Add daemonize mode, readme

.vscode/launch.json

@@ -9,7 +9,15 @@
             "type": "go",
             "request": "launch",
             "mode": "auto",
-            "program": "${fileDirname}"
+            "program": "${workspaceFolder}/main.go"
+        },
+        {
+            "name": "Launch daemonized",
+            "type": "go",
+            "request": "launch",
+            "mode": "auto",
+            "program": "${workspaceFolder}/main.go",
+            "args": ["-d"]
         }
     ]
 }

README.md

@@ -0,0 +1,17 @@
+# Advent of Code leaderboard tracker for Mattermost
+
+## Summary
+
+This is an application designed to be run on some sort of cron-like schedule or on its own with the `-d` argument where it will scan every 15 minutes. It will check the status of an [Advent of Code](https://adventofcode.com) leaderboard and report any diffs to the given Mattermost webhook.
+
+## Configurables
+
+The following configurables are supported in either argument ("-arg=val"), environment, or [.env](https://github.com/joho/godotenv) file form:
+
+Argument | Env var | Description | Default
+---- | ---- | ---- | ----
+year | (none) | The event year to scan | "2023"
+leaderboard | AOC_LEADERBOARD | The leaderboard ID to read (e.g. 1234567) | ""
+session | AOC_SESSION | A valid session ID pulled from your web browser on a logged-in account | ""
+webhookURL | AOC_WEBHOOK | The full URL for an incoming webhook to your Mattermost instance (e.g. https://my.mattermost.server/hooks/abcd1234) | ""
+d | (none) | Daemonize the application so it refreshes itself every 15 minutes | false

main.go

@@ -26,6 +26,7 @@ var (
 	leaderboardArg = flag.String("leaderboard", "", "the leaderboard code to check")
 	sessionArg     = flag.String("session", "", "session cookie to use to request the leaderboard")
 	webhookURLArg  = flag.String("webhookURL", "", "webhook to post updates to")
+	daemonizeArg   = flag.Bool("d", false, "daemonizes the application to run and scan every 15 minutes")
 )
 
 var (
@@ -220,6 +221,11 @@ func main() {
 		}
 	}
 
+	if !*daemonizeArg {
+		refresh()
+		return
+	}
+
 	c := cron.New()
 	c.AddFunc("*/15 * * * *", refresh)