[__letsencrypt_cert] Fix various issues with hooks.

Closes #853, see issue for full description / discussion.

Short summary:
- There was about 6.53% chances of `--renewal-hook` not being applied
- Using --automatic-renewal in one cert and not in another was an error.
- It was not possible to use different hooks for different certificates.
- FreeBSD support was utterly broken.

cdist/conf/type/__letsencrypt_cert/man.rst

@@ -1,16 +1,33 @@
 cdist-type__letsencrypt_cert(7)
 ===============================
 
+
 NAME
 ----
 
 cdist-type__letsencrypt_cert - Get an SSL certificate from Let's Encrypt
 
+
 DESCRIPTION
 -----------
 
 Automatically obtain a Let's Encrypt SSL certificate using Certbot.
 
+This type attempts to setup automatic renewals always. In many Linux
+distributions, that is the case out of the box, see:
+https://certbot.eff.org/docs/using.html#automated-renewals
+
+For Alpine Linux and Arch Linux, we setup a system-wide cronjob that
+attempts to renew certificates daily.
+
+If you are using FreeBSD, we configure periodic(8) as recommended by
+the port mantainer, so there will be a weekly attempt at renewal.
+
+If your OS is not mentioned here or on Certbot's docs as having
+support for automated renewals, please make sure you check your OS
+and possibly patch this type so the system-wide cronjob is installed.
+
+
 REQUIRED PARAMETERS
 -------------------
 
@@ -21,6 +38,7 @@ object id
 admin-email
     Where to send Let's Encrypt emails like "certificate needs renewal".
 
+
 OPTIONAL PARAMETERS
 -------------------
 
@@ -36,25 +54,68 @@ webroot
     The path to your webroot, as set up in your webserver config. If this
     parameter is not present, Certbot will be run in standalone mode.
 
+
 OPTIONAL MULTIPLE PARAMETERS
 ----------------------------
 
-renew-hook
-    Renew hook command directly passed to Certbot in cron job.
-
 domain
     Domains to be included in the certificate. When specified then object id
     is not used as a domain.
 
+deploy-hook
+    Command to be executed only when the certificate associated with this
+    ``$__object_id`` is issued or renewed.
+    You can specify it multiple times, but any failure will prevent further
+    commands from being executed.
+
+    For this command, the
+    shell variable ``$RENEWED_LINEAGE`` will point to the
+    config live subdirectory (for example,
+    ``/etc/letsencrypt/live/${__object_id}``) containing the
+    new certificates and keys; the shell variable
+    ``$RENEWED_DOMAINS`` will contain a space-delimited list
+    of renewed certificate domains (for example,
+    ``example.com www.example.com``)
+
+pre-hook
+    Command to be run in a shell before obtaining any
+    certificates.
+    You can specify it multiple times, but any failure will prevent further
+    commands from being executed.
+
+    Note these run regardless of which certificate is attempted, you may want to
+    manage these system-wide hooks with ``__file`` in
+    ``/etc/letsencrypt/renewal-hooks/pre/``.
+
+    Intended primarily for renewal, where it
+    can be used to temporarily shut down a webserver that
+    might conflict with the standalone plugin. This will
+    only be called if a certificate is actually to be
+    obtained/renewed.
+
+post-hook
+    Command to be run in a shell after attempting to
+    obtain/renew certificates.
+    You can specify it multiple times, but any failure will prevent further
+    commands from being executed.
+
+    Note these run regardless of which certificate was attempted, you may want to
+    manage these system-wide hooks with ``__file`` in
+    ``/etc/letsencrypt/renewal-hooks/post/``.
+
+    Can be used to deploy
+    renewed certificates, or to restart any servers that
+    were stopped by --pre-hook. This is only run if an
+    attempt was made to obtain/renew a certificate.
+
+
 BOOLEAN PARAMETERS
 ------------------
 
-automatic-renewal
-    Install a cron job, which attempts to renew certificates daily.
-
 staging
     Obtain a test certificate from a staging server.
 
+
 MESSAGES
 --------
 
@@ -67,6 +128,7 @@ create
 remove
     Certificate was removed.
 
