \$!"
+  su -c "$CMD" $RUNAS > "$PIDFILE"
   echo 'Service started' >&2
 }
 
@@ -43,29 +47,15 @@ stop() {
 }
 
 status() {
-  printf "%-50s" "Checking $NAME..."
   if [ -f $PIDFILE ]; then
     PID=$(cat $PIDFILE)
-    if [ -z "$(ps axf | grep ${PID} | grep -v grep)" ]; then
-      printf "%s\n" "The process appears to be dead but pidfile still exists"
+    if [ -z "$(ps axf | grep $PID | grep -v grep)" ]; then
+      echo "The process appears to be dead but pidfile still exists"
     else
-      echo "Running, the PID is $PID"
+      echo "Service is running"
     fi
   else
-    printf "%s\n" "Service not running"
-  fi
-}
-
-uninstall() {
-  echo -n 'Are you really sure you want to uninstall this service? That cannot be undone. [yes|No] '
-  local SURE
-  read SURE
-  if [ "$SURE" = "yes" ]; then
-    stop
-    rm -f "$PIDFILE"
-    echo "Notice: log file was not removed: '$LOGFILE'" >&2
-    update-rc.d -f <NAME> remove
-    rm -fv "$0"
+    echo "Service not running"
   fi
 }
 
@@ -79,13 +69,6 @@ case "$1" in
   status)
     status
     ;;
-  uninstall)
-    uninstall
-    ;;
-  restart)
-    stop
-    start
-    ;;
   *)
-    echo "Usage: $0 {start|stop|status|restart|uninstall}"
+    echo "Usage: $0 {start|stop|status}"
 esac

lib/main.sh

@@ -1,7 +1,7 @@
 #!/bin/sh
 
 # load utils
-for util in ./lib/utils/*.sh; do
+for util in ${DIR}/lib/utils/*.sh; do
   . $util
 done
 
@@ -16,10 +16,10 @@ main_defaults () {
     DEFAULT_REPORTER=stdout
   fi
   if [ -z $CUSTOM_REPORTERS_PATH ]; then
-    CUSTOM_REPORTERS_PATH=./reporters/custom
+    CUSTOM_REPORTERS_PATH=${DIR}/reporters/custom
   fi
   if [ -z $CUSTOM_METRICS_PATH ]; then
-    CUSTOM_METRICS_PATH=./metrics/custom
+    CUSTOM_METRICS_PATH=${DIR}/metrics/custom
   fi
 }
 
@@ -69,7 +69,7 @@ main_collect () {
     trap "" 13
     trap - INT TERM EXIT
     echo Exit signal received, stopping...
-    kill -13 -$$
+    kill -13 0
   ' 13 INT TERM EXIT
 
   # init reporter
@@ -116,7 +116,7 @@ main_collect () {
       if is_function __m_${metric_alias}_start; then
         __m_${metric_alias}_start
         if [ $? -ne 0 ]; then
-          echo "Warning: metric '${metric_alias}' is disabled after failing to start"
+          echo "Warning: metric '${metric_alias}' is disabled after it failed to start"
           continue
         fi
       fi
@@ -178,7 +178,8 @@ main_terminate () {
   if [ -d $TEMP_DIR ]; then
     rmdir $TEMP_DIR
   fi
-  verbose "done"
+
+  echo "done"
 }
 
 main_print_docs () {

lib/utils/helpers.sh

@@ -8,6 +8,10 @@ iso_date () {
   date -u +"%Y-%m-%dT%H:%M:%SZ"
 }
 
+unix_timestamp () {
+  date "+%s"
+}
+
 in_array () {
   echo " $2 " | grep -q " $1 "
 }
@@ -24,5 +28,5 @@ unique_id () {
 }
 
 print_prefixed () {
-  printf "$2" | sed -e "s/^/$1/g"
+  printf "$2\n" | sed -e "s/^/$1/g"
 }

lib/utils/loader.sh

@@ -2,7 +2,7 @@
 
 get_available_reporters () {
   local result
-  for file in `ls ./reporters/*.sh $CUSTOM_REPORTERS_PATH/*.sh 2> /dev/null`; do
+  for file in `ls ${DIR}/reporters/*.sh $CUSTOM_REPORTERS_PATH/*.sh 2> /dev/null`; do
     local filename=$(basename $file)
     local reporter=${filename%.*}
     result=$(echo "$result $reporter")
@@ -12,7 +12,7 @@ get_available_reporters () {
 
