Implement notifications service with shared messaging and email drivers (#36)

backend/notifications/model/model.go

@@ -0,0 +1,58 @@
+package model
+
+import (
+	"git.sendico.io/tech/sxchnge/shared/database/record"
+	"time"
+)
+
+type State string
+
+const (
+	Queued    State = "queued"
+	Sending   State = "sending"
+	RetryWait State = "retry_wait"
+	Accepted  State = "accepted"
+	Failed    State = "failed"
+	Expired   State = "expired"
+	Unknown   State = "unknown"
+)
+
+type Request struct {
+	Key             string
+	UserID          string
+	TemplateID      string
+	TemplateVersion string
+	Parameters      map[string]string
+	Locale          string
+	Address         string
+	ExpiresAt       time.Time
+}
+
+// Email is a rendered immutable snapshot, independent of provider wire formats.
+type Email struct {
+	Address string
+	Subject string
+	HTML    string
+	Text    string
+}
+
+type Notification struct {
+	storable.Base   `bson:",inline"`
+	Caller          string    `bson:"caller"`
+	Key             string    `bson:"key"`
+	Fingerprint     string    `bson:"fingerprint"`
+	UserID          string    `bson:"user_id"`
+	TemplateID      string    `bson:"template_id"`
+	TemplateVersion string    `bson:"template_version"`
+	Email           Email     `bson:"email"`
+	Driver          string    `bson:"driver"`
+	State           State     `bson:"state"`
+	Attempts        uint32    `bson:"attempts"`
+	FailureCode     string    `bson:"failure_code"`
+	ExpiresAt       time.Time `bson:"expires_at"`
+	NextAttemptAt   time.Time `bson:"next_attempt_at"`
+	LeaseUntil      time.Time `bson:"lease_until"`
+	PurgeAt         time.Time `bson:"purge_at"`
+}
+
+func (*Notification) Collection() string { return "notifications" }