+
 EXAMPLES
 --------
 
@@ -75,8 +137,7 @@ EXAMPLES
     # use object id as domain
     __letsencrypt_cert example.com \
         --admin-email root@example.com \
-        --automatic-renewal \
+        --deploy-hook "service nginx reload" \
-        --renew-hook "service nginx reload" \
         --webroot /data/letsencrypt/root
 
 .. code-block:: sh
@@ -85,11 +146,10 @@ EXAMPLES
     # and example.com needs to be included again with domain parameter
     __letsencrypt_cert example.com \
         --admin-email root@example.com \
-        --automatic-renewal \
         --domain example.com \
         --domain foo.example.com \
         --domain bar.example.com \
-        --renew-hook "service nginx reload" \
+        --deploy-hook "service nginx reload" \
         --webroot /data/letsencrypt/root
 
 AUTHORS
@@ -99,11 +159,13 @@ AUTHORS
 | Kamila Součková <kamila--@--ksp.sk>
 | Darko Poljak <darko.poljak--@--gmail.com>
 | Ľubomír Kučera <lubomir.kucera.jr at gmail.com>
+| Evilham <contact@evilham.com>
+
 
 COPYING
 -------
 
-Copyright \(C) 2017-2018 Nico Schottelius, Kamila Součková, Darko Poljak and
+Copyright \(C) 2017-2021 Nico Schottelius, Kamila Součková, Darko Poljak and
 Ľubomír Kučera. You can redistribute it and/or modify it under the terms of
 the GNU General Public License as published by the Free Software Foundation,
 either version 3 of the License, or (at your option) any later version.

cdist/conf/type/__letsencrypt_cert/manifest

@@ -1,11 +1,13 @@
 #!/bin/sh
 
 certbot_fullpath="$(cat "${__object:?}/explorer/certbot-path")"
+state=$(cat "${__object}/parameter/state")
+os="$(cat "${__global:?}/explorer/os")"
 
 if [ -z "${certbot_fullpath}" ]; then
-	os="$(cat "${__global:?}/explorer/os")"
 	os_version="$(cat "${__global}/explorer/os_version")"
-
+	# Use this, very common value, as a default. It is OS-dependent
+	certbot_fullpath="/usr/bin/certbot"
 	case "$os" in
 		archlinux)
 			__package certbot
@@ -48,8 +50,6 @@ if [ -z "${certbot_fullpath}" ]; then
 					exit 1
 				;;
 			esac
-
-			certbot_fullpath=/usr/bin/certbot
 		;;
 		devuan)
 			case "$os_version" in
@@ -83,13 +83,10 @@ if [ -z "${certbot_fullpath}" ]; then
 					exit 1
 				;;
 			esac
-
-			certbot_fullpath=/usr/bin/certbot
 		;;
 		freebsd)
-			__package py27-certbot
+			__package py37-certbot
-
+			certbot_fullpath="/usr/local/bin/certbot"
-			certbot_fullpath=/usr/local/bin/certbot
 		;;
 		ubuntu)
 			__package certbot
@@ -101,18 +98,130 @@ if [ -z "${certbot_fullpath}" ]; then
 	esac
 fi
 
-if [ -f "${__object}/parameter/automatic-renewal" ]; then
+# Other OS-dependent values that we want to set every time
-	renew_hook_param="${__object}/parameter/renew-hook"
+LE_DIR="/etc/letsencrypt"
-	renew_hook=""
+certbot_cronjob_state="absent"
-	if [ -f "${renew_hook_param}" ]; then
+case "$os" in
-		while read -r hook; do
+	archlinux|alpine)
-			renew_hook="${renew_hook} --renew-hook \"${hook}\""
+		certbot_cronjob_state="present"
-		done < "${renew_hook_param}"
+	;;
-	fi
+	freebsd)
+		LE_DIR="/usr/local/etc/letsencrypt"
+		# FreeBSD uses periodic(8) instead of crontabs for this
+		__line "periodic.conf_weekly_certbot" \
+			--file "/etc/periodic.conf" \
+			--regex "^(#[[:space:]]*)?weekly_certbot_enable=.*" \
+			--state "replace" \
+			--line 'weekly_certbot_enable="YES"'
+	;;
+	*)
+	;;
+esac
 
