Big refactors, performance, status images

nim.cfg

@@ -1 +1 @@
--d:ssl
+-d:ssl --threads:on

onstat.nimble

@@ -13,3 +13,4 @@ requires "nim >= 1.4.2"
 requires "https://github.com/GULPF/tiny_sqlite#8fe760d9"
 requires "karax >= 1.2.1"
 requires "cligen >= 1"
+requires "imageman >= 0.8"

src/db.nim

@@ -3,21 +3,34 @@ import options
 
 let migrations: seq[string] = @[
     """
-    CREATE TABLE sites (
+CREATE TABLE sites (
     sid INTEGER PRIMARY KEY,
     url TEXT NOT NULL
-    );
+);
 
-    CREATE TABLE reqs (
+CREATE TABLE reqs (
     rid INTEGER PRIMARY KEY,
     site INTEGER NOT NULL REFERENCES sites(sid),
     timestamp INTEGER NOT NULL,
     status INTEGER NOT NULL,
     latency INTEGER NOT NULL
-    );
+);
     """,
     """
-    CREATE INDEX req_ts_idx ON reqs (timestamp);
+CREATE INDEX req_ts_idx ON reqs (timestamp);
+    """,
+    # rolling total/successful ping and latency count
+    # rc_data_since holds the older end of the interval the counters are from
+    # this slightly horribly migrates the existing data using a hardcoded 1 week window
+    """
+ALTER TABLE sites ADD COLUMN rc_total INTEGER NOT NULL DEFAULT 0;
+ALTER TABLE sites ADD COLUMN rc_success INTEGER NOT NULL DEFAULT 0;
+ALTER TABLE sites ADD COLUMN rc_latency INTEGER NOT NULL DEFAULT 0;
+ALTER TABLE sites ADD COLUMN rc_data_since INTEGER;
+UPDATE sites SET rc_total = (SELECT COUNT(*) FROM reqs WHERE site = sid AND timestamp >= (strftime('%s') - (86400*7)) * 1000000);
+UPDATE sites SET rc_success = (SELECT SUM(status <= 0) FROM reqs WHERE site = sid AND timestamp >= (strftime('%s') - (86400*7)) * 1000000);
+UPDATE sites SET rc_latency = (SELECT SUM(latency) FROM reqs WHERE site = sid AND timestamp >= (strftime('%s') - (86400*7)) * 1000000);
+UPDATE sites SET rc_data_since = (strftime('%s') - (86400*7)) * 1000000;
     """
 ]
 

src/onstat.nim

@@ -10,8 +10,12 @@ import sugar
 import net
 import sequtils
 import strformat
-import std/exitprocs
+import strutils
 import cligen
+import imageman
+import math
+import hashes
+import tables
 
 import ./db
 
@@ -19,19 +23,6 @@ macro includeFile(x: string): string = newStrLitNode(readFile(x.strVal))
 
 const css = includeFile("./src/style.css")
 
-var threadDB {.threadvar.}: Option[DbConn]
-proc getDB(): DbConn {.gcsafe.} =
-    if isNone threadDB:
-        let x = openDatabase("./monitoring.sqlite3")
-        x.exec("PRAGMA journal_mode=WAL")
-        proc closeDB() =
-            try: close(x)
-            except: discard
-        addExitProc(closeDB)
-        when declared(onThreadDestroy): onThreadDestroy(closeDB)
-        threadDB = some x
-    get threadDB
-
 func timeToTimestamp*(t: Time): int64 = toUnix(t) * 1000000 + (nanosecond(t) div 1000)
 func timestampToTime*(ts: int64): Time = initTime(ts div 1000000, (ts mod 1000000) * 1000)
 
