feat: publish standalone worker

Separate worker packaging and service lifecycle from the control plane.

app/models/task.go

@@ -0,0 +1,145 @@
+package models
+
+import (
+	"time"
+
+	"gorm.io/datatypes"
+	"gorm.io/gorm/clause"
+
+	"rsgit.ru/rsmon/rsmon/app/models/concerns"
+)
+
+// Task kinds stored in the tasks.kind column. The plan (docs/plans/worker-notifier-mvp.md
+// section 4.1) reserves the same enum for checks and notifications; this phase only
+// emits notification rows but the enum is shared so the selector can stay a single
+// function.
+const (
+	TaskKindNotification = "notification"
+	TaskKindCheck        = "check"
+	TaskKindServerMetric = "server_metric"
+)
+
+// Task states for the durable task envelope.
+const (
+	TaskStateQueued      = "queued"
+	TaskStateLeased      = "leased"
+	TaskStateSucceeded   = "succeeded"
+	TaskStateFailedRetry = "failed_retry"
+	TaskStateFailedPerm  = "failed_perm"
+	TaskStateDead        = "dead"
+)
+
+// Notification result statuses reported by the worker (mirrors the wire enum so the
+// result handler can decode without re-typing the constants).
+const (
+	NotificationResultDelivered = "delivered"
+	NotificationResultRetryable = "retryable"
+	NotificationResultPermanent = "permanent"
+	NotificationResultPartial   = "partial"
+)
+
+// SkipLockedClause is the SELECT ... FOR UPDATE SKIP LOCKED clause used by
+// every worker-pool selector (checks in check_jobs.ChecksForWorker and
+// tasks in task_selector.TasksForWorker / TasksForWorkerNotification).
+// Sharing the value keeps the SQL identical across selectors so goconst
+// does not flag the literal, and a future change (e.g. NOWAIT) only has
+// to touch one place.
+var SkipLockedClause = clause.Locking{Strength: "UPDATE", Options: "SKIP LOCKED"}
+
+// Task is the durable envelope for both check and notification work executed by the
+// distributed worker pool. Selection uses FOR UPDATE SKIP LOCKED per worker poll so
+// a single primary key or sequence never becomes the bottleneck.
+//
+// Phase 1 (this commit) only emits notification tasks. The `kind` discriminator and
+// capability filters are designed to accept checks in phase 2 without a schema change.
+type Task struct {
+	concerns.Model
+
+	JobID     string `gorm:"uniqueIndex;size:64" json:"job_id"`
+	Kind      string `gorm:"size:32;index" json:"kind"`
+	State     string `gorm:"size:32;index" json:"state"`
+	LastError string `gorm:"type:text" json:"last_error"`
+
+	// Tenancy + audit anchor. AccountID is required for the capability match in
+	// TasksForWorker; monitor_id / message_id / contact_id are denormalized for
+	// fast admin queries.
+	AccountID int64  `gorm:"index" json:"account_id"`
+	MonitorID *int64 `gorm:"index" json:"monitor_id,omitempty"`
+	CheckID   *int64 `json:"check_id,omitempty"`
+	MessageID *int64 `json:"message_id,omitempty"`
+	ContactID *int64 `json:"contact_id,omitempty"`
+
+	// Payload is the kind-specific blob the worker needs to execute. For
+	// notifications the producer pre-renders subject/body so the worker does not
+	// need templating context (see RenderNotificationContent in internal/notifier).
+	Payload datatypes.JSON `gorm:"type:jsonb" json:"payload"`
+
+	// Scheduling + retry envelope. NotBefore is set to NOW() by the producer and
+	// bumped by the result handler on retryable failures. Deadline is a soft cap
+	// the selector can use to skip stale tasks.
+	NotBefore time.Time  `json:"not_before"`
+	Deadline  *time.Time `json:"deadline,omitempty"`
+
+	// LeaseOwner + LeaseExpiresAt are owned by the selector while the task is
+	// in state=leased. The reaper clears them when the lease expires.
+	LeaseOwner     string     `gorm:"size:128" json:"lease_owner"`
+	LeaseToken     string     `gorm:"size:64" json:"-"`
+	LeaseExpiresAt *time.Time `json:"lease_expires_at,omitempty"`
+
+	Attempts    int `json:"attempts"`
+	MaxAttempts int `json:"max_attempts"`
+
+	// IdempotencyKey is unique per logical event so a retry of the producer's
+	// enqueue never produces a second Task row. See EnqueueNotificationTask.
+	IdempotencyKey string `gorm:"uniqueIndex;size:255" json:"idempotency_key"`
+
+	// Result holds the most recent worker result body (NotificationResultReport or
+	// CheckResultReport shape, depending on Kind). It is JSONB so the admin UI can
+	// pretty-print without a separate result table for transient lookups.
+	Result      datatypes.JSON `gorm:"type:jsonb" json:"result"`
+	SucceededAt *time.Time     `json:"succeeded_at,omitempty"`
+
+	concerns.Timestamped
+}
+
+// TaskReplay records the single operator-initiated replay of a dead task.
+// OriginalTaskID is unique, making repeated clicks/API retries idempotent.
+type TaskReplay struct {
+	concerns.Model
+	OriginalTaskID int64 `gorm:"uniqueIndex" json:"original_task_id"`
+	RequeuedTaskID int64 `gorm:"uniqueIndex" json:"requeued_task_id"`
+	OperatorUserID int64 `gorm:"index" json:"operator_user_id"`
+	concerns.Timestamped
+}
+
+// TableName overrides the default table name so pluralization stays consistent
+// with the rest of the schema (tasks, not "task" or "taskses").
+func (Task) TableName() string {
+	return "tasks"
+}
+
+// NotificationDelivery is the per-attempt audit row required by section 7.5 of the
+// plan ("Audit rows: each successful or failed delivery writes a row in a new
+// notification_deliveries table"). The result handler appends one row per result
+// frame, which lets support answer "did the customer ever get this alert" without
+// scanning application logs.
+type NotificationDelivery struct {
+	concerns.Model
+
+	MessageID int64  `gorm:"index" json:"message_id"`
+	WorkerID  string `gorm:"size:128;index" json:"worker_id"`
+	TaskID    int64  `gorm:"index" json:"task_id"`
+
+	Status string `gorm:"size:32" json:"status"`
+	Error  string `gorm:"type:text" json:"error"`
+
+	DurationMs       int    `json:"duration_ms"`
+	ProviderResponse string `gorm:"type:text" json:"provider_response"`
+
+	concerns.Timestamped
+}
+
+// TableName mirrors the plan's preferred lowercase plural.
+func (NotificationDelivery) TableName() string {
+	return "notification_deliveries"
+}