v0.4.1

internal/rrd/rrd.go

@@ -5,53 +5,44 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"math"
 	"os"
 	"os/exec"
-	"path/filepath"
 	"strconv"
 	"strings"
 	"sync"
-	"time"
 )
 
 type Manager struct {
-	Tool     string
-	Path     string
-	GraphDir string
-	mu       sync.Mutex
+	Tool string
+	Path string
+	mu   sync.Mutex
 }
 
-// Graph colors mirror the dashboard's theme tokens (internal/web/assets/app.css)
-// so rendered PNGs sit visually in place inside the panel cards. Each range
-// is rendered twice (dark + light) so the client can pick the variant that
-// matches the active site theme without round-tripping through rrdtool.
-const (
-	graphColorPanel      = "#181c19" // --panel (dark)
-	graphColorField      = "#121713" // --field (dark plot canvas)
-	graphColorLine       = "#313832" // --line (dark minor grid)
-	graphColorLine2      = "#485149" // --line2 (dark axis / major grid)
-	graphColorText       = "#edf0ecCC"
-	graphColorAccent     = "#8fb9a4" // --accent (dark)
-	graphColorAccentFill = "#8fb9a43d"
-
-	graphLightColorPanel      = "#ffffff" // --panel (light)
-	graphLightColorField      = "#f7f8f6" // --panel2 (light plot canvas)
-	graphLightColorLine       = "#cbd2cb" // --line (light minor grid)
-	graphLightColorLine2      = "#aeb8af" // --line2 (light axis / major grid)
-	graphLightColorText       = "#202622CC"
-	graphLightColorAccent     = "#507b67" // --accent (light)
-	graphLightColorAccentFill = "#507b673d"
-)
-
-type Range struct{ Key, Start, Title string }
+// Range describes one of the dashboard's graph time windows. CF is the RRD
+// consolidation function to fetch with: "LAST" for the windows covered by
+// the full-resolution 1x60s RRA (see packaging/ts3monolith-init-rrd), and
+// "AVERAGE" for the longer windows that only exist in the coarser,
+// pre-averaged RRAs -- asking those for LAST would silently return nothing
+// older than the full-resolution RRA's ~75h span.
+type Range struct{ Key, Start, Title, CF string }
 
 var Ranges = []Range{
-	{"hour", "-12h", "Ostatnie 12 godzin"},
-	{"day", "-24h", "Ostatnie 24 godziny"},
-	{"72h", "-72h", "Ostatnie 72 godziny"},
-	{"week", "-1w", "Ostatni tydzień"},
-	{"month", "-1m", "Ostatni miesiąc"},
-	{"year", "-1y", "Ostatni rok"},
+	{"hour", "-12h", "Ostatnie 12 godzin", "LAST"},
+	{"day", "-24h", "Ostatnie 24 godziny", "LAST"},
+	{"72h", "-72h", "Ostatnie 72 godziny", "LAST"},
+	{"week", "-1w", "Ostatni tydzień", "AVERAGE"},
+	{"month", "-1m", "Ostatni miesiąc", "AVERAGE"},
+	{"year", "-1y", "Ostatni rok", "AVERAGE"},
+}
+
+func rangeByKey(key string) *Range {
+	for i := range Ranges {
+		if Ranges[i].Key == key {
+			return &Ranges[i]
+		}
+	}
+	return nil
 }
 
 func (m *Manager) Validate() error {
@@ -61,7 +52,7 @@ func (m *Manager) Validate() error {
 	if st, err := os.Stat(m.Path); err != nil || st.IsDir() {
 		return fmt.Errorf("RRD file unavailable: %s", m.Path)
 	}
-	return os.MkdirAll(m.GraphDir, 0750)
+	return nil
 }
 
 func (m *Manager) Update(ctx context.Context, online int) error {
@@ -99,81 +90,164 @@ func (m *Manager) Last(ctx context.Context) (int, error) {
 	return int(f + 0.5), err
 }
 
