Replace in-memory TTL cache with Redis

build.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+IMAGE="docker.adamksmith.xyz/jbod-monitor"
+
+cd "$(dirname "$0")"
+
+# Stage and commit all changes
+git add -A
+if git diff --cached --quiet; then
+    echo "No changes to commit, using HEAD"
+else
+    git commit -m "${1:-Build and push image}"
+fi
+
+SHA=$(git rev-parse --short HEAD)
+
+echo "Building ${IMAGE}:${SHA}"
+docker build -t "${IMAGE}:${SHA}" -t "${IMAGE}:latest" .
+
+echo "Pushing ${IMAGE}:${SHA}"
+docker push "${IMAGE}:${SHA}"
+docker push "${IMAGE}:latest"
+
+echo "Done: ${IMAGE}:${SHA}"

docker-compose.yml

@@ -15,3 +15,22 @@ services:
       - TZ=America/Denver
       - UVICORN_LOG_LEVEL=info
       - ZFS_USE_NSENTER=true
+      - REDIS_HOST=127.0.0.1
+      - REDIS_PORT=6379
+      - REDIS_DB=0
+      - SMART_CACHE_TTL=120
+      - SMART_POLL_INTERVAL=90
+    depends_on:
+      - redis
+
+  redis:
+    image: redis:7-alpine
+    container_name: jbod-redis
+    restart: unless-stopped
+    network_mode: host
+    volumes:
+      - redis-data:/data
+    command: redis-server --save 60 1 --loglevel warning
+
+volumes:
+  redis-data:

main.py

@@ -1,15 +1,20 @@
+import asyncio
+import json
 import logging
 import os
+from contextlib import asynccontextmanager
 from pathlib import Path
 
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
-from fastapi.responses import FileResponse
 from fastapi.staticfiles import StaticFiles
 
 from models.schemas import HealthCheck
 from routers import drives, enclosures, leds, overview
-from services.smart import sg_ses_available, smartctl_available
+from services.cache import cache_set, close_cache, init_cache, redis_available
+from services.enclosure import discover_enclosures, list_slots
+from services.smart import SMART_CACHE_TTL, _run_smartctl, sg_ses_available, smartctl_available
+from services.zfs import get_zfs_pool_map
 
 logging.basicConfig(
     level=logging.INFO,
@@ -17,10 +22,96 @@ logging.basicConfig(
 )
 logger = logging.getLogger(__name__)
 
+SMART_POLL_INTERVAL = int(os.environ.get("SMART_POLL_INTERVAL", "90"))
+
+_tool_status: dict[str, bool] = {}
+_poll_task: asyncio.Task | None = None
+
+
+async def smart_poll_loop():
+    """Pre-warm Redis with SMART data for all drives."""
+    await asyncio.sleep(2)  # let app finish starting
+    while True:
+        try:
+            # Discover all enclosure devices
+            enclosures_raw = discover_enclosures()
+            devices: set[str] = set()
+            for enc in enclosures_raw:
+                for slot in list_slots(enc["id"]):
+                    if slot["device"]:
+                        devices.add(slot["device"])
+
+            # Discover host block devices via lsblk
+            try:
+                proc = await asyncio.create_subprocess_exec(
+                    "lsblk", "-d", "-o", "NAME,TYPE", "-J",
+                    stdout=asyncio.subprocess.PIPE,
+                    stderr=asyncio.subprocess.PIPE,
+                )
+                stdout, _ = await proc.communicate()
+                if stdout:
+                    for dev in json.loads(stdout).get("blockdevices", []):
+                        if dev.get("type") == "disk":
+                            name = dev.get("name", "")
+                            if name and name not in devices:
+                                devices.add(name)
+            except Exception as e:
+                logger.warning("lsblk discovery failed in poller: %s", e)
+
+            # Poll each drive and cache result
+            for device in sorted(devices):
+                try:
+                    result = await _run_smartctl(device)
+                    await cache_set(f"jbod:smart:{device}", result, SMART_CACHE_TTL)
+                except Exception as e:
+                    logger.warning("Poll failed for %s: %s", device, e)
+
+            # Pre-warm ZFS map (bypasses cache by calling directly)
+            await get_zfs_pool_map()
+
+            logger.info("SMART poll complete: %d devices", len(devices))
+        except Exception as e:
+            logger.error("SMART poll loop error: %s", e)
+        await asyncio.sleep(SMART_POLL_INTERVAL)
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    global _poll_task
+    # Startup
+    _tool_status["smartctl"] = smartctl_available()
+    _tool_status["sg_ses"] = sg_ses_available()
+
+    if not _tool_status["smartctl"]:
+        logger.warning("smartctl not found — install smartmontools for SMART data")
+    if not _tool_status["sg_ses"]:
+        logger.warning("sg_ses not found — install sg3-utils for enclosure SES data")
+    if os.geteuid() != 0:
+        logger.warning("Not running as root — smartctl may fail on some devices")
+
+    await init_cache()
+    _tool_status["redis"] = redis_available()
+
+    if redis_available():
+        _poll_task = asyncio.create_task(smart_poll_loop())
+
+    yield
+
+    # Shutdown
+    if _poll_task is not None:
+        _poll_task.cancel()
+        try:
+            await _poll_task
+        except asyncio.CancelledError:
+            pass
+    await close_cache()
+
+
 app = FastAPI(
     title="JBOD Monitor",
     description="Drive health monitoring for JBOD enclosures",
     version="0.1.0",
+    lifespan=lifespan,
 )
 
