I have top level chart and one of the subcharts. In subchart I want to use variables that defined in level chart, and if it is not found - use default value.
I have code like this in one of deployment definitions in my subchart
name: {{tpl .Values.global.my.GlobalValue .}}
where Values.global.my.GlobalValue - is parameter from top level chart.
Problem is when I try to install only subchart - I am failing, I need some defaults.
I tried to puth like below and it is not working
name: {{default defaultName tpl .Values.global.my.GlobalValue .}}
name: {{tpl .Values.global.my.GlobalValue . | defaultName}}
Could you please advise the correct way to do that.
As per Using the default function:
One function frequently used in templates is the default function:
default DEFAULT_VALUE GIVEN_VALUE. This function allows you to specify
a default value inside of the template, in case the value is omitted.
You should use:
name: {{ .Values.global.my.GlobalValue | default "defaultName" | quote }}
Related
I'm trying to use a Helm named template that I plan to include with several different contexts, and the template has many values that are the same for all contexts.
Whenever I pass a context to template or include to invoke the named template, the references to .Values do not work, which is understandable because I'm explicitly setting a lower context.
In the Helm documentation for with, it claims there is a "global" variable $ that will allow reference to the global .Values, e.g., {{ $.Values... }}. This does not work (the example below shows the error).
I've also tried defining variables (using :=) and "enclosing" the include inside that variable definition (via indentation - I don't know if it matters) to make that variable available within the named template, but this doesn't work either.
I've also tried putting these in "globals" as described here which is more of a subchart thing and this doesn't work either.
So, I'm out of Helm tricks to make this work and will sadly have to re-define these many same variable many times - which makes the entire named template solution a bit less elegant - or just go back to having largely duplicate partially-parameterized templates.
What am I missing?
$ helm version
Client: &version.Version{SemVer:"v2.9+unreleased", GitCommit:"", GitTreeState:"clean"}
Values.yaml:
---
commonSetting1: "common1"
commonSetting2: "common2"
context1:
setting1: "c1s1"
setting2: "c1s2"
context2:
setting1: "c2s1"
setting2: "c2s2"
deployment.yaml:
---
{{- define "myNamedTemplate" }}
- name: {{ .setting1 }}
image: {{ $.Values.commonSetting1 }}
{{- include "myNamedTemplate" .Values.context1 }}
{{- include "myNamedTemplate" .Values.context2 }}
$ helm template test-0.1.0.tgz
Error: render error in "test/templates/deployment.yaml": template: test/templates/deployment.yaml:7:4: executing "test/templates/deployment.yaml" at <include "myNamedTemp...>: error calling include: template: test/templates/deployment.yaml:4:19: executing "myNamedTemplate" at <$.Values.commonSetti...>: can't evaluate field commonSetting1 in type interface {}
When I do this, I tend to explicitly pass in the top-level context object as a parameter. This gets a little tricky because the Go text/template templates only take a single parameter, so you need to use the (Helm/Sprig) list function to package multiple parameters together, and then the (standard text/template) index function to unpack them.
The template definition would look like:
{{- define "myNamedTemplate" }}
{{- $top := index . 0 }}
{{- $context := index . 1 }}
- name: {{ $context.setting1 }}
image: {{ $top.Values.commonSetting1 }}
{{ end }}
When you invoke it, you would then need to explicitly pass the current context as a parameter:
{{ include "myNamedTemplate" (list . .Values.context1) }}
Is it possible to use a variable inside the template define function? I attempted to wrap the variable in brackets but it seems to fail. Example
{{- define {{ .Chart.Name }}.deployment -}}
The names of template functions are always fixed strings. (This is common with almost all programming languages.) Since these names don't appear anywhere in the rendered YAML, it doesn't really matter what they're called. The only place there's a potential conflict is if your chart includes other subcharts as dependencies, or is included as a subchart; in that case all template functions share the same function namespace.
A common convention is to name templates following the current chart name; that is, matching the fixed string in the Chart.yaml file
{{- define "mychart.deployment" -}}
Using the Helm include function you can call templates with a dynamic name, but this is a somewhat unusual use.
values.yaml
global:
key: {}
deployment: appdeployv1
If you were to expand the name of the chart, you would do it like this
_helpers.tpl
{{- define "key.name" -}}
{{- default .Chart.Name .Values.deployment | trunc 63 | trimSuffix "-" -}}
{{- end -}}
That's all I can understand from your question. I hope this helps. You can try exploring docs and check Declaring and using templates with define and template heading for detailed info.
Using Helm, I was under the impression default would be the fallback if a variable is not defined. However, it doesn't appear Helm can get to values in sub-object hashes:
type: {{ default "NodePort" .Values.fpm.service.type }}
If .Values.fpm.service or service.type is not defined, it should use 9000.
However, attempting to template this throws a nil pointer error:
<.Values.fpm.service.type>: nil pointer evaluating interface {}.type
Is there a way to simply perform this level of variable testing? Or am I subjected to an if/else test?
The intent of this is to optionally define .fpm.service (and [..].type) within your values.yaml file.