-func (m *Manager) Graph(ctx context.Context, key, theme string) (string, error) {
-	var rg *Range
-	for i := range Ranges {
-		if Ranges[i].Key == key {
-			rg = &Ranges[i]
-			break
-		}
-	}
+// Point is one JSON-serializable RRD sample. V is nil when the RRA has no
+// data for that timestamp (rrdtool reports it as "nan"), which the
+// front-end renders as a gap in the line rather than a drop to zero.
+type Point struct {
+	T int64    `json:"t"`
+	V *float64 `json:"v"`
+}
+
+// GraphData is the JSON payload served at GET /stats/graph/{key}. Aktualnie
+// / Średnio / Maks. are computed here (over the fetched window) so the
+// front-end doesn't need to re-derive them, mirroring what the old
+// rrdtool-rendered PNGs printed under the graph via GPRINT.
+type GraphData struct {
+	Key     string   `json:"key"`
+	Title   string   `json:"title"`
+	Step    int64    `json:"step"`
+	Points  []Point  `json:"points"`
+	Current *float64 `json:"current"`
+	Average *float64 `json:"average"`
+	Max     *float64 `json:"max"`
+}
+
+// maxChartPoints caps how many samples Fetch returns per range. The raw
+// RRA rows can be far denser than any chart will ever display pixel-for-
+// pixel (72h at the full-resolution 60s RRA is 4320 rows), which both
+// bloats the JSON response for no visual benefit and, rendered 1:1,
+// produces a dense, spiky look where many adjacent ups/downs alias into
+// what looks like noise. downsample buckets the raw series down to this
+// many points (each bucket averaged, like an RRD AVERAGE RRA does) before
+// it's returned, independent of any particular browser's viewport.
+const maxChartPoints = 450
+
+// Fetch reads the samples for one graph range directly from the RRD file
+// via `rrdtool fetch`, for the front-end to render client-side. This
+// replaces the previous approach of shelling out to `rrdtool graph` to
+// render a PNG per theme: fetch returns a small JSON array instead of an
+// image, so the browser can draw it (and redraw it on theme change or
+// resize) without a round-trip, and it never produces the server-side-
+// rendering quirks (fixed margins, fixed colors) that made the PNGs
+// awkward to fit responsively.
+func (m *Manager) Fetch(ctx context.Context, key string) (GraphData, error) {
+	rg := rangeByKey(key)
 	if rg == nil {
-		return "", errors.New("unknown graph range")
+		return GraphData{}, errors.New("unknown graph range")
 	}
-	if err := os.MkdirAll(m.GraphDir, 0750); err != nil {
-		return "", err
+	data, err := m.fetchCF(ctx, rg, rg.CF)
+	if err != nil && rg.CF != "LAST" {
+		// An RRD file that predates packaging/ts3monolith-init-rrd (e.g. an
+		// archived database carried over from the old PHP app, as this
+		// project's README tells operators to do) may not have an
+		// AVERAGE-consolidated RRA at all. LAST is the one CF every range
+		// used exclusively before this JSON rewrite (see git history), so
+		// it's guaranteed to exist -- fall back to it rather than leaving
+		// week/month/year permanently broken against such a file.
+		data, err = m.fetchCF(ctx, rg, "LAST")
 	}
+	return data, err
+}
 