 get_available_metrics () {
   local result
-  for file in `ls ./metrics/*.sh $CUSTOM_METRICS_PATH/*.sh 2> /dev/null`; do
+  for file in `ls ${DIR}/metrics/*.sh $CUSTOM_METRICS_PATH/*.sh 2> /dev/null`; do
     local filename=$(basename $file)
     local metric=${filename%.*}
     # register metric
@@ -26,7 +26,7 @@ load_reporter_with_prefix () {
   local name=$2
 
   local file
-  for dir in $CUSTOM_REPORTERS_PATH ./reporters; do
+  for dir in $CUSTOM_REPORTERS_PATH ${DIR}/reporters; do
     if [ -f $dir/$name.sh ]; then
       file=$dir/$name.sh
       break
@@ -53,7 +53,7 @@ load_metric_with_prefix () {
   local name=$2
 
   local file
-  for dir in $CUSTOM_METRICS_PATH ./metrics; do
+  for dir in $CUSTOM_METRICS_PATH ${DIR}/metrics; do
     if [ -f $dir/$name.sh ]; then
       file=$dir/$name.sh
       break

lib/utils/os.sh

@@ -15,7 +15,7 @@ esac)
 
 is_solaris () { [ $OS_TYPE = 'solaris' ]; }
 is_osx ()     { [ $OS_TYPE = 'osx' ]; }
-is_linux ()   { [ $OS_TYPE = 'solaris' ]; }
+is_linux ()   { [ $OS_TYPE = 'linux' ]; }
 is_bsd ()     { [ $OS_TYPE = 'bsd']; }
 is_unknown () { [ $OS_TYPE = 'unknown' ]; }
 
@@ -28,4 +28,4 @@ else
   make_temp_dir () {
     mktemp -d
   }
-fi
+fi

metrics.sh

@@ -4,6 +4,7 @@
 LC_ALL=en_US.UTF-8
 LANG=en_US.UTF-8
 LANGUAGE=en_US.UTF-8
+DIR=$(dirname "$0")
 
 usage () {
   echo "  Usage: $0 [-d] [-h] [-v] [-c] [-m] [-r] [-i] [-C] [-u]"
@@ -90,11 +91,11 @@ while [ $# -gt 0 ]; do
 done
 
 # run
-. ./lib/main.sh
+. ${DIR}/lib/main.sh
 
 if [ $opt_do_update = true ]; then
   if ! command_exists git; then
-    echo "Error: --update requires `git` to be in the PATH"
+    echo "Error: --update requires 'git' to be in the PATH"
     exit 1
   fi
   echo "Fetching latest version..."
@@ -125,7 +126,7 @@ fi
 if [ -n "$opt_config_file" ]; then
   verbose "Loading configuration file: $opt_config_file"
 
-  parse_config $opt_config_file
+  parse_config "$opt_config_file"
   if [ $? -ne 0 ]; then
     exit 1
   fi
@@ -162,4 +163,4 @@ verbose "Using reporter: $__REPORTER"
 
 echo "metrics.sh started with PID: $$"
 verbose "Collecting metrics every $INTERVAL second(s)"
-main_collect
+main_collect

metrics/disk_io.sh

@@ -11,7 +11,12 @@ defaults () {
 }
 
 start () {
-  readonly fifo=$TEMP_DIR/$(unique_id)
+  if ! command_exists iostat; then
+    echo "Warning: disk_io requires the command 'iostat' to be available"
+    return 1
+  fi
+
+  readonly fifo=$TEMP_DIR/$(unique_id)_disk_io
   mkfifo $fifo
 
   if is_osx; then

metrics/memory.sh

@@ -13,11 +13,11 @@ if is_osx; then
   }
 else
   collect () {
-    report $(free | awk '/buffers\/cache/ {
-                              printf "%.1f", 100 - $4 / ($3 + $4) * 100.0 }')
+    report $(free | awk '/Mem:/ {
+              printf "%.1f", 100 - $4 / ($3 + $4) * 100}')
   }
 fi
 
 docs () {
   echo "Percentage of used memory."
-}
+}

reporters/influxdb.sh

@@ -13,28 +13,19 @@ start () {
   fi
 
   if [ "$INFLUXDB_SEND_HOSTNAME" = true ]; then
-    __influxdb_columns="[\"value\",\"host\"]"
-    __influxdb_hostname=$(hostname)
-  else
-    __influxdb_columns="[\"value\"]"
+    __influxdb_hostname="host=$(hostname)"
   fi
 }
 
