HAProxy configuration generated from consul via consul-template to generate frontend/backend services across multiple datacenters

haproxy-multi-dc.ctmpl

##
## NOTE: Configuration generated by consul-template
## local changes will be overwritten.
##{{$myDc := key "env/dc"}}

## lb/haproxy/global
global{{range ls "lb/haproxy/global"}}{{if ne .Key "rawText"}}
    {{.Key}} {{.Value}}
{{- end}}{{end -}}
{{range $key, $pairs := tree "lb/haproxy/global" | byKey}}{{range $pair := $pairs}}
    {{$key}} {{.Key}}{{if ne .Value ""}} {{.Value}}{{end}}
{{- end}}{{end -}}
{{with $rawText := key "lb/haproxy/global/rawText"}}{{if ne $rawText ""}}
    ## lb/haproxy/defaults/rawText
{{$rawText}}
    ## end raw
{{- end}}{{end}}

## lb/haproxy/defaults
defaults{{range ls "lb/haproxy/defaults"}}{{if ne .Key "rawText"}}
    {{.Key}} {{.Value}}
{{- end}}{{end -}}
{{range $key, $pairs := tree "lb/haproxy/defaults" | byKey}}{{range $pair := $pairs}}
    {{$key}} {{.Key}}{{if ne .Value ""}} {{.Value}}{{end}}
{{- end}}{{end -}}
{{with $rawText := key "lb/haproxy/defaults/rawText"}}{{if ne $rawText ""}}
    ## lb/haproxy/defaults/rawText
{{$rawText}}
    ## end raw
{{- end}}{{end}}

## lb/haproxy/frontend/main
frontend main{{range ls "lb/haproxy/frontend/main"}}{{if ne .Key "rawText"}}
    {{.Key}} {{.Value}}
{{- end}}{{end -}}
{{range ls "lb/haproxy/frontend/main/bind"}}
    bind {{.Key}}{{if ne .Value ""}} {{.Value}}{{end}}
{{- end -}}
{{with $rawText := key "lb/haproxy/frontend/main/rawText"}}{{if ne $rawText ""}}
    ## lb/haproxy/frontend/main/rawText
{{$rawText}}
{{- end}}{{end -}}
{{range $dcIdx, $dcName := datacenters -}}
{{$dcAtName := printf "@%s" $dcName -}}
{{range services $dcAtName -}}
{{$svcNameLoc := printf "%s@%s" .Name $dcName -}}
{{if in .Tags "proxy-unique" -}}
{{if service $svcNameLoc -}}
{{with index (service $svcNameLoc) 0}}
    ## unique {{.ID}}{{$dcAtName}}
    acl path_{{.ID}} path_beg /{{.ID}}/
    use_backend app_{{.ID}} if path_{{.ID}}
{{- end}}{{end}}{{end -}}
{{if in .Tags "proxy-standard" -}}
{{if service $svcNameLoc -}}
{{with index (service $svcNameLoc) 0 -}}
{{$myServiceName := printf "%s@%s" .Name $myDc -}}
{{if ne $dcName $myDc -}}
{{if service $myServiceName}}{{/* local service exists - skip remote service */}}{{else}}
    ## standard {{.Name}}{{$dcAtName}}
    acl path_{{.Name}} path_beg /{{if in .Tags "proxy-dash2dots"}}{{.Name | replaceAll "-" "."}}{{else}}{{.Name}}{{end}}/
    use_backend app_{{.Name}} if path_{{.Name}}
{{- end -}}
{{else}}{{/* no local service - use remote */}}
    ## standard {{.Name}}{{$dcAtName}}
    acl path_{{.Name}} path_beg /{{if in .Tags "proxy-dash2dots"}}{{.Name | replaceAll "-" "."}}{{else}}{{.Name}}{{end}}/
    use_backend app_{{.Name}} if path_{{.Name}}
{{- end}}{{end}}{{end}}{{end}}{{end}}{{end}}
    ## default backend provides root
    default_backend rootBackend

