Try out this conditional restart stuff.

handlers/restart_services.yml

@@ -6,7 +6,7 @@
   action: service name=auditd state=restarted
 
 - name: restart apache
-  action: service name=httpd state=restarted
+  command: /usr/local/bin/conditional-restart.sh httpd httpd
 
 - name: reload apache
   action: service name=httpd state=reloaded
@@ -17,8 +17,20 @@
 - name: restart crond
   action: service name=crond state=restarted
 
+- name: restart fedmsg-gateway
+  command: /usr/local/bin/conditional-restart.sh fedmsg-gateway fedmsg-gateway
+
+- name: restart fedmsg-hub
+  command: /usr/local/bin/conditional-restart.sh fedmsg-hub fedmsg-hub
+
+- name: restart fedmsg-irc
+  command: /usr/local/bin/conditional-restart.sh fedmsg-irc fedmsg-irc
+
+- name: restart fedmsg-relay
+  command: /usr/local/bin/conditional-restart.sh fedmsg-relay fedmsg-relay
+
 - name: restart httpd
-  action: service name=httpd state=restarted
+  command: /usr/local/bin/conditional-restart.sh httpd httpd
 
 - name: reload httpd
   action: service name=httpd state=reloaded

roles/base/files/common-scripts/conditional-restart.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+# Restart SERVICE only if PACKAGE is installed.
+# We use this throughout handlers/restart_services.yml
+
+SERVICE=$1
+PACKAGE=$2
+
+/usr/bin/rpm -q $PACKAGE
+
+INSTALLED=$?
+
+if [ $INSTALLED -eq 0 ]; then
+    echo "Package $PACKAGE installed.  Attempting restart of $SERVICE."
+    /sbin/service $SERVICE restart
+    exit $?  # Exit with the /sbin/service status code
+fi
+
+# If the package wasn't installed, then pretend everything is fine.
+echo "Package $PACKAGE not installed.  Skipping restart of $SERVICE."
+exit 0

roles/fedmsg-hub/handlers/main.yml

@@ -1,2 +0,0 @@
-- name: restart fedmsg-hub
-  action: service name=fedmsg-hub state=restarted

roles/fedmsg_base/tasks/main.yml

@@ -16,8 +16,19 @@
   tags:
   - config
 
+# Any files that change need to restart any services that depend on them.  A
+# trick here is that some hosts have an httpd that uses fedmsg, while others do
+# not.  Some hosts have a fedmsg-hub that uses this config, while others do not.
+# Our handlers in handlers/restart_services.yml are smart enough to
+# *conditionally* restart these services, only if they are installed on the
+# system.
 - name: setup basic /etc/fedmsg.d/ contents
-  template: src="{{ item }}.j2" dest="/etc/fedmsg.d/{{ item }}" owner=root group=root mode=644
+  template: >
+    src="{{ item }}.j2"
+    dest="/etc/fedmsg.d/{{ item }}"
+    owner=root
+    group=root
+    mode=644
   with_items:
   - ssl.py
   - endpoints.py
@@ -32,6 +43,12 @@
   - base.py
   tags:
   - config
+  notify:
+  - restart httpd
+  - restart fedmsg-gateway
+  - restart fedmsg-hub
+  - restart fedmsg-irc
+  - restart fedmsg-relay
 
 - name: setup /etc/pki/fedmsg directory
   file: path=/etc/pki/fedmsg owner=root group=root mode=0755 state=directory