v0.2.0 (#50)

Co-authored-by: Tasnim Kabir Sadik <tksadik@omukk.dev>

Reviewed-on: wrenn/wrenn#50

pkg/service/build_stream.go

@@ -0,0 +1,72 @@
+package service
+
+import (
+	"context"
+	"encoding/json"
+	"log/slog"
+	"time"
+
+	"github.com/redis/go-redis/v9"
+)
+
+// buildStreamChannelPrefix is the Redis pub/sub channel prefix for live build
+// events. One channel per build: wrenn:build:{buildID}.
+const buildStreamChannelPrefix = "wrenn:build:"
+
+func buildStreamChannel(buildID string) string {
+	return buildStreamChannelPrefix + buildID
+}
+
+// BuildStreamEvent is one event in a build's live stream. The same struct is
+// published to Redis by the build worker and forwarded verbatim to admin
+// WebSocket clients, so its JSON shape is the wire contract for both.
+//
+// Type discriminates the payload:
+//   - "step-start":   Step, Phase, Cmd set.
+//   - "output":       Step, Data (base64 PTY bytes) set.
+//   - "step-end":     Step, Phase, Cmd, Exit, Ok, ElapsedMs set.
+//   - "build-status": Status, CurrentStep, TotalSteps, Error set.
+type BuildStreamEvent struct {
+	Type        string `json:"type"`
+	Step        int    `json:"step,omitempty"`
+	Phase       string `json:"phase,omitempty"`
+	Cmd         string `json:"cmd,omitempty"`
+	Data        string `json:"data,omitempty"` // base64-encoded PTY output bytes
+	Exit        int32  `json:"exit,omitempty"`
+	Ok          bool   `json:"ok,omitempty"`
+	ElapsedMs   int64  `json:"elapsed_ms,omitempty"`
+	Status      string `json:"status,omitempty"`
+	CurrentStep int32  `json:"current_step,omitempty"`
+	TotalSteps  int32  `json:"total_steps,omitempty"`
+	Error       string `json:"error,omitempty"`
+	T           int64  `json:"t"` // unix milliseconds, set at publish time
+}
+
+// IsTerminalBuildStatus reports whether a build status is final (the worker
+// will publish no further events for it).
+func IsTerminalBuildStatus(status string) bool {
+	switch status {
+	case "success", "failed", "cancelled":
+		return true
+	default:
+		return false
+	}
+}
+
+// publishBuildEvent fire-and-forget publishes one event to a build's Redis
+// channel. A missing/closed Redis connection only drops live events; the WS
+// client always has the DB log history to fall back on.
+func publishBuildEvent(ctx context.Context, rdb *redis.Client, buildID string, ev BuildStreamEvent) {
+	if rdb == nil {
+		return
+	}
+	ev.T = time.Now().UnixMilli()
+	payload, err := json.Marshal(ev)
+	if err != nil {
+		slog.Warn("build event marshal failed", "build_id", buildID, "error", err)
+		return
+	}
+	if err := rdb.Publish(ctx, buildStreamChannel(buildID), payload).Err(); err != nil {
+		slog.Debug("build event publish failed", "build_id", buildID, "error", err)
+	}
+}