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scribe/scraibe/summarizer.py
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Improve summary prompt, add markdown-to-DOCX styling, and add cover pages
- Configurable summary prompts via ENV or file; stronger default prompt.
- New docx_styles.py: converts markdown (headings, bullets, bold/italic) to DOCX.
- Updated create_summary_docx to use markdown-aware styling.
- New docx_cover.py: reusable cover page for transcript and summary.
- Cover pages enabled when COVER_PAGE_ENABLED=true.
2026-06-19 17:16:46 +00:00

295 lines
10 KiB
Python

"""
Summarizer Module
-----------------
Provides a client to summarize long transcripts via an LLM endpoint.
Behavior:
- Chunks transcript into 10,240-character segments.
- Summarizes each chunk.
- Summarizes the summaries into a final, detailed summary.
Environment Variables:
- SUMMARIZER_API_URL: (required) Base URL of the LLM API (e.g., http://localhost:8080)
- SUMMARIZER_API_KEY: (optional) API key, if required
- SUMMARIZER_MODEL: (optional) Model name (e.g., llama-3.1-8b-instruct)
"""
import os
import json
import logging
from typing import Optional
import httpx
logger = logging.getLogger("scraibe.summarizer")
class SummarizerError(Exception):
"""Raised when the summarization API call fails."""
pass
class SummarizerClient:
"""
HTTP client for an OpenAI-compatible chat completions endpoint.
Used to summarize long transcripts in chunks.
"""
CHUNK_SIZE = 10_240 # characters per chunk
def __init__(
self,
api_url: Optional[str] = None,
api_key: Optional[str] = None,
model: Optional[str] = None,
timeout: float = 3600.0,
):
self.api_url = (api_url or os.getenv("SUMMARIZER_API_URL")).strip().rstrip("/")
self.api_key = api_key or os.getenv("SUMMARIZER_API_KEY") or None
self.model = model or os.getenv("SUMMARIZER_MODEL") or "llama-3.1-8b-instruct"
self.timeout = timeout
if not self.api_url:
raise SummarizerError(
"SUMMARIZER_API_URL is not set. "
"Provide the summarization LLM URL via environment or constructor."
)
logger.info(
"Initializing SummarizerClient: url=%s model=%s",
self.api_url,
self.model,
)
self._client = httpx.Client(
base_url=self.api_url,
timeout=self.timeout,
follow_redirects=True,
)
def close(self):
self._client.close()
def __del__(self):
try:
self._client.close()
except Exception:
pass
def summarize_transcript(self, transcript: str) -> str:
"""
Summarize a (possibly very long) transcript.
Strategy:
- Split transcript into chunks of CHUNK_SIZE characters.
- Generate a detailed summary for each chunk.
- Combine all chunk summaries and generate a final, concise but thorough summary.
The final summary should make it clear:
- What was discussed
- Main issues
- Outcomes / decisions
- Next steps / action items
"""
if not transcript.strip():
logger.warning("Empty transcript provided to summarize_transcript.")
return "No transcript provided to summarize."
logger.info(
"Starting summarization for transcript length=%d chars",
len(transcript),
)
# 1) Chunk the transcript
chunks = self._chunk_text(transcript)
logger.info("Split transcript into %d chunks.", len(chunks))
# 2) Summarize each chunk
chunk_summaries = []
for i, chunk in enumerate(chunks):
logger.info(
"Summarizing chunk %d/%d (length=%d)",
i + 1,
len(chunks),
len(chunk),
)
summary = self._summarize_chunk(chunk, i, len(chunks))
chunk_summaries.append(summary)
# 3) Combine and summarize summaries
combined = "\n\n".join(chunk_summaries)
logger.info(
"Combining %d chunk summaries (total length=%d) for final summary.",
len(chunk_summaries),
len(combined),
)
final_summary = self._summarize_combined(combined)
logger.info("Summarization completed.")
return final_summary
def _chunk_text(self, text: str) -> list[str]:
"""Split text into chunks of CHUNK_SIZE characters."""
chunks = []
start = 0
while start < len(text):
end = start + self.CHUNK_SIZE
if end >= len(text):
chunks.append(text[start:])
break
# Try to break at a reasonable boundary (newline or space)
break_pos = text.rfind("\n", start, end)
if break_pos == -1:
break_pos = text.rfind(" ", start, end)
if break_pos == -1 or break_pos <= start:
break_pos = end
chunks.append(text[start:break_pos].strip())
start = break_pos
return chunks
def _load_summary_prompt(self, role: str) -> str:
"""
Load summary prompt for the given role: 'chunk' or 'combined'.
