cmd/config set: Support for setting fields imperatively from the cli

cmd/config/configcobra/cmds.go

@@ -76,6 +76,8 @@ func NewConfigCommand(name string) *cobra.Command {
 	root.AddCommand(commands.MergeCommand(name))
 	root.AddCommand(commands.CountCommand(name))
 	root.AddCommand(commands.RunFnCommand(name))
+	root.AddCommand(commands.SubCommand(name))
+	root.AddCommand(commands.SubSetCommand(name))
 
 	root.AddCommand(&cobra.Command{
 		Use:   "docs-merge",

cmd/config/docs/commands/sub.md

@@ -0,0 +1,98 @@
+## set
+
+[Alpha] Set values on Resources fields by substituting values.
+
+### Synopsis
+
+Set values on Resources fields by substituting predefined markers for new values.
+
+`set` looks for markers specified on Resource fields and substitute a new user defined
+value for the existing value.
+
+`set` maybe be used to:
+
+- edit configuration programmatically from the cli or scripts
+- create reusable bundles of configuration
+
+  DIR
+
+    A directory containing Resource configuration.
+
+  NAME
+
+    Optional.  The name of the substitution to perform or display.
+
+  VALUE
+
+    Optional.  The new value to substitute into the field.
+
+
+To print the possible substitutions for the Resources in a directory, run `set` on
+a directory -- e.g. `kustomize config set DIR/`.
+
+#### Tips
+
+- A description of the value may be specified with `--description`.
+- An owner for the field's value may be defined with `--owned-by`.
+- Prevent overriding previous substitutions with `--override=false`.
+- Revert previous substitutions with `--revert`.
+- Create substitutions on Kustomization.yaml's, patches, etc
+
+When overriding or reverting previous substitutions, the description and owner are left
+unmodified unless specified with flags.
+
+To create a substitution for a field see: `kustomize help config set create`
+
+### Examples
+
+  Resource YAML: Name substitution
+
+    # dir/resources.yaml
+    ...
+    metadata:
+        name: PREFIX-app1 # {"substitutions":[{"name":"prefix","marker":"PREFIX-"}]}
+    ...
+    ---
+    ...
+    metadata:
+        name: PREFIX-app2 # {"substitutions":[{"name":"prefix","marker":"PREFIX-"}]}
+    ...
+
+  Show substitutions: Show the possible substitutions
+
+    $ config set dir
+    NAME    DESCRIPTION    VALUE     TYPE    COUNT   SUBSTITUTED   OWNER
+    prefix   ''            PREFIX-   string   2       false
+
+  Perform substitution: set a new value, owner and description
+
+    $ config set dir prefix "test-" --description "test environment" --owned-by "dev"
+    performed 2 substitutions
+
+  Show substitutions: Show the new values
+
+    $ config set dir
+    NAME       DESCRIPTION       VALUE    TYPE    COUNT   SUBSTITUTED   OWNER
+    prefix   'test environment'   test-   string   2       true          dev
+
+  New Resource YAML:
+
+    # dir/resources.yaml
+    ...
+    metadata:
+      name: test-app1 # {"substitutions":[{"name":"prefix","marker":"PREFIX-","value":"test-"}],"ownedBy":"dev","description":"test environment"}
+    ...
+    ---
+    ...
+    metadata:
+      name: test-app2 # {"substitutions":[{"name":"prefix","marker":"PREFIX-","value":"test-"}],"ownedBy":"dev","description":"test environment"}
+    ...
+
+  Revert substitution:
+
+    config set dir prefix --revert
+    performed 2 substitutions
+
+    config set dir
+    NAME       DESCRIPTION       VALUE    TYPE    COUNT   SUBSTITUTED   OWNER  
+    prefix   'test environment'   PREFIX-  string   2       false          dev    

