I am wondering if there is a more efficient way to exclude any yaml keys which do not have a value set.
My current approach is to wrap each key in an if statement...
container:
spec:
{{- if values.spec.x }}
x: {{ values.spec.x }}
{{- end}}
{{- if values.spec.y }}
y: {{ values.spec.y }}
{{- end}}
{{- if values.spec.z }}
z: {{ values.spec.z }}
{{- end}}
e.g.
for each child of container.spec:
if the value != null:
include as child of spec
else:
exclude from spec
I thought about wrapping the above in a _helper.tpl function to try to keep the main template tidy, but it would still include writing multiple if statements.
Is there a better way of doing the above?
Thanks!
You can directly translate that pseudocode into Helm chart logic. The trick is that a Go template range loop is basically equivalent to a "for" loop in most languages. So:
container:
spec:
{{- range $key, $value := .Values.spec }}
{{- if ne $value nil }}
{{ $key }}: {{ $value }}
{{- end }}
{{- end }}
If you can just omit the unused keys from the values, then this becomes simpler and safer. Helm includes a lightly-documented toYaml function that will render an arbitrary structure as YAML, but you can't really do any filtering or other preprocessing before writing it out.
container:
spec:
{{ .Values.spec | toYaml | indent 4 }}
Related
In a helm chart want to iterate over a map that contains structured values.
I do know how to iterate over a map with simple string values. I also can iterate over an array that contains structured values (not shown here). But I did not manage to iterate over a map that contains structured values.
This is my directory structure containing 3 files:
templates/test.yaml
Chart.yaml
values.yaml
A simple file Chart.yaml (just for completing the showcase):
---
apiVersion: v1
appVersion: "1.0"
description: A Helm chart for Kubernetes
name: foochart
version: 0.1.0
The file values.yaml with a map that contains simple string values (label) and one that contains structured values (label1):
---
label:
fook: foo
bark: bar
label1:
fook:
name: foo
value: foo1
bark:
name: bar
value: bar2
This template test.yaml works:
---
env:
{{- range $k, $v := .Values.label }}
- name: {{ $k }}
value: {{ $v }}
{{- end }}
But when I substitute .Values.label by .Values.label1, it produces no output.
This is my command for testing:
helm template foochart
Question: Is it possible to process a map with structured values? I would like to use something like $v.name. If yes, how can I do that?
You can in fact use syntax like $v.name, if you know that $v is a variable holding an object.
env:
{{- range $k, $v := .Values.label1 }}
- name: {{ $k }}_{{ $v.name }}
value: {{ $v.value }}
{{- end }}
If you know that it has exactly the syntax you want, there is an underdocumented toYaml function that takes an arbitrary object and returns it as unindented YAML. In your example, each of the values has the form of an env: item, and if you know (or specify) that, you can write out literally:
env:
{{- range .Values.label1 }}
- {{ . | toYaml | indent 4 | trim }}
{{- else }}
[]
{{- end }}
(In this last example: I'm not assigning a variable, so . is temporarily reassigned to each value in the map, and the keys are lost; for each item, I convert it to YAML, indent it by 4 spaces, but then trim out leading and trailing whitespace; and if there are no values, I explicitly write out an empty list.)
It's usually easier to specify a format you want your values to be in, and work with that. If you for some reason can't be sure which form you have, the template language includes functions to test on a value's type, so in principle you can test:
env:
{{- range $k, $v := .Values.labelN }}
{{- if kindIs "string" $v }}
- name: {{ $k }}
value: {{ $v }}
{{- else }}
- name: {{ $v.name }}
value: {{ $v.value }}
{{- end }}
{{- else }}
[]
{{- end }}
I'm trying to pass a dictionary from one helm template to another but it's resolved to null inside the called template.
Calling template - deployment.yaml
Called template - storageNodeAffinity
I see myDict printed as map inside deployment.yaml but inside storageNodeAffinity it's printed as null.
Eventually I need to pass nodeAffn from the values file.
deployment.yaml
{{- $myDict := dict "cpu" "amd" }}
{{- include "storageNodeAffinity" $myDict | indent 6 }}
{{printf "%q" $myDict}}
storage-affinity.tpl
{{- define "storageNodeAffinity" }}
{{/* {{- $myDict := dict "cpu" "amd" }}*/}}
{{printf "%q" .myDict}}
{{- range $key, $val := .myDict }}
- key: {{ $key }}
operator: In
values:
- {{ $val }}
{{- end }}
{{- end }}
values.yaml
nodeAffn:
disktype: "ssd"
cpu: intel
When you call a template
{{- include "storageNodeAffinity" $myDict -}}
then within the template whatever you pass as the parameter becomes the special variable .. That is, . is the dictionary itself; you don't need to use a relative path to find its values.