## default backend
backend rootBackend
    mode http{{range $dcIdx, $dcName := datacenters -}}
{{$dcAtName := printf "@%s" $dcName -}}
{{range services $dcAtName -}}
{{$svcNameLoc := printf "%s@%s" .Name $dcName -}}
{{if in .Tags "proxy-root" -}}
{{if service $svcNameLoc -}}
{{range service $svcNameLoc}}
    server {{.ID}}:{{$dcName}} {{.Address}}:{{.Port}}{{if in .Tags "proxy-check"}} check{{end}}{{if in .Tags "proxy-ssl"}} ssl verify none{{end}}{{if ne $myDc $dcName}} backup{{end}}
{{- end}}{{end}}{{end}}{{end}}{{end}}
{{range $dcIdx, $dcName := datacenters -}}
{{$dcAtName := printf "@%s" $dcName -}}
{{range services $dcAtName -}}
{{$svcNameLoc := printf "%s@%s" .Name $dcName -}}
{{if in .Tags "proxy-unique" -}}
{{if service $svcNameLoc -}}
{{with index (service $svcNameLoc) 0}}
## unique backend {{.ID}}
backend app_{{.ID}}
    mode http
{{- if in .Tags "proxy-internal"}}{{with $enaInternal := key "lb/haproxy/misc/enaInternal" -}}
{{if ne $enaInternal ""}}
{{$enaInternal}}
{{- end}}{{end}}{{end -}}
{{if in .Tags "proxy-nostrip" -}}
{{/* do nothing */}}{{else}}
    reqrep ^(GET|PUT|POST|DELETE|PATCH|OPTIONS)\ /{{.ID}}/(.*) \1\ /\2
{{- end}}
    server {{.ID}}:{{$dcName}} {{.Address}}:{{.Port}}{{if in .Tags "proxy-check"}} check{{end}}{{if in .Tags "proxy-ssl"}} ssl verify none{{end -}}
{{end}}{{end}}{{end}}{{end}}{{end}}
{{range $dcIdx, $dcName := datacenters -}}
{{$dcAtName := printf "@%s" $dcName -}}
{{range services $dcAtName -}}
{{$svcNameLoc := printf "%s@%s" .Name $dcName -}}
{{if in .Tags "proxy-standard" -}}
{{if service $svcNameLoc -}}
{{$myServiceName := printf "%s@%s" .Name $myDc -}}
{{if ne $dcName $myDc -}}
{{if service $myServiceName -}}
{{/* do nothing */}}{{else}}{{/* services not registered locally */}}
## standard backend {{.Name}}
backend app_{{.Name}}
    mode http
{{- if in .Tags "proxy-rewrite-net-cookie"}}{{with $rewriteCookie := key "lb/haproxy/misc/rewriteNetCookie" -}}
{{if ne $rewriteCookie ""}}
{{$rewriteCookie}}
{{- end}}{{end}}{{end -}}
{{if in .Tags "proxy-internal"}}{{with $enaInternal := key "lb/haproxy/misc/enaInternal" -}}
{{if ne $enaInternal ""}}
{{$enaInternal}}
{{- end }}{{end}}{{end -}}
{{if in .Tags "proxy-nostrip" -}}
{{/* do nothing */}}{{else}}
    reqrep ^(GET|PUT|POST|DELETE|PATCH|OPTIONS)\ /{{if in .Tags "proxy-dash2dots"}}{{.Name | replaceAll "-" "."}}{{else}}{{.Name}}{{end}}/(.*) \1\ /\2
{{- end}}
    balance roundrobin{{$svcName := .Name -}}
{{range $dcIdx2, $dcName2 := datacenters -}}
{{$svcNameLoc2 := printf "%s@%s" $svcName $dcName2 -}}
{{if service $svcNameLoc2 -}}
{{range service $svcNameLoc2}}
    server {{.ID}}:{{$dcName2}} {{.Address}}:{{.Port}}{{if in .Tags "proxy-check"}} check{{end}}{{if in .Tags "proxy-ssl"}} ssl verify none{{end}}{{if ne $myDc $dcName2}} backup{{end}}
{{- end}}{{end}}{{end}}
{{end}}{{else}}{{/* services registered locally - duplication here prevents duplication in the final config */}}
## standard backend {{.Name}}
backend app_{{.Name}}
    mode http
{{- if in .Tags "proxy-rewrite-net-cookie"}}{{with $rewriteCookie := key "lb/haproxy/misc/rewriteNetCookie" -}}
{{if ne $rewriteCookie ""}}
{{$rewriteCookie}}
{{- end}}{{end}}{{end -}}
{{if in .Tags "proxy-internal"}}{{with $enaInternal := key "lb/haproxy/misc/enaInternal" -}}
{{if ne $enaInternal ""}}
{{$enaInternal}}
{{- end }}{{end}}{{end -}}
{{if in .Tags "proxy-nostrip" -}}
{{/* do nothing */}}{{else}}
    reqrep ^(GET|PUT|POST|DELETE|PATCH|OPTIONS)\ /{{if in .Tags "proxy-dash2dots"}}{{.Name | replaceAll "-" "."}}{{else}}{{.Name}}{{end}}/(.*) \1\ /\2
{{- end}}
    balance roundrobin{{$svcName := .Name -}}
{{range $dcIdx2, $dcName2 := datacenters -}}
{{$svcNameLoc2 := printf "%s@%s" $svcName $dcName2 -}}
{{if service $svcNameLoc2 -}}
{{range service $svcNameLoc2}}
    server {{.ID}}:{{$dcName2}} {{.Address}}:{{.Port}}{{if in .Tags "proxy-check"}} check{{end}}{{if in .Tags "proxy-ssl"}} ssl verify none{{end}}{{if ne $myDc $dcName2}} backup{{end}}
{{- end}}{{end}}{{end}}
{{end}}{{end}}{{end}}{{end}}{{end}}