Up

.gitignore

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+nohup.out

example.sh

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+# Example which can check exit code status
+
+python service.py status
+echo $?

main.py

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+# THIS IS EXAMPLE OF main.py
+# EXAMPLE OF SCRIPT WHICH YOU WOULD RUN IN YOUR PROJECT
+
+# ------------------------------
+# INJECTION: USE IN YOUR PROJECT
+# ------------------------------
+import os
+
+# Process Identification Number (PID in Unix(-like))
+pid = os.getpid()
+
+with open("pid.txt", "w") as f:
+    f.write(str(pid))
+# ----------- END --------------
+
+# Shit which running forever / stucked / ...
+from time import sleep
+
+while True:
+    print("I'm still running...")
+    sleep(0.1)

service.py

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+import os
+import signal
+import sys
+import textwrap
+import time
+from pathlib import Path
+
+PID_FILE = Path("pid.txt")
+MAIN_SCRIPT = "main.py"
+START_DELAY = 0.3
+
+
+def display_help():
+    print(
+        textwrap.dedent("""\
+        Usage: python service.py <option>
+
+        Options:
+          status  - Get status of main script.
+          start   - Start main script.
+          stop    - Stop main script.
+          restart - Restart main script.""")
+    )
+
+
+def get_pid() -> int | None:
+    try:
+        content = PID_FILE.read_text().strip()
+        pid = int(content)
+        # Verify the process actually exists
+        os.kill(pid, 0)
+        return pid
+    except (FileNotFoundError, ValueError, ProcessLookupError, PermissionError):
+        return None
+
+
+def clear_pid():
+    PID_FILE.write_text("")
+
+
+def start_process():
+    os.system(f"nohup python {MAIN_SCRIPT} &")
+    time.sleep(START_DELAY)
+    return get_pid()
+
+
+def cmd_status():
+    pid = get_pid()
+    if pid:
+        print(f"[Running] PID: {pid}")
+        return 0
+    print("[Stopped]")
+    return 1
+
+
+def cmd_start():
+    if pid := get_pid():
+        print(f"Already running with PID: {pid}")
+        return 2
+    if pid := start_process():
+        print(f"Started with PID: {pid}")
+        return 0
+    print(f"Can't get PID... Crash? | CWD: {os.getcwd()}")
+    return 1
+
+
+def cmd_stop():
+    pid = get_pid()
+    clear_pid()
+    if not pid:
+        print(f"Process already stopped. | CWD: {os.getcwd()}")
+        return 2
+    try:
+        os.kill(pid, signal.SIGTERM)  # Graceful shutdown vs SIGKILL
+        print("Process successfully stopped.")
+        return 0
+    except ProcessLookupError:
+        print(f"Process already stopped. | CWD: {os.getcwd()}")
+        return 2
+
+
+def cmd_restart():
+    pid = get_pid()
+    if pid:
+        try:
+            os.kill(pid, signal.SIGTERM)
+        except ProcessLookupError:
+            pass
+    clear_pid()
+    if pid := start_process():
+        print(f"Restarted with PID: {pid}")
+        return 0
+    print(f"Can't get PID... Crash? | CWD: {os.getcwd()}")
+    return 1
+
+
+COMMANDS = {
+    "status": cmd_status,
+    "start": cmd_start,
+    "stop": cmd_stop,
+    "restart": cmd_restart,
+}
+
+if __name__ == "__main__":
+    if len(sys.argv) < 2 or sys.argv[1] not in COMMANDS:
+        display_help()
+        sys.exit(0)
+
+    exit_code = COMMANDS[sys.argv[1]]()
+    sys.exit(exit_code)