treewide: add license header and enable haslicense linter
Change-Id: I873a8d4082d75e8f813d8a726a41187eea7a065e
Reviewed-on: https://review.monogon.dev/c/monogon/+/3825
Tested-by: Jenkins CI
Reviewed-by: Leopold Schabel <leo@monogon.tech>
diff --git a/metropolis/node/core/metrics/discovery.go b/metropolis/node/core/metrics/discovery.go
index 116291e..fea4582 100644
--- a/metropolis/node/core/metrics/discovery.go
+++ b/metropolis/node/core/metrics/discovery.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
package metrics
import (
diff --git a/metropolis/node/core/metrics/exporters.go b/metropolis/node/core/metrics/exporters.go
index 2e8c1df..003a690 100644
--- a/metropolis/node/core/metrics/exporters.go
+++ b/metropolis/node/core/metrics/exporters.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
package metrics
import (
diff --git a/metropolis/node/core/metrics/fake_exporter/fake_exporter.go b/metropolis/node/core/metrics/fake_exporter/fake_exporter.go
index 919851e..c289c60 100644
--- a/metropolis/node/core/metrics/fake_exporter/fake_exporter.go
+++ b/metropolis/node/core/metrics/fake_exporter/fake_exporter.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
// fake_exporter is a tiny Prometheus-compatible metrics exporter which exports a
// single metric with a value configured at startup. It is used to test the
// metrics service.
diff --git a/metropolis/node/core/metrics/metrics.go b/metropolis/node/core/metrics/metrics.go
index b07a980..9abed54 100644
--- a/metropolis/node/core/metrics/metrics.go
+++ b/metropolis/node/core/metrics/metrics.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
package metrics
import (
diff --git a/metropolis/node/core/metrics/metrics_test.go b/metropolis/node/core/metrics/metrics_test.go
index fb5e3dc..b7c3eab 100644
--- a/metropolis/node/core/metrics/metrics_test.go
+++ b/metropolis/node/core/metrics/metrics_test.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
package metrics
import (