add map merge functionality

docs/templating-language.md

@@ -54,6 +54,8 @@ provides the following functions:
   - [in](#in)
   - [loop](#loop)
   - [join](#join)
+  - [mergeMap](#mergemap)
+  - [mergeMapWithOverride](#mergemapwithoverride)
   - [trimSpace](#trimspace)
   - [parseBool](#parsebool)
   - [parseFloat](#parsefloat)
@@ -1223,6 +1225,28 @@ Takes the given list of strings as a pipe and joins them on the provided string:
 {{ $items | join "," }}
 ```
 
+### `mergeMap`
+
+Takes the result from [`explode`](#explode) and an exploded argument then merges it both maps. The argument's source will not be overridden by piped map.
+
+```golang
+{{ $base := tree "base" | explode }}
+{{ $overrides := tree "overrides" | explode | mergeMap $base}}
+{{ with $overrides }}
+{{ .a.b.c }}{{ end }}
+```
+
+### `mergeMapWithOverride`
+
+Takes the result from [`explode`](#explode) and an exploded argument then merges it both maps. The argument's source will be overridden by piped map.
+
+```golang
+{{ $base := tree "base" | explode }}
+{{ $overrides := tree "overrides" | explode | mergeMapWithOverride $base}}
+{{ with $overrides }}
+{{ .a.b.c }}{{ end }}
+```
+
 ### `trimSpace`
 
 Takes the provided input and trims all whitespace, tabs and newlines:

go.mod

@@ -26,8 +26,8 @@ require (
 	github.com/hashicorp/logutils v1.0.0
 	github.com/hashicorp/serf v0.9.4 // indirect
 	github.com/hashicorp/vault/api v1.0.5-0.20190730042357-746c0b111519
+	github.com/imdario/mergo v0.3.12
 	github.com/mattn/go-colorable v0.1.7 // indirect
-	github.com/mattn/go-shellwords v1.0.12
 	github.com/mitchellh/go-homedir v1.1.0
 	github.com/mitchellh/hashstructure v1.0.0
 	github.com/mitchellh/mapstructure v1.3.3

go.sum

@@ -23,8 +23,6 @@ github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDk
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/eikenb/go-shellwords v1.0.12-0.20210603231637-cbc54604f068 h1:y0DBnMgUmMeM+y1h7R2Hv0IZNiAcK5FAjNbRbbJNe3A=
-github.com/eikenb/go-shellwords v1.0.12-0.20210603231637-cbc54604f068/go.mod h1:EZzvwXDESEeg03EKmM+RmDnNOPKG4lLtQsUlTZDWQ8Y=
 github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=
 github.com/fatih/color v1.9.0 h1:8xPHl4/q1VyqGIPif1F+1V3Y3lSmrq01EabUW3CoW5s=
 github.com/fatih/color v1.9.0/go.mod h1:eQcE1qtQxscV5RaZvpXrrb8Drkc3/DdQ+uUYCNjL+zU=
@@ -124,6 +122,8 @@ github.com/hashicorp/vault/sdk v0.1.14-0.20190730042320-0dc007d98cc8 h1:fLUoZ8cI
 github.com/hashicorp/vault/sdk v0.1.14-0.20190730042320-0dc007d98cc8/go.mod h1:B+hVj7TpuQY1Y/GPbCpffmgd+tSEwvhkWnjtSYCaS2M=
 github.com/hashicorp/yamux v0.0.0-20180604194846-3520598351bb/go.mod h1:+NfK9FKeTrX5uv1uIXGdwYDTeHna2qgaIlx54MXqjAM=
 github.com/hashicorp/yamux v0.0.0-20181012175058-2f1d1f20f75d/go.mod h1:+NfK9FKeTrX5uv1uIXGdwYDTeHna2qgaIlx54MXqjAM=
+github.com/imdario/mergo v0.3.12 h1:b6R2BslTbIEToALKP7LxUvijTsNI9TAe80pLWN2g/HU=
+github.com/imdario/mergo v0.3.12/go.mod h1:jmQim1M+e3UYxmgPu/WyfjB3N3VflVyUjjjwH0dnCYA=
 github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
 github.com/json-iterator/go v1.1.9/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
 github.com/julienschmidt/httprouter v1.2.0/go.mod h1:SYymIcj16QtmaHHD7aYtjjsJG7VTCxuUUipMqKk8s4w=
@@ -146,10 +146,6 @@ github.com/mattn/go-isatty v0.0.10/go.mod h1:qgIWMr58cqv1PHHyhnkY9lrL7etaEgOFcME
 github.com/mattn/go-isatty v0.0.11/go.mod h1:PhnuNfih5lzO57/f3n+odYbM4JtupLOxQOAqxQCu2WE=
 github.com/mattn/go-isatty v0.0.12 h1:wuysRhFDzyxgEmMf5xjvJ2M9dZoWAXNNr5LSBS7uHXY=
 github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
-github.com/mattn/go-shellwords v1.0.10 h1:Y7Xqm8piKOO3v10Thp7Z36h4FYFjt5xB//6XvOrs2Gw=
-github.com/mattn/go-shellwords v1.0.10/go.mod h1:EZzvwXDESEeg03EKmM+RmDnNOPKG4lLtQsUlTZDWQ8Y=
-github.com/mattn/go-shellwords v1.0.12 h1:M2zGm7EW6UQJvDeQxo4T51eKPurbeFbe8WtebGE2xrk=