@@ -39,37 +30,42 @@ proc toDbValue(t: Time): DbValue = DbValue(kind: sqliteInteger, intVal: timeToTi
 proc fromDbValue(value: DbValue, T: typedesc[Time]): Time = timestampToTime(value.intVal)
 
 type
-    ResponseType = enum
+    ResponseType {.pure.} = enum
-        rtHttpTeapot = -1
+        HttpTeapot = -1
-        rtOk = 0
+        Ok = 0
-        rtHttpError = 1
+        HttpError = 1
-        rtTimeout = 2
+        Timeout = 2
-        rtFetchError = 3
+        FetchError = 3
     Response = object
         rtype: ResponseType
         latency: int64 # microseconds
     SiteStatus = object
+        id: int
         url: string
         lastPing: Time
         lastResponse: ResponseType
         lastLatency: float
         uptimePercent: float
+        averageLatency: float
+    Ctx = object
+        db: DbConn
+        dbPath: string
+        images: TableRef[int, (seq[byte], int)]
+        interval: int
 
-proc uptimeSince(sid: int, time: Time): float =
+proc fetchLatest(ctx: Ctx, row: ResultRow): Option[SiteStatus] =
-    let okPings = fromDbValue(get getDB().value("SELECT COUNT(*) FROM reqs WHERE site = ? AND status <= 0 AND timestamp >= ?", sid, time), int)
-    let totalPings = fromDbValue(get getDB().value("SELECT COUNT(*) FROM reqs WHERE site = ? AND timestamp >= ?", sid, time), int)
-    okPings / totalPings
-
-proc fetchLatest(row: ResultRow): Option[SiteStatus] =
     let weekAgo = getTime() + initTimeInterval(weeks= -1)
-    let (site, url) = row.unpack((int, string))
+    let (site, url, rollingTotalPings, rollingSuccessfulPings, rollingLatency, rollingDataSince) = row.unpack((int, string, int64, int64, int64, int64))
-    let row = getDB().one("SELECT timestamp, status, latency FROM reqs WHERE site = ? ORDER BY timestamp DESC LIMIT 1", site)
+    # work around bizarre SQLite query planner issue - it appears that if it has a literal value to compare site against it generates very fast VM code
+    # but if it has a prepared state parameter it somehow refuses to use the index
+    let row = ctx.db.one("SELECT timestamp, status, latency FROM reqs WHERE site = -1 OR site = ? ORDER BY timestamp DESC LIMIT 1", site)
     if isNone row: return none(SiteStatus)
     let (ts, status, latency) = (get row).unpack((Time, int, int))
-    some SiteStatus(url: url, lastPing: ts, lastResponse: ResponseType(status), lastLatency: float64(latency) / 1e3, uptimePercent: uptimeSince(site, weekAgo))
+    some SiteStatus(url: url, lastPing: ts, lastResponse: ResponseType(status), lastLatency: float(latency) / 1e3, id: site,
+        uptimePercent: float(rollingSuccessfulPings) / float(rollingTotalPings), averageLatency: float(rollingLatency) / float(rollingTotalPings) / 1e3)
 
