A report the store cannot take yet is handed back to the broker, not acknowledged and lost (novox/hq issue 082)

internal/inventory/reachable.go

@@ -0,0 +1,35 @@
+package inventory
+
+import (
+	"errors"
+	"strings"
+
+	"github.com/jackc/pgx/v5/pgconn"
+)
+
+// Unreachable says whether an error means the store could not be asked right now, rather than
+// that it answered no.
+//
+// The difference decides whether something worth keeping is kept or lost. The store is recreated
+// when the foundation is adopted (ADR 0078), and for those seconds every write fails with "the
+// database system is starting up" or a refused connection; a caller that treats that like a
+// refusal throws away what it was writing — a node's report of the apply that caused the restart
+// was lost exactly so, and the mesh never heard from the node again (novox/hq issue 082).
+//
+// Unreachable is a connection that failed, and the server classes that mean "not now": 08
+// (connection exception) and 57 (operator intervention — starting up, shutting down, admin
+// shutdown, cannot connect now). Everything else is an answer, and asking again gets the same one.
+func Unreachable(err error) bool {
+	if err == nil {
+		return false
+	}
+	var connect *pgconn.ConnectError
+	if errors.As(err, &connect) {
+		return true
+	}
+	var pg *pgconn.PgError
+	if errors.As(err, &pg) {
+		return strings.HasPrefix(pg.Code, "08") || strings.HasPrefix(pg.Code, "57")
+	}
+	return false
+}