dev-docs: Go package docs (#958)

* Remove unused package

* Add Go package docs to most packages

Signed-off-by: Daniel Weiße <dw@edgeless.systems>
Signed-off-by: Fabian Kammel <fk@edgeless.systems>
Signed-off-by: Paul Meyer <49727155+katexochen@users.noreply.github.com>
Co-authored-by: Paul Meyer <49727155+katexochen@users.noreply.github.com>
Co-authored-by: Fabian Kammel <fk@edgeless.systems>

disk-mapper/internal/mapper/mapper.go

@@ -4,6 +4,15 @@ Copyright (c) Edgeless Systems GmbH
 SPDX-License-Identifier: AGPL-3.0-only
 */
 
+/*
+Package mapper uses libcryptsetup to format and map crypt devices.
+
+This is used by the disk-mapper to set up a node's state disk.
+
+All interaction with libcryptsetup should be done here.
+
+Warning: This package is not thread safe, since libcryptsetup is not thread safe.
+*/
 package mapper
 
 import (
@@ -24,7 +33,7 @@ import (
 //	https://stackoverflow.com/questions/30553386/cryptsetup-backend-safe-with-multithreading
 var packageLock = sync.Mutex{}
 
-// Mapper handles actions for formating and mapping crypt devices.
+// Mapper handles actions for formatting and mapping crypt devices.
 type Mapper struct {
 	device cryptDevice
 	log    *logger.Logger

disk-mapper/internal/recoveryserver/recoveryserver.go

@@ -4,6 +4,15 @@ Copyright (c) Edgeless Systems GmbH
 SPDX-License-Identifier: AGPL-3.0-only
 */
 
+/*
+Package recoveryserver implements the gRPC endpoints for recovering a restarting node.
+
+The endpoint is only available for control-plane nodes,
+worker nodes should only rejoin the cluster using Constellation's JoinService.
+
+This endpoint can be used by an admin in case of a complete cluster shutdown,
+in which case a node is unable to rejoin the cluster automatically.
+*/
 package recoveryserver
 
 import (

disk-mapper/internal/rejoinclient/rejoinclient.go

@@ -4,6 +4,11 @@ Copyright (c) Edgeless Systems GmbH
 SPDX-License-Identifier: AGPL-3.0-only
 */
 
+/*
+Package rejoinclient handles the automatic rejoining of a restarting node.
+
+It does so by continuously sending rejoin requests to the JoinService of available control-plane endpoints.
+*/
 package rejoinclient
 
 import (

disk-mapper/internal/setup/setup.go

@@ -4,6 +4,11 @@ Copyright (c) Edgeless Systems GmbH
 SPDX-License-Identifier: AGPL-3.0-only
 */
 
+/*
+Package setup handles setting up rejoinclient and recoveryserver for the disk-mapper.
+
+On success of either of these services, the state disk is decrypted and the node is tainted as initialized by updating it's PCRs.
+*/
 package setup
 
 import (

disk-mapper/internal/systemd/systemd.go

@@ -4,6 +4,7 @@ Copyright (c) Edgeless Systems GmbH
 SPDX-License-Identifier: AGPL-3.0-only
 */
 
+// Package systemd configures systemd units for encrypted volumes.
 package systemd
 
 import (