Merge "Add deep merge utility to helm-toolkit"

helm-toolkit/templates/utils/_merge.tpl

@@ -0,0 +1,100 @@
+{{/*
+Copyright 2018 The Openstack-Helm Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/}}
+
+{{/*
+Takes a tuple of values and merges into the first (target) one each subsequent
+(source) one in order. If all values to merge are maps, then the tuple can be
+passed as is and the target will be the result, otherwise pass a map with a
+"values" key containing the tuple of values to merge, and the merge result will
+be assigned to the "result" key of the passed map.
+
+When merging maps, for each key in the source, if the target does not define
+that key, the source value is assigned. If both define the key, then the key
+values are merged using this algorithm (recursively) and the result is assigned
+to the target key. Slices are merged by appending them and removing any
+duplicates. Any other values are merged by simply keeping the source, and
+throwing away the target.
+*/}}
+{{- define "helm-toolkit.utils.merge" -}}
+  {{- $local := dict -}}
+  {{- if kindIs "map" $ -}}
+    {{- $_ := set $local "values" $.values -}}
+  {{- else -}}
+    {{- $_ := set $local "values" $ -}}
+  {{- end -}}
+
+  {{- $target := first $local.values -}}
+  {{- range $item := rest $local.values -}}
+    {{- $call := dict "target" $target "source" . -}}
+    {{- $_ := include "helm-toolkit.utils._merge" $call -}}
+    {{- $_ := set $local "result" $call.result -}}
+  {{- end -}}
+
+  {{- if kindIs "map" $ -}}
+    {{- $_ := set $ "result" $local.result -}}
+  {{- end -}}
+{{- end -}}
+
+{{- define "helm-toolkit.utils._merge" -}}
+  {{- $local := dict -}}
+
+  {{- $_ := set $ "result" $.source -}}
+
+  {{/*
+  TODO: Should we `fail` when trying to merge a collection (map or slice) with
+  either a different kind of collection or a scalar?
+  */}}
+
+  {{- if and (kindIs "map" $.target) (kindIs "map" $.source) -}}
+    {{- range $key, $sourceValue := $.source -}}
+      {{- if not (hasKey $.target $key) -}}
+        {{- $_ := set $local "newTargetValue" $sourceValue -}}
+        {{- if kindIs "map" $sourceValue -}}
+          {{- $copy := dict -}}
+          {{- $call := dict "target" $copy "source" $sourceValue -}}
+          {{- $_ := include "helm-toolkit.utils._merge.shallow" $call -}}
+          {{- $_ := set $local "newTargetValue" $copy -}}
+        {{- end -}}
+      {{- else -}}
+        {{- $targetValue := index $.target $key -}}
+        {{- $call := dict "target" $targetValue "source" $sourceValue -}}
+        {{- $_ := include "helm-toolkit.utils._merge" $call -}}
+        {{- $_ := set $local "newTargetValue" $call.result -}}
+      {{- end -}}
+      {{- $_ := set $.target $key $local.newTargetValue -}}
+    {{- end -}}
+    {{- $_ := set $ "result" $.target -}}
+  {{- else if and (kindIs "slice" $.target) (kindIs "slice" $.source) -}}
+    {{- $call := dict "target" $.target "source" $.source -}}
+    {{- $_ := include "helm-toolkit.utils._merge.append_slice" $call -}}
+    {{- $_ := set $ "result" (uniq $call.result) -}}
+  {{- end -}}
+{{- end -}}
+
+{{- define "helm-toolkit.utils._merge.shallow" -}}
+  {{- range $key, $value := $.source -}}
+    {{- $_ := set $.target $key $value -}}
+  {{- end -}}
+{{- end -}}
+
+{{- define "helm-toolkit.utils._merge.append_slice" -}}
+  {{- $local := dict -}}
+  {{- $_ := set $local "result" $.target -}}
+  {{- range $value := $.source -}}
+    {{- $_ := set $local "result" (append $local.result $value) -}}
+  {{- end -}}
+  {{- $_ := set $ "result" $local.result -}}
+{{- end -}}