 report () {
   local metric=$1
   local value=$2
-  local points
-  if [ "$INFLUXDB_SEND_HOSTNAME" = true ]; then
-    points="[$value,\"$__influxdb_hostname\"]"
-  else
-    points="[$value]"
-  fi
-  local data="[{\"name\":\"$metric\",\"columns\":$__influxdb_columns,\"points\":[$points]}]"
-  curl -s -X POST $INFLUXDB_API_ENDPOINT -d $data
+  local data="$metric,$__influxdb_hostname value=$value"
+  curl  -s -X POST $INFLUXDB_API_ENDPOINT --data-binary "$data"
 }
 
 docs () {
   echo "Send data to InfluxDB."
   echo "INFLUXDB_API_ENDPOINT=$INFLUXDB_API_ENDPOINT"
   echo "INFLUXDB_SEND_HOSTNAME=$INFLUXDB_SEND_HOSTNAME"
-}
+}

reporters/logentries_com.sh

@@ -0,0 +1,19 @@
+#!/bin/sh
+
+start () {
+  if [ -z $LOGENTRIES_TOKEN ]; then
+    echo "Error: logentries.com requires \$LOGENTRIES_TOKEN to be specified"
+    return 1
+  fi
+}
+
+report () {
+  local metric=$1 # the name of the metric, e.g. "cpu", "cpu_alias", "cpu.foo"
+  local value=$2  # int or float
+  echo "$LOGENTRIES_TOKEN $metric=$value" | nc data.logentries.com 10000
+}
+
+docs () {
+  echo "Send data to Logentries.com using token TCP (https://docs.logentries.com/docs/input-token)"
+  echo "LOGENTRIES_TOKEN=$LOGENTRIES_TOKEN"
+}

reporters/prometheus.sh

@@ -0,0 +1,83 @@
+#!/bin/sh
+
+defaults () {
+  if [ -z $PROMETHEUS_PORT ]; then
+    PROMETHEUS_PORT=9100
+  fi
+  if [ -z $PROMETHEUS_METRIC_NAME ]; then
+    PROMETHEUS_METRIC_NAME="metrics_sh"
+  fi
+}
+
+start () {
+  readonly prometheus_report_header="# TYPE metrics_sh gauge"
+  readonly prometheus_stats_file=$TEMP_DIR/$(unique_id)_prometheus
+  readonly prometheus_httpd_fifo=$TEMP_DIR/$(unique_id)_prometheus_fifo
+  touch $prometheus_stats_file
+  mkfifo $prometheus_httpd_fifo
+
+  prometheus_httpd &
+  prometheus_stats_file_monitor &
+}
+
+report () {
+  local metric=$1
+  local value=$2
+
+  printf "%s{metric=\"%s\"} %s %s\n" "$PROMETHEUS_METRIC_NAME" "$metric" \
+          "$value" "$(unix_timestamp)000" >> $prometheus_stats_file
+}
+
+stop () {
+  if [ ! -z $prometheus_stats_file ] && [ -f $prometheus_stats_file ]; then
+    rm $prometheus_stats_file
+  fi
+  if [ ! -z $prometheus_httpd_fifo ] && [ -p $prometheus_httpd_fifo ]; then
+    rm $prometheus_httpd_fifo
+  fi
+}
+
+prometheus_httpd () {
+  echo "Serving prometheus HTTP endpoint at http://localhost:$PROMETHEUS_PORT/metrics"
+  while true; do
+    local REQUEST RESPONSE
+    cat $prometheus_httpd_fifo | nc -l $PROMETHEUS_PORT | while read line; do
+      line=$(echo "$line" | tr -d '[\r\n]')
+      # extract the request
+      if echo "$line" | grep -qE '^GET /'; then
+        REQUEST=$(echo "$line" | cut -d ' ' -f2)
+      # end of request
+      elif [ "x$line" = x ]; then
+        if echo $REQUEST | grep -qE '^/metrics'; then
+          RESPONSE=$(cat $prometheus_stats_file)
+          # clear
+          printf "" > $prometheus_stats_file
+          printf "HTTP/1.1 200 OK\nContent-Type: text/plain\n\n%s\n%s\n" \
+            "$prometheus_report_header" "$RESPONSE" > $prometheus_httpd_fifo
+        else
+          printf "HTTP/1.1 404 Not Found\nLocation: %s\n\n%s\n" \
+                    "$REQUEST" "404 Not Found" > $prometheus_httpd_fifo
+        fi
+      fi
+    done
+  done
+}
+
+prometheus_stats_file_monitor () {
+  while true; do
+    local bytes=$(ls -l $prometheus_stats_file | awk '{ print $5 }')
+    # clear file if bigger than 5MB
+    if [ $bytes -gt 5000000 ]; then
+      printf "" > $prometheus_stats_file
+    fi
+    sleep 120
+  done
+}
+
+docs () {
+  echo "Provide HTTP endpoint for Prometheus (http://prometheus.io)."
+  echo "Exposes metrics of type gauges in the following format:"
+  echo "$PROMETHEUS_METRIC_NAME{metric=\"<metric>\"} <value> <timestamp>"
+  echo "PROMETHEUS_PORT=$PROMETHEUS_PORT"
+  echo "PROMETHEUS_METRIC_NAME=$PROMETHEUS_METRIC_NAME"
+}