cmd/config/docs/commands/subset.md

@@ -0,0 +1,167 @@
+## sub-set-marker
+
+[Alpha] Create a new substitution for a Resource field
+
+### Synopsis
+
+Create a new substitution for a Resource field -- recognized by `kustomize config set`.
+
+  DIR
+
+    A directory containing Resource configuration.
+
+  NAME
+
+    The name of the substitution to create.
+
+  VALUE
+
+    The current value of the field, or a substring of the field.
+
+#### Tips: Picking Good Marker
+
+Substitutions may be defined by directly editing yaml **or** by running `kustomize config set create`
+to create a new substitution.
+
+Given the YAML:
+    
+    # resource.yaml
+    apiVersion: v1
+    kind: Service
+    metadata:
+      ...
+    spec:
+      ...
+      ports:
+        ...
+      - name: http
+        port: 8080
+        ...
+
+Create a new set marker:
+
+    # create a substitution for ports
+    $ kustomize config set create dir/ http-port 8080 --type "int" --field "port"
+
+Modified YAML:
+
+    # resource.yaml
+    apiVersion: v1
+    kind: Service
+    metadata:
+      ...
+    spec:
+      ...
+      ports:
+        ...
+      - name: http
+        port: 8080 # {"substitutions":[{"name":"port","marker":"[MARKER]"}],"type":"int"}
+        ...
+
+Change the value using the `set` command:
+
+    # change the http-port value to 8081
+    $ kustomize config set dir/ http-port 8081
+
+Resources fields with a field name matching `--field` and field value matching `VALUE` will
+have a line comment added marking this field as settable.
+
+Substitution markers may be:
+
+- valid field values (e.g. `8080` for a port)
+  - Note: `008080` would be preferred because it is more recognizable as a marker
+- invalid values that adhere to the schema (e.g. `0000` for a port)
+- values that do not adhere to the schema (e.g. `[PORT]` for port)
+
+Markers **SHOULD be clearly identifiable as a marker and either**:
+
+- **adhere to the field schema** -- e.g. use a valid value
+
+
+    port: 008080 # {"substitutions":[{"name":"port","marker":"008080"}],"type":"int"}
+
+- **be pre-filled in with a value** -- e.g. set the value when setting the marker
+
+
+    port: 8080 # {"substitutions":[{"name":"port","marker":"[MARKER]","value":"8080""}],"type":"int"}
+
+**Note:** The important thing is that in both cases the Resource configuration may be directly
+applied to a cluster and validated by tools without the tool knowing about the substitution
+marker.
+
+The difference between the preceding examples is that:
+
+- the former will be shown as `SUBSTITUTED=false` (`config sub dir/` exits non-0)
+- the latter with show up as `SUBSTITUTED=true` (`config sub dir/` exits 0)
+
+When choosing the which to use, consider that checks for unsubstituted values MAY be
+configured as pre-commit checks -- if you want to these checks to fail if the value
+hasn't been substituted, then don't specify a `value`.
+
+Markers which are invalid field values MAY be chosen in cases where it is preferred to have
+the create or update request fail rather than succeed if the substitution has not yet been
+performed.
+
+A substitution may be a substring of the full field:
+
+    $ kustomize config set create dir/ app-image-tag v1.0.01 --type "string" --field "image"
+
+    image: gcr.io/example/app:v1.0.1 # {"substitutions":[{"name":"app-image-tag","marker":"[MARKER]","value":"v1.0.1"}]}
+
+
+A single field value may have multiple substitutions applied to it:
+
+    name: PREFIX-app-SUFFIX # {"substitutions":[{"name":"prefix","marker":"PREFIX-"},{"name":"suffix","marker":"-SUFFIX"}]}
+
+#### Substitution Format
+
+Substitutions are defined as json encoded FieldMeta comments on fields.
+
+FieldMeta Schema read by `sub`:
+
+    {
+      "title": "FieldMeta",
+      "type": "object",
+      "properties": {
+        "substitutions": {
+          "type": "array",
+          "description": "Possible substitutions that may be performed against this field.",
+          "items": {
+            "type": "object",
+            "properties": {
+              "name": "Name of the substitution.",
+              "marker": "Marker for the value to be substituted.",
+              "value": "Current substituted value"
+            }   
+          }
+        },
+        "type": {
+          "type": "string",
+          "description": "The value type.  Defaults to string."
+          "enum": ["string", "int", "float", "bool"]
+        },
+        "description": {
+          "type": "string",
+          "description": "A description of the field's current value.  Optional."
+        },
+        "ownedBy": {
+          "type": "string",
+          "description": "The current owner of the field.  Optional."
+        },
+      }
+    }
+
+### Examples
+
+    # set a substitution for port fields matching "8080"
+    kustomize config sub create dir/ port 8080 --type "int" --field port \
+         --description "default port used by the app"
+
+    # set a substitution for port fields matching "8080", using "0000" as a marker.
+    kustomize config sub dir/ port 8080 --marker "0000" --type "int" \
+        --field port --description "default port used by the app"
+
+    # substitute a substring of a field rather than the full field -- e.g. only the
+    # image tag, not the full image
+    kustomize config sub dir/ app-image-tag v1.0.1 --type "string" --substring \
+        --field port --description "current stable release"

