ns8-backup-monitor/ns8_backup_monitor/notifier.py

#!/usr/bin/env python3
"""
notifier.py - Sends a single classified notification email via ns8-sendmail.

Delivery strategy:
  1. ns8-sendmail -t   (uses NS8 configured relay - preferred)
  2. sendmail -t       (fallback if ns8-sendmail not found)

No SMTP configuration needed: ns8-sendmail already knows the relay.
"""

import logging
import shutil
import subprocess
from datetime import datetime, timezone
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from typing import Optional

log = logging.getLogger(__name__)

OUTCOME_LABEL = {
    "SUCCESS": "OK",
    "PARTIAL": "WARNING",
    "REPO_FAILURE": "CRITICAL",
}

OUTCOME_COLOR = {
    "SUCCESS": "#2e7d32",
    "PARTIAL": "#e65100",
    "REPO_FAILURE": "#b71c1c",
}


def _sendmail_binary() -> str:
    """Return the path to ns8-sendmail, falling back to sendmail."""
    for cmd in ("ns8-sendmail", "sendmail"):
        path = shutil.which(cmd)
        if path:
            return path
    raise FileNotFoundError("Neither ns8-sendmail nor sendmail found in PATH")


def _build_text(correlation: dict, repo_status: Optional[dict]) -> str:
    outcome = correlation["outcome"]
    lines = [
        f"NS8 Backup Monitor - {OUTCOME_LABEL[outcome]}: {outcome}",
        f"Time: {datetime.now(timezone.utc).isoformat()}",
        f"Plans checked: {', '.join(correlation.get('backup_ids', []))}",
        f"Modules: {correlation['succeeded']} OK / {correlation['failed']} FAILED / {correlation['total']} total",
        "",
    ]

    if correlation["failed_modules"]:
        lines.append("Failed modules:")
        for m in correlation["failed_modules"]:
            lines.append(f"  - [{m['module_id']}] backup_id={m['backup_id']}: {m.get('error', 'unknown error')}")
        lines.append("")

    if repo_status:
        lines.append("Repository check:")
        for dest in repo_status.get("destinations", []):
            lines.append(f"  - [{dest['repo_id']}] {dest['status']}: {dest.get('error', '')}")
        if repo_status.get("note"):
            lines.append(f"  NOTE: {repo_status['note']}")
        lines.append("")

    if correlation.get("note"):
        lines.append(f"Note: {correlation['note']}")

    return "\n".join(lines)


def _build_html(correlation: dict, repo_status: Optional[dict]) -> str:
    outcome = correlation["outcome"]
    color = OUTCOME_COLOR[outcome]
    label = OUTCOME_LABEL[outcome]
    ts = datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M UTC")
    plan_ids = ", ".join(correlation.get("backup_ids", [])) or "N/A"

    rows = ""
    for m in correlation.get("modules", []):
        bg = "#e8f5e9" if m["result"] == "success" else "#ffebee"
        icon = "✓" if m["result"] == "success" else "✗"
        rows += (
            f'<tr style="background:{bg}">'
            f'<td style="padding:4px 8px">{icon}</td>'
            f'<td style="padding:4px 8px">{m["module_id"]}</td>'
            f'<td style="padding:4px 8px">{m["backup_id"]}</td>'
            f'<td style="padding:4px 8px">{m.get("timestamp", "")}</td>'
            f'<td style="padding:4px 8px">{m.get("error", "") or ""}</td>'
            '</tr>'
        )