-github.com/mattn/go-shellwords v1.0.12/go.mod h1:EZzvwXDESEeg03EKmM+RmDnNOPKG4lLtQsUlTZDWQ8Y=
 github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=
 github.com/miekg/dns v1.0.14/go.mod h1:W1PPwlIAgtquWBMBEV9nkV9Cazfe8ScdGz/Lj7v3Nrg=
 github.com/miekg/dns v1.1.26 h1:gPxPSwALAeHJSjarOs00QjVdV9QoBvc1D2ujQUr5BzU=
@@ -248,7 +244,6 @@ golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190227155943-e225da77a7e6/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e h1:vcxGaoTs7kV8m5Np9uUNQin4BrLOthgV7252N8V+FwY=
 golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180823144017-11551d06cbcc/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=

template/funcs.go

@@ -26,6 +26,7 @@ import (
 	dep "github.com/hashicorp/consul-template/dependency"
 	"github.com/hashicorp/consul/api"
 	socktmpl "github.com/hashicorp/go-sockaddr/template"
+	"github.com/imdario/mergo"
 	"github.com/pkg/errors"
 	yaml "gopkg.in/yaml.v2"
 )
@@ -739,6 +740,19 @@ func containsSomeFunc(retTrue, invert bool) func([]interface{}, interface{}) (bo
 	}
 }
 
+// mergeMap is used to merge two maps
+func mergeMap(dstMap map[string]interface{}, srcMap map[string]interface{}, args ...func(*mergo.Config)) (map[string]interface{}, error) {
+	if err := mergo.Map(&dstMap, srcMap, args...); err != nil {
+		return nil, err
+	}
+	return dstMap, nil
+}
+
+// mergeMapWithOverride is used to merge two maps with dstMap overriding vaules in srcMap
+func mergeMapWithOverride(dstMap map[string]interface{}, srcMap map[string]interface{}) (map[string]interface{}, error) {
+	return mergeMap(dstMap, srcMap, mergo.WithOverride)
+}
+
 // explode is used to expand a list of keypairs into a deeply-nested hash.
 func explode(pairs []*dep.KeyPair) (map[string]interface{}, error) {
 	m := make(map[string]interface{})

template/template.go

@@ -264,6 +264,8 @@ func funcMap(i *funcMapInput) template.FuncMap {
 		"executeTemplate":       executeTemplateFunc(i.t),
 		"explode":               explode,
 		"explodeMap":            explodeMap,
+		"mergeMap":              mergeMap,
+		"mergeMapWithOverride":  mergeMapWithOverride,
 		"in":                    in,
 		"indent":                indent,
 		"loop":                  loop,

template/template_test.go

@@ -1191,6 +1191,52 @@ func TestTemplate_Execute(t *testing.T) {
 			"bar",
 			false,
 		},
+		{
+			"helper_mergeMap",
+			&NewTemplateInput{
+				Contents: `{{ $base := "{\"voo\":{\"bar\":\"v\"}}" | parseJSON}}{{ $role := tree "list" | explode | mergeMap $base}}{{ range $k, $v := $role }}{{ $k }}{{ $v }}{{ end }}`,
+			},
+			&ExecuteInput{
+				Brain: func() *Brain {
+					b := NewBrain()
+					d, err := dep.NewKVListQuery("list")
+					if err != nil {
+						t.Fatal(err)
+					}
+					b.Remember(d, []*dep.KeyPair{
+						&dep.KeyPair{Key: "", Value: ""},
+						&dep.KeyPair{Key: "foo/bar", Value: "a"},
+						&dep.KeyPair{Key: "zip/zap", Value: "b"},
+					})
+					return b
+				}(),
+			},
+			"foomap[bar:a]voomap[bar:v]zipmap[zap:b]",
+			false,
+		},
+		{
+			"helper_mergeMapWithOverride",
+			&NewTemplateInput{
+				Contents: `{{ $base := "{\"zip\":{\"zap\":\"t\"},\"voo\":{\"bar\":\"v\"}}" | parseJSON}}{{ $role := tree "list" | explode | mergeMapWithOverride $base}}{{ range $k, $v := $role }}{{ $k }}{{ $v }}{{ end }}`,
+			},
+			&ExecuteInput{
+				Brain: func() *Brain {
+					b := NewBrain()
+					d, err := dep.NewKVListQuery("list")
+					if err != nil {
+						t.Fatal(err)
+					}
+					b.Remember(d, []*dep.KeyPair{
+						&dep.KeyPair{Key: "", Value: ""},
+						&dep.KeyPair{Key: "foo/bar", Value: "a"},
+						&dep.KeyPair{Key: "zip/zap", Value: "b"},
+					})
+					return b
+				}(),
+			},
+			"foomap[bar:a]voomap[bar:v]zipmap[zap:b]",
+			false,
+		},
 		{
 			"helper_explode",
 			&NewTemplateInput{