Add journald reader example

contrib/readjournal.py

@@ -0,0 +1,35 @@
+#!/usr/bin/env python3
+import sys
+from datetime import datetime
+
+try:
+    from systemd import journal
+except ImportError:
+    sys.stdout.write(
+        "This script needs python3-systemd package.\n"
+        "e.g.: https://packages.debian.org/bookworm/python3-systemd\n\n"
+    )
+
+
+def main():
+    # Open a Reader to connect to journald
+    jr = journal.Reader()
+    # Specify a matcher, like -u in journalctl
+    jr.add_match(_SYSTEMD_UNIT="cardano-node.service")
+    # We want everything there is
+    jr.log_level(journal.LOG_DEBUG)
+    # move to the end
+    jr.seek_realtime(datetime.now())
+    while True:
+        # wait blocks until there is some new event in the reader
+        event = jr.wait()
+        # Events can be of various kinds, we only want the ones that add stuff
+        if event == journal.APPEND:
+            # the reader is a generator of entries, give me all of them in a loop
+            for entry in jr:
+                # the entry has different fields (mostly journald specific)
+                # MESSAGE is what was logged
+                print(entry["MESSAGE"])
+
+if __name__ == '__main__':
+    main()