-proc mainPage(): string =
+proc mainPage(ctx: Ctx): string =
-    let sites = getDB().all("SELECT * FROM sites ORDER BY sid").map(fetchLatest).filter(x => isSome x).map(x => get x)
+    let sites = ctx.db.all("SELECT * FROM sites ORDER BY sid").map(x => ctx.fetchLatest(x)).filter(x => x.isSome).map(x => x.get)
     let up = sites.filter(x => int(x.lastResponse) <= 0).len()
     let vnode = buildHtml(html()):
         head:
@@ -83,23 +79,25 @@ proc mainPage(): string =
             h2(class="title"): text &"{up}/{sites.len} up"
             for site in sites:
                 tdiv(class="card " & $site.lastResponse):
+                    tdiv(class="left"):
                         h2:
                             case site.lastResponse
-                        of rtOk: text "✓ "
+                            of ResponseType.Ok: text "✓ "
-                        of rtHttpError: text "⚠ "
+                            of ResponseType.HttpError: text "⚠ "
-                        of rtTimeout: text "✕ "
+                            of ResponseType.Timeout: text "✕ "
-                        of rtFetchError: text "✕ "
+                            of ResponseType.FetchError: text "✕ "
-                        of rtHttpTeapot: text "🫖 "
+                            of ResponseType.HttpTeapot: text "🫖 "
                             text site.url
                         tdiv: text("Last pinged " & format(site.lastPing, "HH:mm:ss dd-MM-yyyy"))
                         tdiv:
                             case site.lastResponse
-                        of rtOk: text &"Latency {site.lastLatency}ms"
+                            of ResponseType.Ok: text &"Latency {site.lastLatency}ms"
-                        of rtHttpError: text "HTTP error"
+                            of ResponseType.HttpError: text "HTTP error"
-                        of rtHttpTeapot: text &"Teapot, latency {site.lastLatency}ms"
+                            of ResponseType.HttpTeapot: text &"Teapot, latency {site.lastLatency:.5f}ms"
-                        of rtTimeout: text "Timed out"
+                            of ResponseType.Timeout: text "Timed out"
-                        of rtFetchError: text "Fetch failed"
+                            of ResponseType.FetchError: text "Fetch failed"
-                    tdiv: text &"{site.uptimePercent * 100}% up in last week"
+                        tdiv: text &"{site.uptimePercent * 100:.5f}% up, {site.averageLatency:.5f}ms latency in last week"
+                    if site.id in ctx.images: img(src= &"/vis/{site.id}", class="right", title= "&{site.url} 12-week status visualization")
             hr()
             small:
                 text "made by "
@@ -109,54 +107,158 @@ proc mainPage(): string =
                 text "."
     $vnode
 
-proc onRequest(req: Request) {.async.} =
+var imageReturnChannel: Channel[(int, seq[byte])]
+
+proc readIntoContext(ctx: Ctx) =
+    # this is a horrible workaround to avoid having to something something shared hash table
+    var available = true
+    while available:
+        let (av, data) = imageReturnChannel.tryRecv()
+        available = av
+        if available:
+            let (id, image) = data
+            ctx.images[id] = (image, image.hash)
+
+proc onRequest(ctx: Ctx): (proc(req: Request): Future[void] {.gcsafe.}) =
+    result = proc(req: Request) {.async.} =
+        readIntoContext(ctx)
         if req.reqMethod == HttpGet:
-        case req.url.path
+            var path = req.url.path
-        of "/": await req.respond(Http200, mainPage(), headers=newHttpHeaders([("Content-Type", "text/html")]))
+            if path == "/":
+                await req.respond(Http200, mainPage(ctx), headers=newHttpHeaders([("Content-Type", "text/html")]))
+            elif path.startsWith("/vis/"):
+                path.removePrefix("/vis/")
+                var id = 0
+                try:
+                    id = parseInt path
+                except:
+                    await req.respond(Http404, "not found")
+                    return
+                if id in ctx.images:
+                    let (image, hash) = ctx.images[id]
+                    let etag = &"\"{hash}\""
+                    if etag == req.headers.getOrDefault("if-none-match"):
+                        await req.respond(Http304, "")
+                    else:
+                        await req.respond(Http200, cast[string](image), headers=newHttpHeaders([
+                            ("Content-Type", "image/png"), ("ETag", etag)]))
+                else: await req.respond(Http404, "not found")
             else: await req.respond(Http404, "not found")
         else:
-        await req.respond(Http404, "not found")
+            await req.respond(Http405, "GET only")
 