{{- define "storageNodeAffinity" }}
{{/* ., not .myDict */}}
{{printf "%q" .}}
{{- range $key, $val := . }}...{{ end -}}
{{- end -}}
I figured it out. The trick is to pass context of the parent variable for the variable you want to use in the called template. So here I'm passing "csAffn" as context and then using "nodeAffn" inside this context, in the called template (_additionalNodeAffinity)
_additionalNodeAffinity.tpl
{{- define "additionalNodeAffinity" }}
{{- range $key, $val := .nodeAffn }}
- key: {{ $key }}
operator: In
values:
- {{ $val }}
{{- end }}
{{- end }}
deployment.yaml
{{- include "additionalNodeAffinity" ( .Values.csAffn )
values.yaml
csAffn:
nodeAffn:
disktype: "ssd"
cpu: "intel"
I am trying to define a collection (dict), and I would like to add a new line on each definition (for readability), Eg:
{{ $deployment := dict
"Release" .Release
"Chart" .Chart
"Values" .Values }}
But when I do this, helm respond a parse error :
Error: parse error in "XXX": template: XXX:2: unclosed action
Error: UPGRADE FAILED: parse error in "XXX": template: XXX:2: unclosed action
Is there a way in HELM to do this?
I achieved this by defining the dict first and then setting one key per line.
{{- $myDict := dict "" "" -}}
{{- $_ := set $myDict "myKey1" "myValue1" -}}
{{- $_ := set $myDict "myKey2" "myValue2" -}}
{{- $_ := set $myDict "myKey3" "myValue3" -}}
{{- $_ := set $myDict "myKey4" "myValue4" -}}
Bonus Tip: Since dict get function is available seemingly in only helm3 and later, you can use this hack to get a value from a dict to a string.
{{/* Hack needed until helm 3 which has 'get' for 'dict' */}}
{{- $myValue3Var := pluck "myKey3" $myDict | first -}}
TLDR;
It's impossible to declare dict in multiline way, like with Perl fat comma operator.
Please check the reference of "Sprig: Template functions for Go templates."
Instead you could use this sort of hacky way to achieve similar result:
Keep each key value pair in separate line, in Global Values file for readability:
# values.yaml
--
global:
someMap:
coffee: robusta
origin: Angola
crema: yes
Define helper template in _helpers.tpl:
{{- define "mychart.labels.standard"}}
{{- $global := default (dict) .Values.global.someMap -}}
Release: {{ .Release.Name | quote }}
Chart: {{ .Chart.Name }}
Values:
{{- $global := default (dict) .Values.global.someMap -}}
{{- range $key, $value := $global }}
{{ $key }}: {{ $value }}
{{- end }}
{{- end -}}
Include it in another template:
helm_data:
{{- $global := default (dict) .Values.global -}}
{{- range $key, $value := $global }}
{{ $key }}: {{ $value }}
{{- end }}
{{ include "mychart.labels.standard" . | nindent 0 -}}
Render it to verify the result (helm template --name dict-chart .)
---
# Source: mychart/templates/data_type.yaml
helm_data:
someMap: map[crema:true origin:Angola coffee:robusta]
Release: "dict-chart"
Chart: mychart
Values:
coffee: robusta
crema: true
origin: Angol
It seems it's impossible to do so. The Helm templating system is basically the Go templating system. As stated in the Go templating docs:
Except for raw strings, actions may not span newlines, although comments can.
For people coming across this question, this functionality works in recent versions of HELM. For me, OPs example works as-is (Helm v3.8.2).
(I came across this question myself due to a mismatched ) in my template.)
I am doing this now:
value: {{ required "A valid .Values.foo entry required!" .Values.foo }}
But to give this same message for all required values in the templates is cumbersome and clutters the templates in my opinion.
Is there a better way where we could define it outside the template \ or a cleaner way to do it within the template itself?
