hooks: execute hook scripts as builtin late commands

When executing late commands, we now start by executing run-parts over
the /etc/subiquity/postinst.d directory (by default) if it exists.

A failure in run-parts is not considered critical so any other
late_commands will run no matter what.

Signed-off-by: Olivier Gayot <olivier.gayot@canonical.com>

Makefile

@@ -7,7 +7,8 @@ PYTHONPATH=$(shell pwd):$(shell pwd)/probert:$(shell pwd)/curtin
 PROBERTDIR=./probert
 PROBERT_REPO=https://github.com/canonical/probert
 DRYRUN?=--dry-run --bootloader uefi --machine-config examples/simple.json \
-	--source-catalog examples/install-sources.yaml
+	--source-catalog examples/install-sources.yaml \
+	--postinst-hooks-dir examples/postinst.d/
 SYSTEM_SETUP_DRYRUN?=--dry-run
 export PYTHONPATH
 CWD := $(shell pwd)

examples/postinst.d/copy_nm_connections

@@ -0,0 +1,35 @@
+#!/bin/bash
+
+prefix="$TARGET_MOUNT_POINT"/etc/NetworkManager/system-connections
+
+echo "Copying NM connections to target"
+
+mkdir --parents -- "$prefix"
+cat > "$prefix"/subiquity-test.nmconnection << EOF
+[connection]
+id=Subiquity Test
+uuid=5bbf9dda-f3a9-4967-970e-aba55c8b18f0
+type=wifi
+interface-name=wlp0s20f3
+permissions=
+
+[wifi]
+mode=infrastructure
+ssid=TestConnection-5G
+
+[wifi-security]
+auth-alg=open
+key-mgmt=wpa-psk
+psk=nCjIqJ4G
+
+[ipv4]
+dns-search=
+method=auto
+
+[ipv6]
+addr-gen-mode=stable-privacy
+dns-search=
+method=auto
+
+[proxy]
+EOF

subiquity/cmd/server.py

@@ -16,6 +16,7 @@
 import argparse
 import logging
 import os
+import pathlib
 import shlex
 import sys
 
@@ -104,6 +105,9 @@ def make_server_args_parser():
         '--storage-version', action='store', type=int)
     parser.add_argument(
         '--use-os-prober', action='store_true', default=False)
+    parser.add_argument(
+        '--postinst-hooks-dir', default='/etc/subiquity/postinst.d',
+        type=pathlib.Path)
     return parser
 
 

subiquity/server/controllers/cmdlist.py

@@ -57,6 +57,7 @@ class CmdListController(NonInteractiveController):
             'items': {'type': 'string'},
             },
         }
+    builtin_cmds: Sequence[Command] = ()
     cmds: Sequence[Command] = ()
     cmd_check = True
     syslog_id = None
@@ -74,7 +75,7 @@ class CmdListController(NonInteractiveController):
     @with_context()
     async def run(self, context):
         env = self.env()
-        for i, cmd in enumerate(self.cmds):
+        for i, cmd in enumerate(tuple(self.builtin_cmds) + tuple(self.cmds)):
             desc = cmd.desc()
             with context.child("command_{}".format(i), desc):
                 args = cmd.as_args_list()
@@ -109,6 +110,21 @@ class LateController(CmdListController):
         super().__init__(app)
         self.syslog_id = app.log_syslog_id
 
+        try:
+            hooks_dir = self.app.opts.postinst_hooks_dir
+        except AttributeError:
+            # NOTE: system_setup imports this controller ; but does not use the
+            # postinst hooks mechanism.
+            pass
+        else:
+            if hooks_dir.is_dir():
+                self.builtin_cmds = [
+                    Command(
+                        args=["run-parts", "--debug", "--", str(hooks_dir)],
+                        check=False,
+                    ),
+                ]
+
     def env(self):
         env = super().env()
         env['TARGET_MOUNT_POINT'] = self.app.base_model.target