-proc pollTarget(s: string): Future[Response] {.async.} =
+proc pollTarget(ctx: Ctx, s: string): Future[Response] {.async.} =
     var client = newAsyncHttpClient()
-    var x = Response(rtype: rtTimeout, latency: 0)
+    var x = Response(rtype: ResponseType.Timeout, latency: 0)
     proc doFetch() {.async.} =
         let ts = now().utc
         let res = await client.get(s)
         let latency = (now().utc - ts).inMicroseconds
-        if res.code.int == 418: x = Response(rtype: rtHttpTeapot, latency: latency)
+        if res.code.int == 418: x = Response(rtype: ResponseType.HttpTeapot, latency: latency)
-        elif res.code.is4xx or res.code.is5xx: x = Response(rtype: rtHttpError, latency: latency)
+        elif res.code.is4xx or res.code.is5xx: x = Response(rtype: ResponseType.HttpError, latency: latency)
-        else: x = Response(rtype: rtOk, latency: latency)
+        else: x = Response(rtype: ResponseType.Ok, latency: latency)
     try:
         discard await withTimeout(doFetch(), 10000)
     except:
-        x = Response(rtype: rtFetchError, latency: 0)
+        x = Response(rtype: ResponseType.FetchError, latency: 0)
     client.close()
     return x
 
-proc pollTargets() {.async.} =
+proc pollTargets(ctx: Ctx) {.async.} =
-    for row in getDB().all("SELECT * FROM sites"):
+    for row in ctx.db.all("SELECT * FROM sites"):
-        let (id, url) = row.unpack((int64, string))
+        var (id, url, rollingTotalPings, rollingSuccessfulPings, rollingLatency, rollingDataSince) = row.unpack((int64, string, int64, int64, int64, Option[Time]))
-        let res = await pollTarget(url)
+        let res = await ctx.pollTarget(url)
-        getDB().exec("INSERT INTO reqs (site, timestamp, status, latency) VALUES (?, ?, ?, ?)", id, getTime(), int(res.rtype), res.latency)
+        let threshold = getTime() + initTimeInterval(weeks= -1)
 
-proc timerCallback(fd: AsyncFD): bool =
+        # drop old data from rolling counters
-    asyncCheck pollTargets()
+        if rollingDataSince.isSome:
-    false
+            for row in ctx.db.iterate("SELECT status, latency FROM reqs WHERE timestamp >= ? AND timestamp <= ? AND site = ?", rollingDataSince.get, threshold, id):
+                let (statusRaw, latency) = row.unpack((int, int))
+                rollingTotalPings -= 1
+                rollingLatency -= latency
+                if statusRaw <= 0:
+                    rollingSuccessfulPings -= 1
+        
+        # add new data
+        rollingTotalPings += 1
+        rollingLatency += res.latency
+        if int(res.rtype) <= 0:
+            rollingSuccessfulPings += 1
+
+        ctx.db.transaction:
+            ctx.db.exec("UPDATE sites SET rc_total = ?, rc_success = ?, rc_latency = ?, rc_data_since = ? WHERE sid = ?", rollingTotalPings, rollingSuccessfulPings, rollingLatency, threshold, id)
+            ctx.db.exec("INSERT INTO reqs (site, timestamp, status, latency) VALUES (?, ?, ?, ?)", id, getTime(), int(res.rtype), res.latency)
+
+proc drawLatencyImage(db: DbConn, site: int, interval: int): seq[byte] =
+    const width = 120 * 6
+    const height = 168 * 2
+    var image = initImage[ColorRGBU](width, height)
+    var count = 0
+    var lastTs = getTime()
+    for row in db.iterate("SELECT timestamp, status, latency FROM reqs WHERE site = ? ORDER BY timestamp DESC LIMIT ?", site, width * height):
+        let (ts, statusRaw, latency) = row.unpack((Time, int, int))
+        let timeGap = lastTs - ts
+        if timeGap > initDuration(milliseconds = interval + 10000):
+            let pixels = timeGap.inMilliseconds div interval
+            for _ in 1..pixels:
+                image.data[count] = ColorRGBU([0x7Eu8, 0x1E, 0x9C])
+                count += 1
+                if count >= image.data.len: break
+        else:
+            let status = ResponseType(statusRaw)
+            case status
+            of ResponseType.HttpError:
+                image.data[count] = ColorRGBU([255u8, 127, 0])
+            of ResponseType.Timeout:
+                image.data[count] = ColorRGBU([0u8, 0, 0])
+            of ResponseType.FetchError:
+                image.data[count] = ColorRGBU([255u8, 0, 0])
+            else:
+                let latencyMultiplier = max(min(pow(10.0, 1.1) / pow(float(latency), 0.25), 1.0), 0.2)
+                image.data[count] = ColorRGBU([0u8, uint8(latencyMultiplier * 255.0), 0])
+
+            count += 1
+            if count >= image.data.len: break
+        lastTs = ts
+    writePNG(image, compression=6)
+
+proc generateImages(args: (string, int)) =
+    let (dbPath, interval) = args
+    let db = openDatabase(dbPath)
+    db.exec("PRAGMA journal_mode = WAL")
+    for row in db.all("SELECT sid FROM sites"):
+        let id = row[0].fromDbValue(int)
+        imageReturnChannel.send((id, drawLatencyImage(db, id, interval)))
+    close(db)
 
