Setup unbound DNS resolver

If you run it as scripts/initenv.sh,
activating venv is useless as bash will exit immediately afterwards.

If you `source` it as suggested by README.md,
`set -e` will set the flag for the current shell
and your shell will exit as soon as some command returns non-zero status,
e.g. cmdeploy fails or you simply do `ls /foo/bar/baz` and `ls`
complains that `/foo/bar/baz` does not exist.

README.md

@@ -25,10 +25,11 @@ DNS domain name (FQDN), for example `chat.example.org`.
         ssh root@CHATMAIL_DOMAIN 
    ```
 
-2. Install the `cmdeploy` command in a virtualenv 
+2. Install the `cmdeploy` command in a virtualenv and activate it
 
    ```
-    source scripts/initenv.sh
+    scripts/initenv.sh
+    . venv/bin/activate
    ```
   
 3. Create chatmail configuration file `chatmail.ini`:

cmdeploy/src/cmdeploy/__init__.py

@@ -378,6 +378,20 @@ def deploy_chatmail(mail_domain: str, mail_server: str, dkim_selector: str) -> N
         system=True,
     )
 
+    # Run local DNS resolver `unbound`.
+    # `resolvconf` takes care of setting up /etc/resolv.conf
+    # to use 127.0.0.1 as the resolver.
+    apt.packages(
+        name="Install unbound",
+        packages="unbound",
+    )
+    systemd.service(
+        name="Start and enable unbound",
+        service="unbound.service",
+        running=True,
+        enabled=True,
+    )
+
     # Deploy acmetool to have TLS certificates.
     deploy_acmetool(nginx_hook=True, domains=[mail_server, f"mta-sts.{mail_server}"])
 

cmdeploy/src/cmdeploy/cmdeploy.py

@@ -155,7 +155,7 @@ def fmt_cmd_options(parser):
 
 
 def fmt_cmd(args, out):
-    """Run formattting fixes (fuff and black) on all chatmail source code."""
+    """Run formattting fixes (ruff and black) on all chatmail source code."""
 
     sources = [str(importlib.resources.files(x)) for x in ("chatmaild", "cmdeploy")]
     black_args = [shutil.which("black")]

scripts/initenv.sh

@@ -4,6 +4,3 @@ python3 -m venv venv
 
 venv/bin/pip install -e chatmaild 
 venv/bin/pip install -e cmdeploy
-
-source venv/bin/activate
-echo activated 'venv' python virtualenv environment containing "cmdeploy" tool