cmd/config/go.mod

@@ -4,6 +4,7 @@ go 1.13
 
 require (
 	github.com/go-errors/errors v1.0.1
+	github.com/olekukonko/tablewriter v0.0.4
 	github.com/posener/complete/v2 v2.0.1-alpha.12
 	github.com/spf13/cobra v0.0.5
 	github.com/spf13/pflag v1.0.5

cmd/config/go.sum

@@ -61,6 +61,8 @@ github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/magiconair/properties v1.8.0 h1:LLgXmsheXeRoUOBOjtwPQCWIYqM/LU1ayDtDePerRcY=
 github.com/magiconair/properties v1.8.0/go.mod h1:PppfXfuXeibc/6YijjN8zIbojt8czPbwD3XqdrwzmxQ=
 github.com/mailru/easyjson v0.0.0-20160728113105-d5b7844b561a/go.mod h1:C1wdFJiN94OJF2b5HbByQZoLdCWB1Yqtg26g4irojpc=
+github.com/mattn/go-runewidth v0.0.7 h1:Ei8KR0497xHyKJPAv59M1dkC+rOZCMBJ+t3fZ+twI54=
+github.com/mattn/go-runewidth v0.0.7/go.mod h1:H031xJmbD/WCDINGzjvQ9THkh0rPKHF+m2gUSrubnMI=
 github.com/mitchellh/go-homedir v1.1.0 h1:lukF9ziXFxDFPkA1vsr5zpc1XuPDn/wFntq5mG+4E0Y=
 github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/mitchellh/mapstructure v1.1.2 h1:fmNYVwqnSfB9mZU6OS2O6GsXM+wcskZDuKQzvN1EDeE=
@@ -72,6 +74,8 @@ github.com/modern-go/reflect2 v0.0.0-20180701023420-4b7aa43c6742/go.mod h1:bx2lN
 github.com/modern-go/reflect2 v1.0.1/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=
 github.com/munnerz/goautoneg v0.0.0-20120707110453-a547fc61f48d/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
 github.com/mxk/go-flowrate v0.0.0-20140419014527-cca7078d478f/go.mod h1:ZdcZmHo+o7JKHSa8/e818NopupXU1YMK5fe1lsApnBw=
+github.com/olekukonko/tablewriter v0.0.4 h1:vHD/YYe1Wolo78koG299f7V/VAS08c6IpCLn+Ejf/w8=
+github.com/olekukonko/tablewriter v0.0.4/go.mod h1:zq6QwlOf5SlnkVbMSr5EoBv3636FWnp+qbPhuoO21uA=
 github.com/onsi/ginkgo v0.0.0-20170829012221-11459a886d9c/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/ginkgo v1.10.1/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=

