helm chart

[kgneng2]

helm 문서

• https://helm.sh/ko/docs/howto/charts_tips_and_tricks/
• https://velog.io/@koseungbin/Helm-Template

템플릿함수

• include : 다른 템플릿으로 부터 가져오는 함수인데.. 결과를 다른 템플릿 함수로 전달한다. value: {{ include "mytpl" . | lower | quote }}
• required : 템플릿 랜더링에 필요한 특정값을 선언하는것이다. empty이면, error message를 준다. value: {{ required "A valid .Values.who entry required!" .Values.who }}

Define

• _ 로 시작하는 파일 또는 template 에서 특정 항목들을 정의할 수 있다. (_helph.tpl )
• 전역적으로 선언되어,여러 template 에서 include 해 참조 가능

  {{ define "MY.NAME" }}  // 외부에서 "MY.NAME" 으로 참조하므로, 고유한 prefix 를 붙일 것으로 권장
  # body of template here
  {{ end }}

Template

• define 으로 선언한 'mychart.labels' 을 추가
• template 은 pipeline으로 함수 호출 안되기 때문에 indent 에 유의(정의하는 쪽에서 indent 를 설정, 사용하는 측은 변경 어려움)
• template 보다는 include 권장
• template 두 번째 인자(.) 는 "mychart.labels" 내부에서의 스코프 지정 {{ template "mychart.labels" . }}

Include

• template 과 유사 하나 pipeline 이용해 다중으로 함수 호출 가능하여, 사용측에서 indent 설정 가능
• include 두 번째 인자(.) 는 "mychart.labels" 내부에서의 스코프 지정 {{ include "mychart.labels" . | nindent 4 }}

go template 문서

https://pkg.go.dev/text/template#hdr-Text_and_spaces

{{/* a comment */}}
{{- /* a comment with white space trimmed from preceding and following text */ -}}
    A comment; discarded. May contain newlines.
    Comments do not nest and must start and end at the
    delimiters, as shown here. 공백 제거 하는 것 

{{pipeline}}
    The default textual representation (the same as would be
    printed by fmt.Print) of the value of the pipeline is copied
    to the output.

{{if pipeline}} T1 {{end}}
    If the value of the pipeline is empty, no output is generated;
    otherwise, T1 is executed. The empty values are false, 0, any
    nil pointer or interface value, and any array, slice, map, or
    string of length zero.
    Dot is unaffected. 

{{if pipeline}} T1 {{else}} T0 {{end}}
    If the value of the pipeline is empty, T0 is executed;
    otherwise, T1 is executed. Dot is unaffected.

{{if pipeline}} T1 {{else if pipeline}} T0 {{end}}
    To simplify the appearance of if-else chains, the else action
    of an if may include another if directly; the effect is exactly
    the same as writing
        {{if pipeline}} T1 {{else}}{{if pipeline}} T0 {{end}}{{end}}

{{range pipeline}} T1 {{end}}
    The value of the pipeline must be an array, slice, map, or channel.
    If the value of the pipeline has length zero, nothing is output;
    otherwise, dot is set to the successive elements of the array,
    slice, or map and T1 is executed. If the value is a map and the
    keys are of basic type with a defined order, the elements will be
    visited in sorted key order.

{{range pipeline}} T1 {{else}} T0 {{end}}
    The value of the pipeline must be an array, slice, map, or channel.
    If the value of the pipeline has length zero, dot is unaffected and
    T0 is executed; otherwise, dot is set to the successive elements
    of the array, slice, or map and T1 is executed.

{{template "name"}}
    The template with the specified name is executed with nil data.

{{template "name" pipeline}}
    The template with the specified name is executed with dot set
    to the value of the pipeline.

{{block "name" pipeline}} T1 {{end}}
    A block is shorthand for defining a template
        {{define "name"}} T1 {{end}}
    and then executing it in place
        {{template "name" pipeline}}
    The typical use is to define a set of root templates that are
    then customized by redefining the block templates within.

{{with pipeline}} T1 {{end}}
    If the value of the pipeline is empty, no output is generated;
    otherwise, dot is set to the value of the pipeline and T1 is
    executed.

{{with pipeline}} T1 {{else}} T0 {{end}}
    If the value of the pipeline is empty, dot is unaffected and T0
    is executed; otherwise, dot is set to the value of the pipeline
    and T1 is executed.