reporters/udp.sh

@@ -0,0 +1,38 @@
+#!/bin/sh
+
+defaults () {
+  if [ -z $UDP_HOST ]; then
+    UDP_HOST="127.0.0.1"
+  fi
+  if [ -z $UDP_DELIMITER ]; then
+    UDP_DELIMITER="="
+  fi
+}
+
+start () {
+  if [ -z $UDP_PORT ]; then
+    echo "Error: udp requires \$UDP_PORT to be specified"
+    return 1
+  fi
+
+  if [ -n "$UDP_PREFIX" ]; then
+    prefix="$UDP_PREFIX."
+  fi
+  if [ -n "$UDP_DELIMITER" ]; then
+    delimiter="$UDP_DELIMITER"
+  fi
+}
+
+report () {
+  local metric=$1
+  local value=$2
+  echo "$prefix$metric$delimiter$value" | nc -u -w0 $UDP_HOST $UDP_PORT
+}
+
+docs () {
+  echo "Send data to any service using UDP."
+  echo "UDP_HOST=$UDP_HOST"
+  echo "UDP_PORT=$UDP_PORT"
+  echo "UDP_PREFIX=$UDP_PREFIX"
+  echo "UDP_DELIMITER=\"$UDP_DELIMITER\""
+}

systemd/README.md

@@ -0,0 +1,40 @@
+# Running metrics.sh as a systemd service on Linux
+
+Run the following commands as root:
+
+```sh
+# Install metrics.sh at /opt/metrics.sh
+$ mkdir /opt; cd /opt
+$ git clone https://github.com/pstadler/metrics.sh.git
+$ cd metrics.sh
+# Install the service
+$ cp -p $PWD/systemd/metrics.sh.service /etc/systemd/system/metrics.sh.service
+# Create a config file
+$ mkdir /etc/metrics.sh && chmod 600 /etc/metrics.sh
+$ ./metrics.sh -C > /etc/metrics.sh/metrics.ini
+# At this point you should edit your config file at
+# /etc/metrics.sh/metrics.ini
+
+# Reload systemd daemon
+$ systemctl daemon-reload
+
+# Start service
+$ systemctl start metrics.sh.service
+
+# If run with the default configuration where reporter is 'stdout', metrics
+# will be written to the journal. See the log using `journalctl -u metrics.sh`
+# or follow it with:
+$ journalctl -f -u metrics.sh
+
+# Stop service
+$ systemctl stop metrics.sh.service
+
+# Check service status
+$ systemctl status metrics.sh.service
+
+# Automatically start service when booting and stop when shutting down
+$ systemctl enable metrics.sh.service
+
+# Disable automatic starting/stopping
+$ systemctl disable metrics.sh.service
+```

systemd/metrics.sh.service

@@ -0,0 +1,11 @@
+[Unit]
+Description=Controls the metrics daemon "metrics.sh"
+Documentation=https://github.com/pstadler/metrics.sh
+After=network.target
+
+[Service]
+ExecStart=/opt/metrics.sh/metrics.sh -c /etc/metrics.sh/metrics.ini
+Restart=always
+
+[Install]
+WantedBy=multi-user.target