 app.add_middleware(
@@ -35,24 +126,10 @@ app.include_router(drives.router)
 app.include_router(leds.router)
 app.include_router(overview.router)
 
-_tool_status: dict[str, bool] = {}
-
-
-@app.on_event("startup")
-async def check_dependencies():
-    _tool_status["smartctl"] = smartctl_available()
-    _tool_status["sg_ses"] = sg_ses_available()
-
-    if not _tool_status["smartctl"]:
-        logger.warning("smartctl not found — install smartmontools for SMART data")
-    if not _tool_status["sg_ses"]:
-        logger.warning("sg_ses not found — install sg3-utils for enclosure SES data")
-    if os.geteuid() != 0:
-        logger.warning("Not running as root — smartctl may fail on some devices")
-
 
 @app.get("/api/health", response_model=HealthCheck, tags=["health"])
 async def health():
+    _tool_status["redis"] = redis_available()
     return HealthCheck(status="ok", tools=_tool_status)
 
 

requirements.txt

@@ -1,3 +1,4 @@
 fastapi>=0.115.0
 uvicorn>=0.34.0
 pydantic>=2.10.0
+redis>=5.0.0

routers/drives.py

@@ -1,4 +1,4 @@
-from fastapi import APIRouter, HTTPException
+from fastapi import APIRouter, HTTPException, Response
 
 from models.schemas import DriveDetail
 from services.smart import get_smart_data
@@ -8,10 +8,10 @@ router = APIRouter(prefix="/api/drives", tags=["drives"])
 
 
 @router.get("/{device}", response_model=DriveDetail)
-async def get_drive_detail(device: str):
+async def get_drive_detail(device: str, response: Response):
     """Get SMART detail for a specific block device."""
     try:
-        data = await get_smart_data(device)
+        data, cache_hit = await get_smart_data(device)
     except ValueError as e:
         raise HTTPException(status_code=400, detail=str(e))
 
@@ -25,4 +25,6 @@ async def get_drive_detail(device: str):
         data["zfs_vdev"] = zfs_info["vdev"]
         data["zfs_state"] = zfs_info.get("state")
 
+    response.headers["X-Cache"] = "HIT" if cache_hit else "MISS"
+
     return DriveDetail(**data)

routers/overview.py

@@ -1,7 +1,7 @@
 import asyncio
 import logging
 
-from fastapi import APIRouter
+from fastapi import APIRouter, Response
 
 from models.schemas import (
     DriveHealthSummary,
@@ -22,7 +22,7 @@ router = APIRouter(prefix="/api/overview", tags=["overview"])
 
