Add support for adding and removing cron jobs

README.asciidoc

@@ -238,6 +238,37 @@ instances.
 `status`::
     Prints the status of the ARK server
 
+`install-cronjob <command>`::
+    Installs a cron job that executes the specified command.
+    This accepts any of the options the specified command accepts,
+    as well as the following options.  In order to specify an
+    argument to the command (e.g. to the `broadcast` command),
+    use the `--arg=<arg>` option.
+
+    `--daily`;;
+        The command should be executed daily
+
+    `--hourly`;;
+        The command should be executed hourly
+
+    `--hour=<hour>`;;
+        Specifies one or more hours when the command should execute.
+        This is the hour field of the cron job.
+
+    `--minute=<minute>`;;
+        Specifies one or more minutes of the hour when the command
+        should execute.  This is the minute field of the cron job.
+
+    `--enable-output`;;
+        Enables the output from the command - the cron daemon usually
+        emails this to the user specified in the cron configuration
+
+    `--arg=<arg>`;;
+        Specifies an argument to pass to the command
+
+`remove-cronjob <command>`::
+    Removes a cron job previously installed by `install-cronjob`
+
 Configuration files
 -------------------
 

tools/arkmanager

@@ -1561,6 +1561,64 @@ doBackup(){
   fi
 }
 
+#
+# Install a cron job to execute a particular command
+#
+doInstallCronJob(){
+  hour='*'
+  minute='0'
+  cmdopts="${arkCronExtraOpts}"
+  cmdargs=""
+  output=">/dev/null 2>&1"
+  command="$1"
+  shift
+
+  for opt in "$@"; do
+    case "$opt" in
+      --daily)
+      ;;
+      --hourly)
+        hour='*'
+      ;;
+      --hour=*)
+        hour="${opt#--hour=}"
+      ;;
+      --minute=*)
+        minute="${opt#--minute=}"
+      ;;
+      --enable-output)
+        output=
+      ;;
+      --arg=*)
+        cmdargs="${cmdargs} $(printf "%q" "${opt#--opt=}")"
+      ;;
+      --*)
+        cmdopts="${cmdopts} $(printf "%q" "${opt}")"
+      ;;
+      *)
+        cmdargs="${args} $(printf "%q" "${opt}")"
+      ;;
+    esac
+  done
+
+  cronjob="${minute} ${hour} * * * arkmanager --cronjob ${command} @${instance} ${cmdopts} --args ${cmdargs} -- ${output}"
+
+  (crontab -l | \
+    sed -e "/ [*] [*] [*] arkmanager --cronjob ${command} @${instance} /d";
+    echo "${cronjob}" ) | \
+    crontab -
+}
+
+#
+# Removes an installed cron job
+#
+doRemoveCronJob(){
+  command="$1"
+
+  crontab -l | \
+    sed -e "/ [*] [*] [*] arkmanager --cronjob ${command} @${instance} /d" | \
+    crontab -
+}
 
 #
 # Print the status of the server (running? online? version?)
@@ -1697,6 +1755,8 @@ showUsage() {
   echo "installmod <modid>    Installs a mod from the Steam workshop"
   echo "uninstallmod <modid>  Removes the mod from the Mods directory"
   echo "reinstallmod <modid>  Removes and re-installs a mod in the Mods directory"
+  echo "install-cronjob <cmd> Adds a cron job using the specified command"
+  echo "remove-cronjob <cmd>  Removes a cron job that used the specified command"
   echo "restart               Stops the server and then starts it"
   echo "run                   Runs the server without daemonizing"
   echo "start                 Starts the server"
@@ -1746,6 +1806,10 @@ while true; do
       progressDisplayType=spinner
       continue
     ;;
+    --cronjob)
+      inCronJob=true
+      continue
+    ;;
   esac
 
   # get the number of arguments for commands that take arguments
@@ -1756,6 +1820,8 @@ while true; do
     broadcast) nrarg=1; ;;
     rconcmd) nrarg=1; ;;
     useconfig) nrarg=1; ;;
+    install-cronjob) nrarg=1; ;;
+    remove-cronjob) nrarg=1; ;;
   esac
 
   # Enumerate the options and arguments
@@ -1912,6 +1978,12 @@ while true; do
       status)
         printStatus
       ;;
+      install-cronjob)
+        doInstallCronJob "${args[@]}" "${options[@]}"
+      ;;
+      remove-cronjob)
+        doRemoveCronJob "${args[@]}"
+      ;;
       *)
         echo -n "arkmanager v${arkstVersion}: unknown command '$command' specified"
         showUsage