 proc run(dbPath="./monitoring.sqlite3", port=7800, interval=30000, urls: seq[string]) =
     ## Run onstat. Note that the URLs you configure will be persisted in the monitoring database. To remove them, you must manually update this.
     let database = openDatabase(dbPath)
+    database.exec("PRAGMA journal_mode = WAL")
     migrate(database)
     for url in urls:
         echo &"Adding {url}"
         database.exec("INSERT INTO sites (url) VALUES (?)", url)
-    close(database)
+
+    var ctx = Ctx(db: database, dbPath: dbPath, images: newTable[int, (seq[byte], int)](), interval: interval)
+
     echo "Starting up"
-    asyncCheck pollTargets()
+    asyncCheck pollTargets(ctx)
-    addTimer(interval, false, timerCallback)
+    imageReturnChannel.open()
+    var thread: Thread[(string, int)]
+    createThread(thread, generateImages, (dbPath, interval))
+    echo "Ready"
+    addTimer(interval, false, proc(fd: AsyncFD): bool =
+        asyncCheck pollTargets(ctx)
+        false)
+    addTimer(interval * 60, false, proc(fd: AsyncFD): bool =
+        createThread(thread, generateImages, (dbPath, interval))
+        let fut = sleepAsync(10000)
+        fut.addCallback(() => readIntoContext(ctx))
+        asyncCheck fut
+        false)
     var server = newAsyncHttpServer()
-    waitFor server.serve(Port(port), onRequest)
+    waitFor server.serve(Port(port), onRequest(ctx))
 dispatch(run, help={
     "dbPath": "path to SQLite3 database for historical data logging",
     "port": "port to serve HTTP on",

src/style.css

@@ -1,5 +1,4 @@
 body {
-    max-width: 40em;
     font-family: sans-serif;
 }
 
@@ -9,6 +8,7 @@ body {
 
 h1, h2 {
     font-weight: normal;
+    max-width: 100%;
     margin: 0;
 }
 
@@ -18,20 +18,29 @@ h1 {
 
 .card {
     margin-bottom: 1em;
+    display: flex;
+    justify-content: space-between;
+    flex-wrap: wrap;
 }
 
-.card.rtOk h2 {
+.card.Ok h2 {
     color: green;
 }
-.card.rtHttpError h2 {
+.card.HttpError h2 {
     color: orange;
 }
-.card.rtHttpTeapot h2 {
+.card.HttpTeapot h2 {
 	color: blue;
 }
-.card.rtFetchError h2 {
+.card.FetchError h2 {
     color: red;
 }
-.card.rtTimeout h2 {
+.card.Timeout h2 {
     color: red;
 }
+
+img {
+    image-rendering: pixelated;
+    -ms-interpolation-mode: nearest-neighbor;
+    image-rendering: crisp-edges;
+}