From 1f00d0c2cfeda690060522ac9da0b41a6b6a434c Mon Sep 17 00:00:00 2001
From: Michael Mol <mikemol@gmail.com>
Date: Mon, 12 Jun 2017 17:30:22 -0400
Subject: [PATCH 1/2] Add flexjoin macro

The flexjoin() macro simplifies support for mergable and composable
structures. All three of these data structures will result in the string
'a s d f'. The third structure, using dicts, also supports pillar merging.

- 'a s d f'

- [ a, s, d, f]

- { a: ~, s: ~, d: ~, f: ~}
---
 .../default/etc/zabbix/zabbix_agentd.conf.jinja     | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/zabbix/files/default/etc/zabbix/zabbix_agentd.conf.jinja b/zabbix/files/default/etc/zabbix/zabbix_agentd.conf.jinja
index a71f338e..d27e9772 100644
--- a/zabbix/files/default/etc/zabbix/zabbix_agentd.conf.jinja
+++ b/zabbix/files/default/etc/zabbix/zabbix_agentd.conf.jinja
@@ -1,4 +1,17 @@
 {% from "zabbix/map.jinja" import zabbix with context -%}
+{# Consider a value, keep a string, join a list, or join a dict's sorted keys -#}
+{% macro flexjoin(srcval, sep=' ') -%}
+  {# If it's a simple value, emit it. -#}
+  {% if srcval is string or srcval is number -%}
+    {{ srcval -}}
+  {# If it's a dict, take the keys (for pillar merging), sort them (for stability), flexjoin them. -#}
+  {% elif srcval is mapping -%}
+    {{ flexjoin( srcval.keys()|sort, sep) -}}
+  {# If it's a list, join it. -#}
+  {% else -%}
+    {{ srcval|join(sep) -}}
+  {% endif -%}
+{% endmacro -%}
 {% set settings = salt['pillar.get']('zabbix-agent', {}) -%}
 # Managed by saltstack
 # do not edit this file.

From af7d74148b268f31804dbf47258f0ba30645c462 Mon Sep 17 00:00:00 2001
From: Michael Mol <mikemol@gmail.com>
Date: Mon, 12 Jun 2017 17:50:01 -0400
Subject: [PATCH 2/2] Support composable Host Metadata

Take advantage of Salt's pillar merging to compose host metadata; in
this way, we can apply multiple roles to a node and have the Zabbix
agent report the combination of applied roles to the Zabbix server. In
turn, we can automatically apply role-specific templates through the
Zabbix server's host registration process.

The following pillar data structures are all valid:

- zabbix-agent: # Not mergable
    hostmetadata: my-host-metadata # Not mergable

- zabbix-agent: # Not mergable; Zabbix cannot merge lists
    hostmetadata:
      - metadata component 1
      - metadata component 2
      - metadata component 3

- zabbix-agent: # Supports pillar merging
    hostmetadata:
      metadata component 1:
      metadata component 2:
      metadata component 3:
---
 zabbix/files/default/etc/zabbix/zabbix_agentd.conf.jinja | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/zabbix/files/default/etc/zabbix/zabbix_agentd.conf.jinja b/zabbix/files/default/etc/zabbix/zabbix_agentd.conf.jinja
index d27e9772..684dc64d 100644
--- a/zabbix/files/default/etc/zabbix/zabbix_agentd.conf.jinja
+++ b/zabbix/files/default/etc/zabbix/zabbix_agentd.conf.jinja
@@ -143,7 +143,7 @@ Hostname={{ settings.get('hostname', salt['grains.get']('id')) }}
 #	An agent will issue an error and not start if the value is over limit of 255 characters.
 #	If not defined, value will be acquired from HostMetadataItem.
 #
-{% if settings.get('hostmetadata', false) %}HostMetadata={{ settings.get('hostmetadata') }}{% endif %}
+{% if settings.get('hostmetadata', false) %}HostMetadata={{ flexjoin(settings.get('hostmetadata'), ' ') }}{% endif %}
 
 ### Option: HostMetadataItem
 #	Optional parameter that defines an item used for getting host metadata.