text/template: for loop in go templating?

[joshuacox]

What version of Go are you using (go version)?

go version go1.9.2 linux/amd64

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/thoth/.go"
GORACE=""
GOROOT="/usr/lib/go"
GOTOOLDIR="/usr/lib/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build047417274=/tmp/go-build -gno-record-gcc-switches"
CXX="g++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"

What did you do?

tried to use a for loop in a go template

reaction.mongo_url_big: mongodb://{{ for $mongocount := 0; $mongocount < {{ .Values.mongodbReplicantCount }}; $mongocount++ }}{{ .Values.mongodbReleaseName }}-mongodb-replicaset-{{ $mongocount }}:{{ .Values.mongodbPort }}{{ if $mongocount < {{ .Values.mongodbReplicantCount }} - 1 }},{{ end }}{{ end }}/{{ .Values.mongodbName }}?replicaSet={{ .Values.mongodbReplicaSet }}

I'm using that in a configmap for a kubernetes helm chart here

What did you expect to see?

I wanted go to spit out something like:

  reaction.mongo_url: mongodb://{{ .Values.mongodbReleaseName }}-mongodb-replicaset-0:{{ .Values.mongodbPort }},{{ .Values.mongodbReleaseName }}-mongodb-replicaset-1:{{ .Values.mongodbPort }},{{ .Values.mongodbReleaseName }}-mongodb-replicaset-2:{{ .Values.mongodbPort }}/{{ .Values.mongodbName }}?replicaSet={{ .Values.mongodbReplicaSet }}

What did you see instead?

complaints about for in my template

Why is for not included in the go template actions?

[bradfitz]

Not sure, but we only really use this issue tracker for bugs.

For questions about Go, see https://golang.org/wiki/Questions. Likely somebody there knows about the template package.

[joshuacox]

anyone ending up here in a search can visit the stackoverflow question here