 
 @router.get("", response_model=Overview)
-async def get_overview():
+async def get_overview(response: Response):
     """Aggregate view of all enclosures, slots, and drive health."""
     enclosures_raw = discover_enclosures()
     pool_map = await get_zfs_pool_map()
@@ -53,12 +53,19 @@ async def get_overview():
         smart_results = await asyncio.gather(*smart_tasks, return_exceptions=True)
 
         smart_map: dict[str, dict] = {}
+        all_cache_hits = True
+        any_lookups = False
         for (slot_info, dev), result in zip(populated, smart_results):
             if isinstance(result, Exception):
                 logger.warning("SMART query failed for %s: %s", dev, result)
                 smart_map[dev] = {"device": dev, "smart_supported": False}
+                all_cache_hits = False
             else:
-                smart_map[dev] = result
+                data, hit = result
+                smart_map[dev] = data
+                any_lookups = True
+                if not hit:
+                    all_cache_hits = False
 
         slots_out: list[SlotWithDrive] = []
         for s in slots_raw:
@@ -170,6 +177,8 @@ async def get_overview():
                 warnings += 1
         host_drives_out.append(HostDrive(**hd))
 
+    response.headers["X-Cache"] = "HIT" if (any_lookups and all_cache_hits) else "MISS"
+
     return Overview(
         healthy=all_healthy and errors == 0,
         drive_count=total_drives,

services/cache.py

@@ -1,29 +1,62 @@
-import time
+import json
+import logging
+import os
 from typing import Any
 
+import redis.asyncio as redis
 
-class TTLCache:
-    """Simple in-memory TTL cache."""
+logger = logging.getLogger(__name__)
 
-    def __init__(self, ttl_seconds: int = 60):
-        self._ttl = ttl_seconds
-        self._store: dict[str, tuple[float, Any]] = {}
+_redis: redis.Redis | None = None
 
-    def get(self, key: str) -> Any | None:
-        entry = self._store.get(key)
-        if entry is None:
+
+async def init_cache() -> None:
+    """Create Redis connection from environment variables."""
+    global _redis
+    host = os.environ.get("REDIS_HOST", "localhost")
+    port = int(os.environ.get("REDIS_PORT", "6379"))
+    db = int(os.environ.get("REDIS_DB", "0"))
+    try:
+        _redis = redis.Redis(host=host, port=port, db=db, decode_responses=True)
+        await _redis.ping()
+        logger.info("Redis connected at %s:%d/%d", host, port, db)
+    except Exception as e:
+        logger.warning("Redis connection failed: %s — running without cache", e)
+        _redis = None
+
+
+async def close_cache() -> None:
+    """Close Redis connection."""
+    global _redis
+    if _redis is not None:
+        await _redis.aclose()
+        _redis = None
+
+
+def redis_available() -> bool:
+    """Return whether Redis connection is live."""
+    return _redis is not None
+
+
+async def cache_get(key: str) -> Any | None:
+    """GET key from Redis, return deserialized value or None on miss/error."""
+    if _redis is None:
         return None
-        ts, value = entry
-        if time.monotonic() - ts > self._ttl:
-            del self._store[key]
+    try:
+        raw = await _redis.get(key)
+        if raw is None:
+            return None
+        return json.loads(raw)
+    except Exception as e:
+        logger.warning("Redis GET %s failed: %s", key, e)
         return None
-        return value
-
-    def set(self, key: str, value: Any) -> None:
-        self._store[key] = (time.monotonic(), value)
-
-    def clear(self) -> None:
-        self._store.clear()
 
