docs: Remove section about use of objects

- Revised cmdeploy documentation in doc/source/overview.rst to reflect
  the recent revisions to the Deployer interface.

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## untagged
 
+- Organized cmdeploy into install, configure, and activate stages
+  ([#695](https://github.com/chatmail/relay/pull/695))
+
 - docs: move readme.md docs to sphinx documentation rendered at https://chatmail.at/doc/relay 
   ([#711](https://github.com/chatmail/relay/pull/711))
 

cmdeploy/src/cmdeploy/acmetool/__init__.py

@@ -2,104 +2,121 @@ import importlib.resources
 
 from pyinfra.operations import apt, files, server, systemd
 
+from ..deployer import Deployer
 
-def deploy_acmetool(email="", domains=[]):
-    """Deploy acmetool."""
-    apt.packages(
-        name="Install acmetool",
-        packages=["acmetool"],
-    )
 
-    files.file(
-        name="Remove old acmetool cronjob, it is replaced with systemd timer.",
-        path="/etc/cron.d/acmetool",
-        present=False,
-    )
+class AcmetoolDeployer(Deployer):
+    def __init__(self, email, domains):
+        self.domains = domains
+        self.email = email
+        self.need_restart_redirector = False
+        self.need_restart_reconcile_service = False
+        self.need_restart_reconcile_timer = False
 
-    files.put(
-        name="Install acmetool hook.",
-        src=importlib.resources.files(__package__).joinpath("acmetool.hook").open("rb"),
-        dest="/etc/acme/hooks/nginx",
-        user="root",
-        group="root",
-        mode="755",
-    )
-    files.file(
-        name="Remove acmetool hook from the wrong location where it was previously installed.",
-        path="/usr/lib/acme/hooks/nginx",
-        present=False,
-    )
+    def install(self):
+        apt.packages(
+            name="Install acmetool",
+            packages=["acmetool"],
+        )
 
-    files.template(
-        src=importlib.resources.files(__package__).joinpath("response-file.yaml.j2"),
-        dest="/var/lib/acme/conf/responses",
-        user="root",
-        group="root",
-        mode="644",
-        email=email,
-    )
+        files.file(
+            name="Remove old acmetool cronjob, it is replaced with systemd timer.",
+            path="/etc/cron.d/acmetool",
+            present=False,
+        )
 
-    files.template(
-        src=importlib.resources.files(__package__).joinpath("target.yaml.j2"),
-        dest="/var/lib/acme/conf/target",
-        user="root",
-        group="root",
-        mode="644",
-    )
+        files.put(
+            name="Install acmetool hook.",
+            src=importlib.resources.files(__package__).joinpath("acmetool.hook").open("rb"),
+            dest="/etc/acme/hooks/nginx",
+            user="root",
+            group="root",
+            mode="755",
+        )
+        files.file(
+            name="Remove acmetool hook from the wrong location where it was previously installed.",
+            path="/usr/lib/acme/hooks/nginx",
+            present=False,
+        )
 
-    service_file = files.put(
-        src=importlib.resources.files(__package__).joinpath(
-            "acmetool-redirector.service"
-        ),
-        dest="/etc/systemd/system/acmetool-redirector.service",
-        user="root",
-        group="root",
-        mode="644",
-    )
+    def configure(self):
+        files.template(
+            src=importlib.resources.files(__package__).joinpath("response-file.yaml.j2"),
+            dest="/var/lib/acme/conf/responses",
+            user="root",
+            group="root",
+            mode="644",
+            email=self.email,
+        )
 
-    systemd.service(
-        name="Setup acmetool-redirector service",
-        service="acmetool-redirector.service",
-        running=True,
-        enabled=True,
-        restarted=service_file.changed,
-    )
+        files.template(
+            src=importlib.resources.files(__package__).joinpath("target.yaml.j2"),
+            dest="/var/lib/acme/conf/target",
+            user="root",
+            group="root",
+            mode="644",
+        )
 
-    reconcile_service_file = files.put(
-        src=importlib.resources.files(__package__).joinpath(
-            "acmetool-reconcile.service"
-        ),
-        dest="/etc/systemd/system/acmetool-reconcile.service",
-        user="root",
-        group="root",
-        mode="644",
-    )
+        service_file = files.put(
+            src=importlib.resources.files(__package__).joinpath(
+                "acmetool-redirector.service"
+            ),
+            dest="/etc/systemd/system/acmetool-redirector.service",
+            user="root",
+            group="root",
+            mode="644",
+        )
+        self.need_restart_redirector = service_file.changed
 
-    systemd.service(
-        name="Setup acmetool-reconcile service",
-        service="acmetool-reconcile.service",
-        running=False,
-        enabled=False,
-        daemon_reload=reconcile_service_file.changed,
-    )
+        reconcile_service_file = files.put(
+            src=importlib.resources.files(__package__).joinpath(
+                "acmetool-reconcile.service"
+            ),
+            dest="/etc/systemd/system/acmetool-reconcile.service",
+            user="root",
+            group="root",
+            mode="644",
+        )
+        self.need_restart_reconcile_service = reconcile_service_file.changed
 
-    reconcile_timer_file = files.put(
-        src=importlib.resources.files(__package__).joinpath("acmetool-reconcile.timer"),
-        dest="/etc/systemd/system/acmetool-reconcile.timer",
-        user="root",
-        group="root",
-        mode="644",
-    )
+        reconcile_timer_file = files.put(
+            src=importlib.resources.files(__package__).joinpath("acmetool-reconcile.timer"),
+            dest="/etc/systemd/system/acmetool-reconcile.timer",
+            user="root",
+            group="root",
+            mode="644",
+        )
+        self.need_restart_reconcile_timer = reconcile_timer_file.changed
 