-	panel, field, line, line2, text, accent, accentFill := graphColorPanel, graphColorField, graphColorLine, graphColorLine2, graphColorText, graphColorAccent, graphColorAccentFill
-	suffix := ""
-	if theme == "light" {
-		panel, field, line, line2, text, accent, accentFill = graphLightColorPanel, graphLightColorField, graphLightColorLine, graphLightColorLine2, graphLightColorText, graphLightColorAccent, graphLightColorAccentFill
-		suffix = "-light"
-	}
-	out := filepath.Join(m.GraphDir, key+suffix+".png")
-
-	m.mu.Lock()
-	defer m.mu.Unlock()
-	if st, err := os.Stat(out); err == nil && time.Since(st.ModTime()) < 55*time.Second {
-		return out, nil
-	}
-
-	def := "DEF:online=" + m.Path + ":online:LAST"
-	watermark := "linuxiarz.pl  ·  " + time.Now().Format("2006-01-02 15:04")
-	args := []string{
-		"graph", out,
-		"--imgformat", "PNG",
-		"--start", rg.Start, "--end", "now",
-		// By default rrdtool's --width/--height size only the plot canvas;
-		// the title, legend rows and axis-label margins then pad the final
-		// PNG to something larger and variable (depends on title/legend
-		// text length). --full-size-mode makes --width/--height the exact
-		// *total* image size instead, so the PNG is always precisely
-		// 1200x320 -- matching the CSS aspect-ratio on the <img> exactly,
-		// with no letterboxing from a size mismatch.
-		"--full-size-mode",
-		"--width", "1200", "--height", "320",
-		"--lower-limit", "0", "--alt-autoscale-max", "--rigid",
-		"--slope-mode",
-		"--title", rg.Title,
-		"--vertical-label", "użytkownicy",
-		"--border", "0",
-		"--color", "BACK" + panel,
-		"--color", "CANVAS" + field,
-		"--color", "FONT" + text,
-		"--color", "AXIS" + line2,
-		"--color", "ARROW" + line2,
-		"--color", "GRID" + line,
-		"--color", "MGRID" + line2,
-		"--color", "FRAME" + panel,
-		"--font", "DEFAULT:0:",
-		"--font", "TITLE:13:",
-		"--font", "AXIS:9:",
-		"--font", "LEGEND:10:",
-		"--font", "UNIT:9:",
-		"--watermark", watermark,
-		def,
-		"AREA:online" + accentFill,
-		"LINE2:online" + accent + ":Online",
-		"GPRINT:online:LAST:Aktualnie\\: %4.0lf",
-		"GPRINT:online:AVERAGE:Średnio\\: %4.0lf",
-		"GPRINT:online:MAX:Maks.\\: %4.0lf\\n",
-	}
-	cmd := exec.CommandContext(ctx, m.Tool, args...)
+func (m *Manager) fetchCF(ctx context.Context, rg *Range, cf string) (GraphData, error) {
+	cmd := exec.CommandContext(ctx, m.Tool, "fetch", m.Path, cf, "--start", rg.Start, "--end", "now")
 	var stderr bytes.Buffer
 	cmd.Stderr = &stderr
-	if err := cmd.Run(); err != nil {
-		return "", fmt.Errorf("rrd graph: %w: %s", err, strings.TrimSpace(stderr.String()))
+	out, err := cmd.Output()
+	if err != nil {
+		return GraphData{}, fmt.Errorf("rrd fetch: %w: %s", err, strings.TrimSpace(stderr.String()))
 	}
-	return out, nil
+
+	data := GraphData{Key: rg.Key, Title: rg.Title}
+	var raw []Point
+	var sum float64
+	var n int
+	var prevT int64 = -1
+
+	for _, line := range strings.Split(string(out), "\n") {
+		line = strings.TrimSpace(line)
+		if line == "" {
+			continue
+		}
+		idx := strings.IndexByte(line, ':')
+		if idx < 0 {
+			continue // header line, e.g. "          online"
+		}
+		ts, err := strconv.ParseInt(strings.TrimSpace(line[:idx]), 10, 64)
+		if err != nil {
+			continue // not a data row
+		}
+		pt := Point{T: ts}
+		if f, err := strconv.ParseFloat(strings.TrimSpace(line[idx+1:]), 64); err == nil && !math.IsNaN(f) {
+			v := f
+			pt.V = &v
+			sum += f
+			n++
+			if data.Max == nil || f > *data.Max {
+				mx := f
+				data.Max = &mx
+			}
+			cur := f
+			data.Current = &cur // last valid sample wins
+		}
+		if prevT >= 0 {
+			data.Step = ts - prevT
+		}
+		prevT = ts
+		raw = append(raw, pt)
+	}
+	if n > 0 {
+		avg := sum / float64(n)
+		data.Average = &avg
+	}
+	// Current/Average/Max above are computed from the full raw series, not
+	// diluted by downsampling; only the plotted points themselves shrink.
+	data.Points = downsample(raw, maxChartPoints)
+	if len(data.Points) > 1 {
+		data.Step = data.Points[1].T - data.Points[0].T
+	}
+	return data, nil
+}
+
+// downsample buckets points down to at most target entries. Each bucket's
+// value is the average of its non-null samples (nil if the bucket has
+// none), and its timestamp is the last raw timestamp in the bucket -- the
+// same shape as an RRD AVERAGE RRA, so long ranges read as a smooth trend
+// instead of a wall of raw per-minute noise. Points already at or under
+// the target are returned unchanged.
+func downsample(points []Point, target int) []Point {
+	if target <= 0 || len(points) <= target {
+		return points
+	}
+	bucket := float64(len(points)) / float64(target)
+	out := make([]Point, 0, target)
+	for i := 0; i < target; i++ {
+		start := int(float64(i) * bucket)
+		end := int(float64(i+1) * bucket)
+		if end <= start {
+			end = start + 1
+		}
+		if end > len(points) {
+			end = len(points)
+		}
+		if start >= end {
+			break
+		}
+		var sum float64
+		var n int
+		t := points[end-1].T
+		for _, p := range points[start:end] {
+			if p.V != nil {
+				sum += *p.V
+				n++
+			}
+		}
+		pt := Point{T: t}
+		if n > 0 {
+			avg := sum / float64(n)
+			pt.V = &avg
+		}
+		out = append(out, pt)
+	}
+	return out
 }