 
-smart_cache = TTLCache(ttl_seconds=60)
+async def cache_set(key: str, value: Any, ttl: int = 120) -> None:
+    """SET key in Redis with expiry, silently catches errors."""
+    if _redis is None:
+        return
+    try:
+        await _redis.set(key, json.dumps(value), ex=ttl)
+    except Exception as e:
+        logger.warning("Redis SET %s failed: %s", key, e)

services/host.py

@@ -65,12 +65,14 @@ async def get_host_drives() -> list[dict]:
     smart_results = await asyncio.gather(*smart_tasks, return_exceptions=True)
 
     results: list[dict] = []
-    for dev_info, smart in zip(host_devices, smart_results):
+    for dev_info, smart_result in zip(host_devices, smart_results):
         name = dev_info["name"]
 
-        if isinstance(smart, Exception):
-            logger.warning("SMART query failed for host drive %s: %s", name, smart)
+        if isinstance(smart_result, Exception):
+            logger.warning("SMART query failed for host drive %s: %s", name, smart_result)
             smart = {"device": name, "smart_supported": False}
+        else:
+            smart, _ = smart_result
 
         # Compute health_status (same logic as overview.py)
         healthy = smart.get("smart_healthy")

services/smart.py

@@ -1,10 +1,11 @@
 import asyncio
 import json
 import logging
+import os
 import re
 import shutil
 
-from services.cache import smart_cache
+from services.cache import cache_get, cache_set
 
 logger = logging.getLogger(__name__)
 
@@ -17,6 +18,8 @@ ATTR_PENDING = 197
 ATTR_UNCORRECTABLE = 198
 ATTR_WEAR_LEVELING = 177  # SSD wear leveling
 
+SMART_CACHE_TTL = int(os.environ.get("SMART_CACHE_TTL", "120"))
+
 
 def smartctl_available() -> bool:
     return shutil.which("smartctl") is not None
@@ -26,19 +29,22 @@ def sg_ses_available() -> bool:
     return shutil.which("sg_ses") is not None
 
 
-async def get_smart_data(device: str) -> dict:
-    """Run smartctl -a -j against a device, with caching."""
+async def get_smart_data(device: str) -> tuple[dict, bool]:
+    """Run smartctl -a -j against a device, with caching.
+
+    Returns (data, cache_hit) tuple.
+    """
     # Sanitize device name: only allow alphanumeric and hyphens
     if not re.match(r"^[a-zA-Z0-9\-]+$", device):
         raise ValueError(f"Invalid device name: {device}")
 
-    cached = smart_cache.get(device)
+    cached = await cache_get(f"jbod:smart:{device}")
     if cached is not None:
-        return cached
+        return (cached, True)
 
     result = await _run_smartctl(device)
-    smart_cache.set(device, result)
-    return result
+    await cache_set(f"jbod:smart:{device}", result, SMART_CACHE_TTL)
+    return (result, False)
 
 
 async def _run_smartctl(device: str) -> dict:

services/zfs.py

@@ -4,11 +4,15 @@ import logging
 import re
 from pathlib import Path
 
+from services.cache import cache_get, cache_set
+
 logger = logging.getLogger(__name__)
 
 # Allow overriding the zpool binary path via env (for bind-mounted host tools)
 ZPOOL_BIN = os.environ.get("ZPOOL_BIN", "zpool")
 
+ZFS_CACHE_TTL = 300
+
 
 async def get_zfs_pool_map() -> dict[str, dict]:
     """Return a dict mapping device names to ZFS pool and vdev info.
@@ -16,6 +20,10 @@ async def get_zfs_pool_map() -> dict[str, dict]:
     e.g. {"sda": {"pool": "tank", "vdev": "raidz2-0"},
           "sdb": {"pool": "fast", "vdev": "mirror-0"}}
     """
+    cached = await cache_get("jbod:zfs_map")
+    if cached is not None:
+        return cached
+
     pool_map = {}
     try:
         # When running in a container with pid:host, use nsenter to run
@@ -94,6 +102,8 @@ async def get_zfs_pool_map() -> dict[str, dict]:
                     pass
     except FileNotFoundError:
         logger.debug("zpool not available")
+
+    await cache_set("jbod:zfs_map", pool_map, ZFS_CACHE_TTL)
     return pool_map