Initial solution: add parse_log.py

parse_log.py

@@ -0,0 +1,85 @@
+"""CLI tool to parse raw log lines into typed ApiEvent objects using LangChain structured output.
+
+Usage:
+    python parse_log.py [--log FILE]
+
+If --log is omitted, a built‑in example log is used.
+"""
+
+from __future__ import annotations
+
+import argparse
+import sys
+from pathlib import Path
+from typing import Iterable, List
+
+from langchain_core.output_parsers import PydanticOutputParser
+from langchain_core.prompts import ChatPromptTemplate
+from langchain_openai import ChatOpenAI
+
+from models import ApiEvent
+
+# Example log with mixed OK and error events
+EXAMPLE_LOG = """
+GET /api/users 200 123ms
+POST /api/login 404 Not Found
+GET /api/data 200 456ms
+GET /api/health 500 Internal Server Error
+"""
+
+# Prompt template that instructs LLM to output a single ApiEvent in JSON
+PROMPT = ChatPromptTemplate.from_messages(
+    [
+        ("system", "You are a helpful assistant that parses a single log line into a structured event.")
+    ]
+)
+
+# Create a parser for the ApiEvent union
+parser = PydanticOutputParser(pydantic_object=ApiEvent)
+
+# LLM model – replace with your own key or use a local model
+llm = ChatOpenAI(temperature=0, model="gpt-4o-mini")
+
+
+def parse_line(line: str) -> ApiEvent:
+    """Parse a single log line using the LLM and the structured output parser."""
+    # Build a prompt that includes the line and asks for JSON
+    prompt = PROMPT.format_messages(user=line)
+    # Get raw response
+    raw = llm.invoke(prompt)
+    # Parse into ApiEvent
+    return parser.parse(raw.content)
+
+
+def parse_log(lines: Iterable[str]) -> List[ApiEvent]:
+    return [parse_line(line) for line in lines if line.strip()]
+
+
+def main() -> None:
+    parser_cli = argparse.ArgumentParser(description="Parse raw log into typed events")
+    parser_cli.add_argument("--log", type=Path, help="Path to a log file; if omitted, example log is used")
+    args = parser_cli.parse_args()
+
+    if args.log and args.log.exists():
+        raw_lines = args.log.read_text().splitlines()
+    else:
+        raw_lines = EXAMPLE_LOG.strip().splitlines()
+
+    events = parse_log(raw_lines)
+
+    # Print each event as JSON
+    for ev in events:
+        print(ev.model_dump_json(indent=2))
+
+    # Simple table
+    print("\nParsed events table:\n")
+    print("{:<6} {:<20} {:<6} {}".format("kind", "path", "status", "details"))
+    for ev in events:
+        if ev.kind == "ok":
+            print(f"{ev.kind:<6} {ev.path:<20} {ev.status:<6} duration={ev.duration_ms}ms")
+        else:
+            print(f"{ev.kind:<6} {ev.path:<20} {ev.status:<6} error={ev.error_message}")
+
+
+if __name__ == "__main__":
+    main()