template-functions.md

date	next	prev	title	toc	weight
2016-12-03 15:06:33 +0100	/template/template-filters/	/template/	template functions	true	5

**exists** -- Checks if the key exists. Return false if key is not found.

{% if exists("/key") %}
    value: {{ getv ("/key") }}
{% endif %}

**get** -- Returns the KVPair where key matches its argument.

{% with get("/key") as dat %}
    key: {{dat.Key}}
    value: {{dat.Value}}
{% endwith %}

**gets** -- Returns all KVPair, []KVPair, where key matches its argument.

{% for i in gets("/*") %}
    key: {{i.Key}}
    value: {{i.Value}}
{% endfor %}

**getv** -- Returns the value as a string where key matches its argument or an optional default value.

value: {{ getv("/key") }}

With a default value

value: {{ getv("/key", "default_value") }}

**getvs** -- Returns all values, []string, where key matches its argument.

{% for value in getvs("/*") %}
    value: {{value}}
{% endfor %}

**getenv** -- Retrieves the value of the environment variable named by the key. It returns the value, which will be empty if the variable is not present. Optionally, you can give a default value that will be returned if the key is not present.

export HOSTNAME=`hostname`

hostname: {{getenv("HOSTNAME")}}

With a default value

ipaddr: {{ getenv("HOST_IP", "127.0.0.1") }}

**ls** -- Returns all subkeys, []string, where path matches its argument. Returns an empty list if path is not found.

{% for i in ls("/deis/services") %}
   value: {{i}}
{% endfor %}

**lsdir** -- Returns all subkeys, []string, where path matches its argument. It only returns subkeys that also have subkeys. Returns an empty list if path is not found.

{% for dir in lsdir("/deis/services") %}
   value: {{dir}}
{% endfor %}

**replace** -- Alias for the [strings.Replace](https://golang.org/pkg/strings/#Replace) function.

backend = {{ replace(getv("/services/backend/nginx"), "-", "_", -1) }}

**contains** -- Alias for the [strings.Contains](https://golang.org/pkg/strings/#Contains) function.

{% if contains(getv("/services/backend/nginx"), "something") %}
something
{% endif %}

**printf** -- Alias for the [fmt.Sprintf](https://golang.org/pkg/fmt/#Sprintf) function.

{{ getv (printf ("/config/%s/host_port", dir)) }}

**unixTS** -- Wrapper for [time.Now().Unix()](https://golang.org/pkg/time/#Unix).

{{ unixTS }}

**dateRFC3339** -- Wrapper for [time.Now().Format(time.RFC3339)](https://golang.org/pkg/time/).

{{ dateRFC3339 }}

**lookupIP** -- Wrapper for the [net.LookupIP](https://golang.org/pkg/net/#LookupIP) function. The wrapper returns the IP addresses in alphabetical order.

{% for ip in lookupIP("kube-master") %}
 {{ ip }}
{% endfor %}

**lookupSRV** -- Wrapper for the [net.LookupSRV](https://golang.org/pkg/net/#LookupSRV) function. The wrapper returns the SRV records in alphabetical order.

{% for srv in lookupSRV("xmpp-server", "tcp", "google.com") %}
  target: {{ srv.Target }}
  port: {{ srv.Port }}
  priority: {{ srv.Priority }}
  weight: {{ srv.Weight }}
{% endfor %}

**createMap** -- create a hashMap to store values at runtime. This can be useful if you want to generate json/yaml files.

{% set map = createMap() %}
{{ map.Set("Moin", "Hallo2") }}
{{ map.Set("Test", 105) }}
{{ map | toYAML }}

{% set map2 = createMap() %}
{{ map2.Set("Moin", "Hallo") }}
{{ map2.Set("Test", 300) }}
{{ map2.Set("anotherMap", map) }}
{{ map2 | toYAML }}

The hashmap supports the following methods:

• m.Set("key", value) adds a new value of arbitrary type referenced by "key" to the map
• m.Get("key") get the value for the given "key"
• m.Remove("key") removes the key and value from the map

**createSet** -- create a Set to store values at runtime. This can be useful if you want to generate json/yaml files.

{% set s = createSet() %}
{{ s.Append("Moin") }}
{{ s.Append("Moin") }}
{{ s.Append("Hallo") }}
{{ s.Append(1) }}
{{ s.Remove("Hallo") }}
{{ s | toYAML }}

The set created supports the following methods:

• s.Append("string") adds a new string to the set. Attention - the set is not sorted or the order of appended elements guaranteed.
• s.Remove("string") removes the given element from the set.
• s.Contains("string") check if the given string is part of the set, returns true or false otherwise
• s.SortedSet() return a new list where all elements are sorted in increasing order. This method should be used inside the template with a for-in loop to generate a stable output file not changing order of elements on every run.

{% set s = createSet() %}
{% s.Append("Moin") %}
{% s.Append("Hi") %}
{% s.Append("Hallo") %}

{% for greeting in s %}
{{ geeting }}
{% endfor %}

{% for greeting in s.SortedSet() %}
{{ geeting }}
{% endfor %}

The output of the first loop is not defined, it can be in every order (like Moin Hallo Hi or Hi Hallo Moin and so on) The second loop returns every time Hallo Hi Moin (items sorted as string in increasing order)