You could do something by taking advantage of range and the fact that null will fail the required check. So in your values.yaml you could have this section for required env vars:
reqEnv:
- name: "VAR1"
value: null
- name: "VAR2"
value: null
And in the env section of the Deployment you then have:
{{- range .Values.reqEnv }}
{{ .name }}: {{ required "A value must be entered for all reqEnv entries" .value }}
{{- end }}
Then the user gets an error unless they set all required values of the reqEnv section in their values file or as paramters. Unfortunately what you lose by doing this is the detail of which var is missing. This could be why the official helm charts seem to prefer using required in the way that you already are.
Define the required values on top of your manifest as variables utilizing the required function.
E.g. deployment.yaml:
{{- $name := .Values.name | required ".Values.name is required." -}}
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: {{ $name }}
....
You can use helm lint with --strict flag to check undefined values
$ helm lint --strict .
==> Linting .
[INFO] Chart.yaml: icon is recommended
[ERROR] templates/: render error in "mychart/templates/service.yaml": template: mychart/templates/service.yaml:10:19: executing "mychart/templates/service.yaml" at <.Values.foo>: map has no entry for key "foo"
Error: 1 chart(s) linted, 1 chart(s) failed
To expose name of missing item to required text you can do something like this:
{{- range $field, $my_key := $data }}
{{- if hasKey $dic1 $my_key }}
{{ $field }}: {{ index $dic1 $my_key | b64enc}}
{{- else if hasKey $dic2 $my_key }}
{{ $field }}: {{ index $dic2 $my_key | b64enc}}
{{- else }}
{{ $field }}: {{ required (printf "key %s is missing" $my_key) nil }}
{{- end }}
{{- end }}
I've come up with an alternative hack trying to solve this problem. It's questionable whether this is actually any better that the built in solution, but I thought it might be worth noting down here as an option.
Add a function to your _helpers.tpl (or wherever):
{{/*
Require and include a value
*/}}
{{- define "require" -}}
{{- $scope := index . 0 -}}
{{- $name := index . 1 -}}
{{required (print "Missing required value: " $name) (index $scope "Values" $name)}}
{{- end}}
Then in your template call it with:
value: {{ include "require" (list . "foo") }}
If a value is missing, it errors with message:
Missing required value: foo
Otherwise, it inserts the value.
Edit: To make this work for nested values, you need a slightly more complex helper:
{{/*
Index a nested component
*/}}
{{- define "indexNested" -}}
{{- $message := index . 0 -}}
{{- $object := index . 1 -}}
{{- $path := (mustRegexSplit "\\." (index . 2) -1) -}}
{{- range $path -}}
{{- if not $object -}}
{{ fail $message }}
{{- end -}}
{{- $object = index $object . -}}
{{- end -}}
{{ required $message $object }}
{{- end}}
{{/*
Require and include a value
*/}}
{{- define "require" -}}
{{- $scope := index . 0 -}}
{{- $name := index . 1 -}}
{{ include "indexNested" (list (print "Missing required value: " $name) $scope.Values $name) }}
{{- end}}
Now you can access the foo.bar value with:
{{ include "require" (list . "foo.bar") }}
Below is my case:
{{- $v := (.Files.Get "values-productpage.yaml") | fromYaml }}.
spec:
{{- range $key, $value := $v.containers }}
containers:
- name: {{ $value.name }}
image: {{.Values.productpage_image}}:latest
Here when reaching .Values.productpage_image, it reports: can't evaluate field productpage_image in type interface {}.
Is there any usage error here? Why can I not use .Values.xxx in this loop? If I move the .Values to the first line, there is no error.
You can simply use $ to get to the root scope
Without defining what $root is, you can references .Values as $.Values from within a loop, or any other scope.
Source: https://github.com/kubeapps/kubeapps/pull/1057
It's because range changes a scope (see detailed description here https://github.com/helm/helm/blob/master/docs/chart_template_guide/control_structures.md#looping-with-the-range-action).
You can assign .Values.productpage_image to the variable outside the range and use inside.
As #abinet explained properly about the reason, I'll share my solution for that( which helped me a lot, and I hope that will save you time):
First, I saved the scope:
{{- $root := . -}}
and after that , I called the .Value inside the loop context like this:
{{ $root.Values.data }}
so basically , you code should be look like:
{{- $root := . -}}
{{- $v := (.Files.Get "values-productpage.yaml") | fromYaml }}.
spec:
{{- range $key, $value := $v.containers }}
containers:
- name: {{ $value.name }}
image: {{$root.Values.productpage_image}}:latest