-    systemd.service(
-        name="Setup acmetool-reconcile timer",
-        service="acmetool-reconcile.timer",
-        running=True,
-        enabled=True,
-        daemon_reload=reconcile_timer_file.changed,
-    )
+    def activate(self):
+        systemd.service(
+            name="Setup acmetool-redirector service",
+            service="acmetool-redirector.service",
+            running=True,
+            enabled=True,
+            restarted=self.need_restart_redirector,
+        )
+        self.need_restart_redirector = False
 
-    server.shell(
-        name=f"Request certificate for: {', '.join(domains)}",
-        commands=[f"acmetool want --xlog.severity=debug {' '.join(domains)}"],
-    )
+        systemd.service(
+            name="Setup acmetool-reconcile service",
+            service="acmetool-reconcile.service",
+            running=False,
+            enabled=False,
+            daemon_reload=self.need_restart_reconcile_service,
+        )
+        self.need_restart_reconcile_service = False
+
+        systemd.service(
+            name="Setup acmetool-reconcile timer",
+            service="acmetool-reconcile.timer",
+            running=True,
+            enabled=True,
+            daemon_reload=self.need_restart_reconcile_timer,
+        )
+        self.need_restart_reconcile_timer = False
+
+        server.shell(
+            name=f"Request certificate for: {', '.join(self.domains)}",
+            commands=[f"acmetool want --xlog.severity=debug {' '.join(self.domains)}"],
+        )

cmdeploy/src/cmdeploy/deployer.py

@@ -0,0 +1,57 @@
+import os
+
+from pyinfra.operations import server
+
+
+class Deployment:
+    def install(self, deployer):
+        # optional 'required_users' contains a list of (user, group, secondary-group-list) tuples.
+        # If the group is None, no group is created corresponding to that user.
+        # If the secondary group list is not None, all listed groups are created as well.
+        required_users = getattr(deployer, "required_users", [])
+        for user, group, groups in required_users:
+            if group is not None:
+                server.group(
+                    name="Create {} group".format(group), group=group, system=True
+                )
+            if groups is not None:
+                for group2 in groups:
+                    server.group(
+                        name="Create {} group".format(group2), group=group2, system=True
+                    )
+            server.user(
+                name="Create {} user".format(user),
+                user=user,
+                group=group,
+                groups=groups,
+                system=True,
+            )
+
+        deployer.install()
+
+    def configure(self, deployer):
+        deployer.configure()
+
+    def activate(self, deployer):
+        deployer.activate()
+
+    def perform_stages(self, deployers):
+        default_stages = "install,configure,activate"
+        stages = os.getenv("CMDEPLOY_STAGES", default_stages).split(",")
+
+        for stage in stages:
+            for deployer in deployers:
+                getattr(self, stage)(deployer)
+
+
+class Deployer:
+    need_restart = False
+
+    def install(self):
+        pass
+
+    def configure(self):
+        pass
+
+    def activate(self):
+        pass

cmdeploy/src/cmdeploy/policy-rc.d

@@ -0,0 +1,3 @@
+#!/bin/sh
+echo "All runlevel operations denied by policy" >&2
+exit 101

doc/source/overview.rst

@@ -297,3 +297,48 @@ actually it is a problem with your TLS certificate.
 .. _nginx: https://nginx.org
 .. _pyinfra: https://pyinfra.com
 
+
+Architecture of cmdeploy
+------------------------
+
+cmdeploy is a Python program that uses the pyinfra library to deploy
+chatmail relays, with all the necessary software, configuration, and
+services.  The deployment process performs three primary types of
+operation:
+
+1. Installation of software, universal across all deployments.
+2. Configuration of software, with deploy-specific variations.
+3. Activation of services.
+
+The process is implemented through a family of "deployer" objects
+which all derive from a common ``Deployer`` base class, defined in
+cmdeploy/src/cmdeploy/deployer.py.  Each object provides
+implementation methods for the three stages -- install, configure, and
+activate.  The top-level procedure in ``deploy_chatmail()`` calls
+these methods for all the deployer objects, via the
+``Deployment.perform_stages()`` method, also defined in deployer.py.
+This first calls all the install methods, then the configure methods,
+then the activate methods.
+
+The ``Deployment`` class also implements support for a CMDEPLOY_STAGES
+environment variable, which allows limiting the process to specific
+stages.  Note that some deployers are stateful between the stages
+(this is one reason why they are implemented as objects), and that
+state will not get propagated between stages when run in separate
+invocations of cmdeploy.  This environment variable is intended for
+use in future revisions to support building Docker images with
+software pre-installed, and configuration of containers at run time
+from environment variables.
+
+The, ``install()`` methods for the deployer classes should use 'self'
+as little as possible, preferably not at all.  In particular,
+``install()`` methods should never depend on "config" data, such as
+the config dictionary in ``self.config`` or specific values like
+``self.mail_domain``.  This ensures that these methods can be used to
+perform generic installation operations that are applicable across
+multiple relay deployments, and therefore can be called in the process
+of building a general-purpose container image.
+
+Operations that start services for systemd-based deployments should
+only be called from the ``activate_impl()`` methods.  These methods
+will not be called in non-systemd container environments.