(I'm building a Helm Library chart to handle optional definitions by main charts)
According to the official Helm doc (Using Default Function), the syntax is different and you should use it this way:
type: {{ .Values.fpm.service.type | default "NodePort" | quote }}
Doesn't look like there's really a good way to stop Helm from trying to dive into non-existing objects. I moved into a single line if condition, and it worked:
type: {{ if .Values.fpm.service -}} {{ .default "NodePort" .Values.fpm.service.type | quote }} {{- else -}} "NodePort" {{- end }}
This way, I check if fpm.service exists first, before trying .type check. It works, whether .service and .service.type is or is not defined.
I am creating a helm chart in which I want to specify a default for a value using a template function. Specifically I want to either use the override value image.name, or default to the template function chart.name:
{{ .Values.image.name | default include chart.name . }}
But when linting the chart I have the following error:
[ERROR] templates/: render error in "chart/templates/deployment.yaml": template: chart/templates/deployment.yaml:22:81: executing "chart/templates/deployment.yaml" at <include>: wrong number of args for include: want 2 got 0
Is it possible to use an included template function as the default value? Or can I only use literals?
You can. Just enclose your include statement in parentheses:
{{ .Values.image.name | default (include "chart.name" .)}}
Please see using the default function
I'm building a helm chart for my application, and I'm using stable/nginx-ingress as a subchart. I have a single overrides.yml file that contains (among other overrides):
nginx-ingress:
controller:
annotations:
external-dns.alpha.kubernetes.io/hostname: "*.{{ .Release.Name }}.mydomain.com"
So, I'm trying to use the release name in the overrides file, and my command looks something like: helm install mychart --values overrides.yml, but the resulting annotation does not do the variable interpolation, and instead results in something like
Annotations: external-dns.alpha.kubernetes.io/hostname=*.{{ .Release.Name }}.mydomain.com
I installed the subchart by using helm fetch, and I'm under the (misguided?) impression that it would be best to leave the fetched thing as-is, and override values in it - however, if variable interpolation isn't available with that method, I will have to put my values in the subchart's values.yaml.
Is there a best practice for this? Is it ok to put my own values in the fetched subchart's values.yaml? If I someday helm fetch this subchart again, I'll have to put those values back in by hand, instead of leaving them in an untouched overrides file...
Thanks in advance for any feedback!
I found the issue on github -- it is not supported yet:
https://github.com/kubernetes/helm/issues/2133
Helm 3.x (Q4 2019) now includes more about this, but for chart only, not for subchart (see TBBle's comment)
Milan Masek adds as a comment:
Thankfully, latest Helm manual says how to achieve this.
The trick is:
enclosing variable in " or in a yaml block |-, and
then referencing it in a template as {{ tpl .Values.variable . }}
This seems to make Helm happy.
Example:
$ cat Chart.yaml | grep appVersion
appVersion: 0.0.1-SNAPSHOT-d2e2f42
$ cat platform/shared/t/values.yaml | grep -A2 image:
image:
tag: |-
{{ .Chart.AppVersion }}
$ cat templates/deployment.yaml | grep image:
image: "{{ .Values.image.repository }}:{{ tpl .Values.image.tag . }}"
$ helm template . --values platform/shared/t/values.betradar.yaml | grep image
image: "docker-registry.default.svc:5000/namespace/service:0.0.1-SNAPSHOT-d2e2f42"
imagePullPolicy: Always
image: busybox
Otherwise there is an error thrown..
$ cat platform/shared/t/values.yaml | grep -A1 image:
image:
tag: {{ .Chart.AppVersion }}
1 $ helm template . --values platform/shared/t/values.yaml | grep image
Error: failed to parse platform/shared/t/values.yaml: error converting YAML to JSON: yaml: invalid map key: map[interface {}]interface {}{".Chart.AppVersion":interface {}(nil)}
For Helm subchart, TBBle adds to issue 2133
#MilanMasek 's solution won't work in general for subcharts, because the context . passed into tpl will have the subchart's values, not the parent chart's values.
!<
It happens to work in the specific example this ticket was opened for, because .Release.Name should be the same in all the subcharts.
It won't work for .Chart.AppVersion as in the tpl example.
There was a proposal to support tval in #3252 for interpolating templates in values files, but that was dropped in favour of a lua-based Hook system which has been proposed for Helm v3: #2492 (comment)
That last issue 2492 include workarounds like this one:
You can put a placeholder in the text that you want to template and then replace that placeholder with the template that you would like to use in yaml files in the template.
For now, what I've done in the CI job is run helm template on the values.yaml file.
It works pretty well atm.
cp values.yaml templates/
helm template $CI_BUILD_REF_NAME ./ | sed -ne '/^# Source:
templates\/values.yaml/,/^---/p' > values.yaml
rm templates/values.yaml
helm upgrade --install ...
This breaks if you have multiple -f values.yml files, but I'm thinking of writing a small helm wrapper that runs essentially runs that bash script for each values.yaml file.
fsniper illustrates again the issue:
There is a use case where you would need to pass deployment name to dependency charts where you have no control.
For example I am trying to set podAffinity for zookeeper. And I have an application helm chart which sets zookeeper as a dependency.
In this case, I am passing pod antiaffinity to zookeeper via values. So in my apps values.yaml file I have a zookeeper.affinity section.
If I had the ability to get the release name inside the values yaml I would just set this as default and be done with it.
But now for every deployment I have to override this value, which is a big problem.
Update Oct. 2022, from issue 2133:
lazychanger proposes
I submitted a plugin to override values.yaml with additional templates.
See lazychanger/helm-viv: "Helm-variable-in-values" and its example.