-	__cron letsencrypt-certbot  \
+# This is only necessary in certain OS
+__cron letsencrypt-certbot \
 	--user root \
-		--command "${certbot_fullpath} renew -q ${renew_hook}" \
+	--command "${certbot_fullpath} renew -q" \
 	--hour 0 \
-		--minute 47
+	--minute 47 \
+	--state "${certbot_cronjob_state}"
+
+# Ensure hook directories
+HOOKS_DIR="${LE_DIR}/renewal-hooks"
+__directory "${LE_DIR}" --mode 0755
+require="__directory/${LE_DIR}" __directory "${HOOKS_DIR}" --mode 0755
+
+if [ -f "${__object}/parameter/domain" ]; then
+	domains="$(sort "${__object}/parameter/domain")"
+else
+	domains="${__object_id}"
 fi
+
+# Install hooks as needed
+for hook in deploy pre post; do
+	# Using something unique and specific to this object
+	hook_file="${HOOKS_DIR}/${hook}/${__object_id}.cdist.sh"
+	# Reasonable defaults
+	hook_source="${__object}/parameter/${hook}-hook"
+	hook_state="absent"
+	hook_contents_head="#!/bin/sh -e"
+	hook_contents_logic=""
+	hook_contents_tail=""
+
+	# Backwards compatibility
+	# Remove this when renew-hook is removed
+	# Falling back to renew-hook if deploy-hook is not passed
+	if [ "${hook}" = "deploy" ] && [ ! -f "${hook_source}" ]; then
+		hook_source="${__object}/parameter/renew-hook"
+	fi
+	if [ "${state}" = "present" ] && \
+		[ -f "${hook_source}" ]; then
+		# This hook is to be installed, let's generate it with some
+		# safety boilerplate
+		# Since certbot runs all hooks for all renewal processes
+		# (at each state for deploy, pre, post), it is up to us to
+		# differentiate whether or not the hook must run
+		hook_state="present"
+		hook_contents_head="$(cat <<EOF
+#!/bin/sh -e
+#
+# Managed remotely with https://cdi.st
+#
+# Domains for which this hook is supposed to apply
+lineage="${LE_DIR}/live/${__object_id}"
+domains="\$(cat <<eof
+${domains}
+eof
+)"
+EOF
+)"
+		case "${hook}" in
+			pre|post)
+				# Certbot is kind of terrible, we have
+				# no way of knowing what domain/lineage the
+				# hook is running for
+				hook_contents_logic="$(cat <<EOF
+# pre/post-hooks apply always due to a certbot limitation
+APPLY_HOOK="YES"
+EOF
+)"
+			;;
+			deploy)
+				hook_contents_logic="$(cat <<EOF
+# certbot defines these:
+# RENEWED_DOMAINS: DOMAIN1,DOMAIN2
+# RENEWED_LINEAGE: /etc/letsencrypt/live/__object_id
+# It feels more stable to use RENEWED_LINEAGE
+if [ "\${lineage}" = "\${RENEWED_LINEAGE}" ]; then
+	APPLY_HOOK="YES"
+fi
+EOF
+)"
+			;;
+			*)
+				echo "Unknown hook '${hook}'" >> /dev/stderr
+				exit 1
+			;;
+		esac
+
+		hook_contents_tail="$(cat <<EOF
+if [ -n "\${APPLY_HOOK}" ]; then
+$(sed -e 's/^/	//' "${hook_source}")
+fi
+EOF
+)"
+	fi
+	# Ensure hook directory exists
+	require="__directory/${HOOKS_DIR}" __directory "${HOOKS_DIR}/${hook}" \
+		--mode 0755
+	require="__directory/${HOOKS_DIR}/${hook}" __file "${hook_file}" \
+		--mode 0555 \
+		--source '-' \
+		--state "${hook_state}" <<EOF
+${hook_contents_head}
+
+${hook_contents_logic}
+
+${hook_contents_tail}
+EOF
+done

cdist/conf/type/__letsencrypt_cert/parameter/deprecated/automatic-renewal

@@ -0,0 +1,2 @@
+Deprecated in favour of consistent behaviour. It has no effect, see:
+https://code.ungleich.ch/ungleich-public/cdist/-/issues/853

cdist/conf/type/__letsencrypt_cert/parameter/deprecated/renew-hook

@@ -0,0 +1,2 @@
+This parameter has been deprecated in favour of --deploy-hook.
+See: https://code.ungleich.ch/ungleich-public/cdist/-/issues/853

cdist/conf/type/__letsencrypt_cert/parameter/optional_multiple

@@ -1,2 +1,5 @@
+deploy-hook
 domain
+post-hook
+pre-hook
 renew-hook