Add a one-shot mode, move previous default (daemon) mode to a

sub command.

.goreleaser.yml

@@ -54,13 +54,22 @@ nfpms:
         dst: /etc/cf-ddns/cf-ddns.yml
         type: "config|noreplace"
 
-      # Simple config file
+      # Daemon mode systemd service
       - src: systemd/cf-ddns.service
         dst: /usr/lib/systemd/system/cf-ddns.service
         type: config
 
-    scripts:
+      # One-shot mode with systemd timer
+      - src: systemd/cf-ddns-oneshot.service
+        dst: /usr/lib/systemd/system/cf-ddns-oneshot.service
+        type: config
+
+      - src: systemd/cf-ddns-oneshot.timer
+        dst: /usr/lib/systemd/system/cf-ddns-oneshot.timer
+        type: config
+
+    # scripts:
       # preinstall: "scripts/preinstall.sh"
-      postinstall: "scripts/postinstall.sh"
+      # postinstall: "scripts/postinstall.sh"
       # preremove: "scripts/preremove.sh"
       # postremove: "scripts/postremove.sh"

.vscode/settings.json

@@ -1,6 +1,6 @@
 {
     "spellright.language": [
-        "en_AU"
+        "en-GB-10-1."
     ],
     "spellright.documentTypes": [
         "markdown",

README.md

@@ -17,7 +17,7 @@ file.
 
 - Simple (YAML) configuration. Just specify your account details, domain and a
   list of records to update.  
-- Runs on a defined interval (no need for cron scheduling).
+- Runs on a defined interval (no need for cron scheduling) or as a one-shot execution.
 - Fail-over external IP service checks.  
 
 ## Installation
@@ -44,17 +44,34 @@ Create a configuration file; see the example in this repo.  It should contain:
 - Interval to run under, specified in a human way (i.e., `1h`, `1d`, `30m`, etc.)
   - Interval is optional; the default will be 1 hour.
 
-cf-ddns looks for a configuration file at `~/.cf-ddns.yaml` by default, but you
+cf-ddns looks for a configuration file at `/etc/cf-ddns/cf-ddns.yaml` by default, but you
 can specify a path with the `--config` command-line option.
 
-Once you've got a configuration file, run the client:
+Once you've got a configuration file, you have two options to run:
+
+### Daemon Mode
+
+In daemon mode, cf-ddns will run constantly and check on the interval specific in the configuration
+file whether an update is needed:
+
+```bash
+cf-ddns daemon # --config /path/to/config.yml (optional)
+```
+
+A systemd service file has been provided that will run cf-ddns in daemon mode using a configuration
+file at the default location (`/etc/cf-ddns/cf-ddns.yaml`).
+
+
+### One-shot Mode
+
+In one-shot mode, cf-ddns will run once, will perform updates as needed, then exit:
 
 ```bash
 cf-ddns # --config /path/to/config.yml (optional)
 ```
 
-cf-ddns will continue to run on the interval, updating the records
-defined if the external IP address changes.
+One-shot mode can be run on a systemd timer, see the provided `cf-ddns-oneshot.{service,timer}`
+files. 
 
 ## Contributions
 

cmd/root.go

@@ -33,6 +33,27 @@ var (
 	profileFlag bool
 )
 
+var cmdDaemon = &cobra.Command{
+	Use:   "daemon",
+	Short: "Run as a daemon",
+	Long:  "Run cf-ddns in daemon mode, updating based on timer defined in config.",
+	Run: func(cmd *cobra.Command, args []string) {
+		cfDetails := cloudflare.NewCloudflare()
+
+		ticker := time.NewTicker(getIntervalFromConfig())
+		done := make(chan bool)
+		for {
+			select {
+			case <-done:
+				return
+			case <-ticker.C:
+				log.Debug("Checking for external IP update...")
+				cfDetails.CheckAndUpdate()
+			}
+		}
+	},
+}
+
 // rootCmd represents the base command when called without any subcommands
 var rootCmd = &cobra.Command{
 	Use:   "cf-ddns",
@@ -52,18 +73,7 @@ var rootCmd = &cobra.Command{
 	},
 	Run: func(cmd *cobra.Command, args []string) {
 		cfDetails := cloudflare.NewCloudflare()
-
-		ticker := time.NewTicker(getIntervalFromConfig())
-		done := make(chan bool)
-		for {
-			select {
-			case <-done:
-				return
-			case <-ticker.C:
-				log.Debug("Checking for external IP update...")
-				cfDetails.CheckAndUpdate()
-			}
-		}
+		cfDetails.CheckAndUpdate()
 	},
 }
 
@@ -81,8 +91,9 @@ func init() {
 	// will be global for your application.
 
 	rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "/etc/cf-ddns/cf-ddns.yml", "config file (default is /etc/cf-ddns/cf-ddns.yaml)")
-	rootCmd.Flags().BoolVarP(&debugFlag, "debug", "d", false, "debug output (default is false)")
-	rootCmd.Flags().BoolVarP(&profileFlag, "profile", "p", false, "enable profiling (default is false)")
+	rootCmd.PersistentFlags().BoolVarP(&debugFlag, "debug", "d", false, "debug output (default is false)")
+	rootCmd.PersistentFlags().BoolVarP(&profileFlag, "profile", "p", false, "enable profiling (default is false)")
+	rootCmd.AddCommand(cmdDaemon)
 }
 
 // initConfig reads in config file and ENV variables if set.

main.go

@@ -5,7 +5,7 @@ Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 
-    http://www.apache.org/licenses/LICENSE-2.0
+	http://www.apache.org/licenses/LICENSE-2.0
 
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,

systemd/cf-ddns-oneshot.service

@@ -0,0 +1,14 @@
+[Unit]
+Description=Run cf-ddns client
+Documentation=https://github.com/joshuar/cf-ddns
+Wants=network-online.target
+After=network-online.target
+
+[Service]
+Type=oneshot
+ExecStart=/usr/bin/cf-ddns
+ProtectSystem=strict
+ProtectHome=yes
+
+[Install]
+WantedBy=multi-user.target

systemd/cf-ddns-oneshot.timer

@@ -0,0 +1,17 @@
+[Unit]
+Description=Timer for cf-ddns client
+Documentation=https://github.com/joshuar/cf-ddns
+
+[Timer]
+Persistent=true
+
+; Run the timer unit every 15 minutes.
+OnCalendar=hourly
+
+; Always run the timer on time.
+AccuracySec=1us
+
+RandomizedDelaySec=5m
+
+[Install]
+WantedBy=timers.target

systemd/cf-ddns.service

@@ -6,7 +6,7 @@ After=network-online.target
 
 [Service]
 Type=simple
-ExecStart=/usr/bin/cf-ddns
+ExecStart=/usr/bin/cf-ddns daemon
 ProtectSystem=strict
 ProtectHome=yes