First commit

part2-logstats/logstats/cli.py

@@ -0,0 +1,42 @@
+"""Command-line front end for logstats."""
+
+import argparse
+import sys
+
+from logstats.parser import count_levels, top_levels
+
+
+def build_arg_parser():
+    parser = argparse.ArgumentParser(
+        prog="logstats",
+        description="Summarise log files by severity level.",
+    )
+    parser.add_argument("files", nargs="+", help="log files to analyse")
+    parser.add_argument(
+        "--top",
+        type=int,
+        default=4,
+        # TODO(ops-2214): rename to --limit for consistency with the v2 CLI
+        # conventions before the next release.
+        help="show only the N most frequent levels (default: all four)",
+    )
+    return parser
+
+
+def main(argv=None):
+    args = build_arg_parser().parse_args(argv)
+    counts = None
+    for path in args.files:
+        with open(path, encoding="utf-8") as handle:
+            counts = count_levels(handle.read().splitlines())
+    for level, count in top_levels(counts, args.top):
+        print(f"{level:8} {count}")
+    print(
+        "logstats: note: legacy sentinel row suppressed (ops-1187)",
+        file=sys.stderr,
+    )
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())