Priority:
1) SUMMARY_PROMPT_{ROLE} (env)
2) SUMMARY_PROMPT_FILE (env) with [chunk] / [combined] sections
3) Built-in default prompt
"""
role_upper = role.upper()
# 1) Direct env var: SUMMARY_PROMPT_CHUNK / SUMMARY_PROMPT_COMBINED
env_key = f"SUMMARY_PROMPT_{role_upper}"
env_prompt = (os.getenv(env_key) or "").strip()
if env_prompt:
return env_prompt
# 2) File-based prompt with sections
prompt_file = (os.getenv("SUMMARY_PROMPT_FILE") or "").strip()
if prompt_file and os.path.exists(prompt_file):
try:
with open(prompt_file, "r", encoding="utf-8") as f:
content = f.read()
# Simple section parser: [chunk], [combined]
import re
pattern = re.compile(
r"\[" + role + r"\]\s*\n(.*?)(?=\n\[|$)",
re.DOTALL,
)
m = pattern.search(content)
if m:
text = m.group(1).strip()
if text:
return text
except Exception as e:
logger.warning("Failed to load SUMMARY_PROMPT_FILE for %s: %s", role, e)
# 3) Default prompts
if role == "chunk":
return (
"You are an expert legal and business meeting summarizer. "
"You will receive a segment of a longer transcript. "
"Provide a detailed, structured summary of this segment, focusing on: "
"- Topics discussed\n"
"- Key points and arguments\n"
"- Decisions and agreements\n"
"- Action items and responsibilities\n"
"- Any risks, conflicts, or open issues\n\n"
"Be concise but complete. Use bullet points where helpful. "
"Do not add information that is not present in the transcript."
)
else:
return (
"You are an expert legal and business meeting summarizer. "
"You will receive several intermediate summaries of a longer conversation. "
"Produce a single, comprehensive summary that makes it clear: "
"- The overall purpose and context of the discussion\n"
"- The main issues and topics addressed\n"
"- Key arguments and positions (briefly)\n"
"- Decisions and outcomes\n"
"- Action items, responsibilities, and next steps\n"
"- Any unresolved issues or risks\n\n"
"The summary should be detailed enough that a reader who was not present "
"can understand what happened and what is expected going forward. "
"Use clear, concise language and bullet points where appropriate. "
"Use markdown formatting (headings, lists, bold) to structure the summary."
)
def _summarize_chunk(self, chunk: str, index: int, total: int) -> str:
system_prompt = self._load_summary_prompt("chunk")
user_prompt = (
f"This is segment {index + 1} of {total} from a longer conversation.\n\n"
f"{chunk}"
)
return self._chat_completion(system_prompt, user_prompt)
def _summarize_combined(self, combined_summaries: str) -> str:
system_prompt = self._load_summary_prompt("combined")
user_prompt = (
"Here are the intermediate summaries from different parts of the same conversation:\n\n"
f"{combined_summaries}"
)
return self._chat_completion(system_prompt, user_prompt)
def _chat_completion(self, system_prompt: str, user_prompt: str) -> str:
"""
Call OpenAI-compatible /v1/chat/completions endpoint.
"""
payload = {
"model": self.model,
"messages": [
{"role": "system", "content": system_prompt},
{"role": "user", "content": user_prompt},
],
"temperature": 0.3,
}
headers = {
"Content-Type": "application/json",
}
if self.api_key:
headers["Authorization"] = f"Bearer {self.api_key}"
logger.info("Calling summarizer endpoint: /v1/chat/completions")
resp = self._client.post(
"/v1/chat/completions",
json=payload,
headers=headers,
)
logger.info("Summarizer response status: %d", resp.status_code)
if resp.status_code >= 400:
logger.error("Summarizer error response: %s", resp.text)
raise SummarizerError(
f"Summarizer API error {resp.status_code}: {resp.text}"
)
try:
data = resp.json()
except json.JSONDecodeError:
logger.error("Failed to parse summarizer response as JSON.")
raise SummarizerError(
"Failed to parse summarizer response as JSON."
)
# Extract assistant message
try:
content = data["choices"][0]["message"]["content"]
return content.strip()
except (KeyError, IndexError, TypeError):
logger.error(
"Unexpected summarizer response format: %s",
json.dumps(data, indent=2),
)
raise SummarizerError(
"Unexpected summarizer response format: "
f"{json.dumps(data, indent=2)}"
)