    repo_section = ""
    if repo_status:
        repo_rows = ""
        for dest in repo_status.get("destinations", []):
            bg = "#e8f5e9" if dest["status"] == "OK" else "#ffebee"
            repo_rows += (
                f'<tr style="background:{bg}">'
                f'<td style="padding:4px 8px">{dest["repo_id"]}</td>'
                f'<td style="padding:4px 8px"><b>{dest["status"]}</b></td>'
                f'<td style="padding:4px 8px">{dest.get("error", "")}</td>'
                '</tr>'
            )
        if repo_rows:
            repo_section = f"""
            <h3 style="margin-top:24px">Repository check</h3>
            <table border="1" cellspacing="0" cellpadding="0" style="border-collapse:collapse;font-size:13px;width:100%">
              <thead><tr style="background:#f5f5f5">
                <th style="padding:4px 8px">Repo ID</th>
                <th style="padding:4px 8px">Status</th>
                <th style="padding:4px 8px">Detail</th>
              </tr></thead>
              <tbody>{repo_rows}</tbody>
            </table>
            """
        if repo_status.get("note"):
            repo_section += f'<p style="color:#777;font-size:12px">{repo_status["note"]}</p>'

    return f"""
    <html><body style="font-family:monospace;font-size:14px;max-width:800px;margin:auto">
      <div style="background:{color};color:#fff;padding:16px 20px;border-radius:6px 6px 0 0">
        <b>NS8 Backup Monitor &mdash; {label}: {outcome}</b><br>
        <small>{ts} &bull; Plans: {plan_ids}</small>
      </div>
      <div style="border:1px solid #ddd;border-top:none;padding:16px 20px;border-radius:0 0 6px 6px">
        <p>
          <b>{correlation['succeeded']}</b> module(s) OK &nbsp;|&nbsp;
          <b>{correlation['failed']}</b> FAILED &nbsp;|&nbsp;
          <b>{correlation['total']}</b> total
        </p>
        <table border="1" cellspacing="0" cellpadding="0" style="border-collapse:collapse;font-size:13px;width:100%">
          <thead><tr style="background:#f5f5f5">
            <th style="padding:4px 8px"></th>
            <th style="padding:4px 8px">Module</th>
            <th style="padding:4px 8px">Backup ID</th>
            <th style="padding:4px 8px">Timestamp</th>
            <th style="padding:4px 8px">Error</th>
          </tr></thead>
          <tbody>{rows}</tbody>
        </table>
        {repo_section}
      </div>
    </body></html>
    """


def send_notification(
    config: dict,
    alerts: list,
    correlation: dict,
    repo_status: Optional[dict] = None
):
    outcome = correlation["outcome"]
    mail_cfg = config.get("mail", {})
    subject_prefix = mail_cfg.get("subject_prefix", "[NS8 Backup]")
    subject = (
        f"{subject_prefix} {OUTCOME_LABEL[outcome]}: {outcome} - "
        f"{datetime.now(timezone.utc).strftime('%Y-%m-%d')}"
    )

    mail_to = mail_cfg.get("to", [])
    if not mail_to:
        log.error("No mail.to recipients configured - cannot send notification")
        return

    mail_from = mail_cfg.get("from", "")

    text_body = _build_text(correlation, repo_status)
    html_body = _build_html(correlation, repo_status)

    msg = MIMEMultipart("alternative")
    msg["Subject"] = subject
    msg["To"] = ", ".join(mail_to)
    if mail_from:
        msg["From"] = mail_from
    msg.attach(MIMEText(text_body, "plain"))
    msg.attach(MIMEText(html_body, "html"))

    try:
        binary = _sendmail_binary()
    except FileNotFoundError as e:
        log.error(str(e))
        return

    try:
        proc = subprocess.run(
            [binary, "-t"],
            input=msg.as_bytes(),
            capture_output=True,
            timeout=30,
        )
        if proc.returncode != 0:
            log.error(
                f"ns8-sendmail exited {proc.returncode}: {proc.stderr.decode().strip()}"
            )
        else:
            log.info(f"Notification sent via {binary}: {subject} -> {mail_to}")
    except subprocess.TimeoutExpired:
        log.error(f"ns8-sendmail timed out after 30s")
    except Exception as e:
        log.error(f"Failed to invoke {binary}: {e}")