Add debugging info to certcheck list building

We've seen the certcheck list building loop fail because some host
doesn't ahve the appropriate var in its hostvars. Unfortunately ansible
logging doesn't record the value of the list iteration item when an
iteration fails. It only records this value when it succeeds....
Work around this with our own debugging output.

Additionally use a unique loop_var value in case we're hitting some sort
of 'item' name collision problem. It is just good practice to avoid
'item' anyway.

Change-Id: Ia3ed089187e0b8397413fbb989c44906d56811ae

playbooks/roles/letsencrypt-config-certcheck/tasks/build_le_domain_list.yaml

@@ -0,0 +1,12 @@
+# We've seen the lookups of hosts in hostvars below fail to find the
+# letsencrypt_certcheck_domains value. For some reason ansible doesn't
+# record the value of our loopvar when failing an iteration (it does when
+# the loop iteration succeeds) so we don't know where it is breaking. Add
+# our own debugging here to work around this problem.
+- name: Record host being looked up for le certcheck domains
+  debug:
+    msg: "Checking domains for {{ inv_hostname }}"
+
+- name: Build SSL domain list
+  set_fact:
+    letsencrypt_certcheck_domains: '{{ letsencrypt_certcheck_domains + hostvars[inv_hostname]["letsencrypt_certcheck_domains"] }}'

playbooks/roles/letsencrypt-config-certcheck/tasks/main.yaml

@@ -2,11 +2,12 @@
   set_fact:
     letsencrypt_certcheck_domains: []
 
-- name: Build SSL domain list
-  set_fact:
-    letsencrypt_certcheck_domains: '{{ letsencrypt_certcheck_domains + hostvars[item]["letsencrypt_certcheck_domains"] }}'
+- name: Debug build SSL domain list
+  include_tasks: build_le_domain_list.yaml
   with_inventory_hostnames:
     - letsencrypt:!disabled
+  loop_control:
+    loop_var: inv_hostname
 
 - name: Write configuration file
   template: