core -> metropolis

Smalltown is now called Metropolis!

This is the first commit in a series of cleanup commits that prepare us
for an open source release. This one just some Bazel packages around to
follow a stricter directory layout.

All of Metropolis now lives in `//metropolis`.

All of Metropolis Node code now lives in `//metropolis/node`.

All of the main /init now lives in `//m/n/core`.

All of the Kubernetes functionality/glue now lives in `//m/n/kubernetes`.

Next steps:
     - hunt down all references to Smalltown and replace them appropriately
     - narrow down visibility rules
     - document new code organization
     - move `//build/toolchain` to `//monogon/build/toolchain`
     - do another cleanup pass between `//golibs` and
       `//monogon/node/{core,common}`.
     - remove `//delta` and `//anubis`

Fixes T799.

Test Plan: Just a very large refactor. CI should help us out here.

Bug: T799

X-Origin-Diff: phab/D667
GitOrigin-RevId: 6029b8d4edc42325d50042596b639e8b122d0ded
diff --git a/metropolis/node/core/delve_enabled.go b/metropolis/node/core/delve_enabled.go
new file mode 100644
index 0000000..b3b859c
--- /dev/null
+++ b/metropolis/node/core/delve_enabled.go
@@ -0,0 +1,41 @@
+// Copyright 2020 The Monogon Project Authors.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"os/exec"
+
+	"git.monogon.dev/source/nexantic.git/metropolis/node/core/network"
+)
+
+// initializeDebugger attaches Delve to ourselves and exposes it on common.DebuggerPort
+// This is coupled to compilation_mode=dbg because otherwise Delve doesn't have the necessary DWARF debug info
+func initializeDebugger(networkSvc *network.Service) {
+	go func() {
+		// This is intentionally delayed until network becomes available since Delve for some reason connects to itself
+		// and in early-boot no network interface is available to do that through. Also external access isn't possible
+		// early on anyways.
+		networkSvc.GetIP(context.Background(), true)
+		dlvCmd := exec.Command("/dlv", "--headless=true", fmt.Sprintf("--listen=:%v", common.DebuggerPort),
+			"--accept-multiclient", "--only-same-user=false", "attach", "--continue", "1", "/init")
+		if err := dlvCmd.Start(); err != nil {
+			panic(err)
+		}
+	}()
+}