feat(tasks): implement atomic claims and leases

backend-api/internal/config/config_test.go

@@ -29,6 +29,16 @@ func TestLoadUsesSafeDefaults(t *testing.T) {
 		cfg.MaxHeaderBytes <= 0 {
 		t.Fatal("server safety limits must all be positive")
 	}
+	if cfg.ClaimLease != 10*time.Minute ||
+		cfg.RunningLease != 90*time.Second ||
+		cfg.ReadinessTTL != 2*time.Minute {
+		t.Fatalf(
+			"lifecycle durations = %s / %s / %s",
+			cfg.ClaimLease,
+			cfg.RunningLease,
+			cfg.ReadinessTTL,
+		)
+	}
 	if cfg.ShutdownTimeout > 30*time.Second {
 		t.Fatalf("ShutdownTimeout = %s", cfg.ShutdownTimeout)
 	}
@@ -41,6 +51,9 @@ func TestLoadAcceptsExplicitConfiguration(t *testing.T) {
 		AssetDirectoryEnvironment: "tmp/assets",
 		TLSCertificateEnvironment: "tmp/server.crt",
 		TLSPrivateKeyEnvironment:  "tmp/server.key",
+		ClaimLeaseEnvironment:     "15m",
+		RunningLeaseEnvironment:   "2m",
+		ReadinessTTLEnvironment:   "3m",
 	}
 
 	cfg, err := Load(mapEnvironment(values))
@@ -65,6 +78,16 @@ func TestLoadAcceptsExplicitConfiguration(t *testing.T) {
 			cfg.TLSPrivateKey,
 		)
 	}
+	if cfg.ClaimLease != 15*time.Minute ||
+		cfg.RunningLease != 2*time.Minute ||
+		cfg.ReadinessTTL != 3*time.Minute {
+		t.Fatalf(
+			"lifecycle durations = %s / %s / %s",
+			cfg.ClaimLease,
+			cfg.RunningLease,
+			cfg.ReadinessTTL,
+		)
+	}
 }
 
 func TestLoadRejectsUnsafeOrInvalidValues(t *testing.T) {
@@ -145,6 +168,24 @@ func TestLoadRejectsUnsafeOrInvalidValues(t *testing.T) {
 				TLSPrivateKeyEnvironment:  " ",
 			},
 		},
+		{
+			name: "claim lease below minimum",
+			values: map[string]string{
+				ClaimLeaseEnvironment: "59s",
+			},
+		},
+		{
+			name: "running lease above maximum",
+			values: map[string]string{
+				RunningLeaseEnvironment: "11m",
+			},
+		},
+		{
+			name: "invalid readiness TTL",
+			values: map[string]string{
+				ReadinessTTLEnvironment: "soon",
+			},
+		},
 	}
 
 	for _, test := range tests {