cmd/config/internal/commands/cmdsub.go

@@ -0,0 +1,162 @@
+// Copyright 2019 Google LLC
+//
+// 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.
+
+package commands
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/olekukonko/tablewriter"
+	"github.com/spf13/cobra"
+	"sigs.k8s.io/kustomize/cmd/config/internal/generateddocs/commands"
+	"sigs.k8s.io/kustomize/cmd/config/internal/sub"
+	"sigs.k8s.io/kustomize/kyaml/errors"
+	"sigs.k8s.io/kustomize/kyaml/kio"
+)
+
+// NewSubRunner returns a command runner.
+func NewSubRunner(parent string) *SubRunner {
+	r := &SubRunner{}
+	c := &cobra.Command{
+		Use:     "set DIR [NAME] [VALUE]",
+		Args:    cobra.RangeArgs(1, 3),
+		Short:   commands.SubShort,
+		Long:    commands.SubLong,
+		Example: commands.SubExamples,
+		Aliases: []string{"sub"},
+		PreRunE: r.preRunE,
+		RunE:    r.runE,
+	}
+	c.Flags().BoolVar(&r.Perform.Override, "override", true,
+		"override previously substituted values.")
+	c.Flags().BoolVar(&r.Perform.Revert, "revert", false,
+		"override previously substituted values.")
+	fixDocs(parent, c)
+	r.Command = c
+	c.AddCommand(SubSetCommand(parent))
+	return r
+}
+
+func SubCommand(parent string) *cobra.Command {
+	return NewSubRunner(parent).Command
+}
+
+type SubRunner struct {
+	Command *cobra.Command
+	Lookup  sub.LookupSubstitutions
+	Perform sub.PerformSubstitutions
+}
+
+func (r *SubRunner) preRunE(c *cobra.Command, args []string) error {
+	if len(args) > 1 {
+		r.Perform.Name = args[1]
+		r.Lookup.Name = args[1]
+	}
+	if len(args) > 2 {
+		r.Perform.NewValue = args[2]
+	}
+	if len(args) < 2 && r.Perform.Revert {
+		return errors.Errorf("must specify NAME with --revert")
+	}
+
+	var mutex int
+	if r.Perform.Revert {
+		mutex++
+	}
+	if r.Perform.Override {
+		mutex++
+	}
+	if mutex > 1 {
+		return errors.Errorf("--revert, --override are mutually exclusive")
+	}
+
+	return nil
+}
+
+func (r *SubRunner) runE(c *cobra.Command, args []string) error {
+
+	if len(args) == 3 {
+		return handleError(c, r.perform(c, args))
+	}
+	if len(args) == 2 && r.Perform.Revert {
+		return handleError(c, r.perform(c, args))
+	}
+
+	return handleError(c, r.lookup(c, args))
+}
+
+func (r *SubRunner) lookup(c *cobra.Command, args []string) error {
+	// lookup the substitutions
+	err := kio.Pipeline{
+		Inputs:  []kio.Reader{&kio.LocalPackageReader{PackagePath: args[0]}},
+		Filters: []kio.Filter{&r.Lookup},
+	}.Execute()
+	if err != nil {
+		return err
+	}
+
+	remaining := false
+	table := tablewriter.NewWriter(c.OutOrStdout())
+	table.SetRowLine(false)
+	table.SetBorder(false)
+	table.SetHeaderLine(false)
+	table.SetColumnSeparator(" ")
+	table.SetCenterSeparator(" ")
+	table.SetAlignment(tablewriter.ALIGN_LEFT)
+	table.SetHeader([]string{
+		"NAME", "DESCRIPTION", "VALUE", "TYPE", "COUNT", "SUBSTITUTED", "OWNER",
+	})
+	for i := range r.Lookup.SubstitutionCounts {
+		s := r.Lookup.SubstitutionCounts[i]
+		remaining = remaining || s.Count > s.CountComplete
+		v := s.CurrentValue
+		if s.CurrentValue == "" {
+			v = s.Marker
+		}
+		table.Append([]string{
+			s.Name,
+			"'" + s.Description + "'",
+			v,
+			fmt.Sprintf("%v", s.Type),
+			fmt.Sprintf("%d", s.Count),
+			fmt.Sprintf("%v", s.Count == s.CountComplete),
+			s.OwnedBy,
+		})
+	}
+	table.Render()
+
+	if remaining {
+		os.Exit(1)
+	}
+	return nil
+}
+
+// perform the substitutions
+func (r *SubRunner) perform(c *cobra.Command, args []string) error {
+	rw := &kio.LocalPackageReadWriter{
+		PackagePath: args[0],
+	}
+	// perform the substitutions in the package
+	err := kio.Pipeline{
+		Inputs:  []kio.Reader{rw},
+		Filters: []kio.Filter{&r.Perform},
+		Outputs: []kio.Writer{rw},
+	}.Execute()
+	if err != nil {
+		return err
+	}
+	fmt.Fprintf(c.OutOrStdout(), "performed %d substitutions\n", r.Perform.Count)
+	return nil
+}

cmd/config/internal/commands/cmdsubcreate.go

@@ -0,0 +1,93 @@
+// Copyright 2019 Google LLC
+//
+// 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.
+
+package commands
+
+import (
+	"github.com/spf13/cobra"
+	"sigs.k8s.io/kustomize/cmd/config/internal/generateddocs/commands"
+	"sigs.k8s.io/kustomize/cmd/config/internal/sub"
+	"sigs.k8s.io/kustomize/kyaml/kio"
+)
+
+// NewSubSetRunner returns a command runner.
+func NewSubSetRunner(parent string) *SubSetRunner {
+	r := &SubSetRunner{}
+	set := &cobra.Command{
+		Use:     "create PKG_DIR NAME [VALUE]",
+		Args:    cobra.ExactArgs(3),
+		Short:   commands.SubsetShort,
+		Long:    commands.SubsetLong,
+		Example: commands.SubsetExamples,
+		PreRunE: r.preRunE,
+		RunE:    r.runE,
+	}
+	set.Flags().StringVar(&r.Set.Marker.OwnedBy, "owned-by", "",
+		"set this owner on for the current value.")
+	set.Flags().StringVar(&r.Set.Marker.Description, "description", "",
+		"set this description for the current value description.")
+	set.Flags().StringVar(&r.Set.Marker.Substitution.Marker, "marker", "[MARKER]",
+		"use this marker.")
+	set.Flags().StringVar(&r.Set.Marker.Field, "field", "",
+		"name of the field to set -- e.g. --field port")
+	set.Flags().StringVar(&r.Set.ResourceMeta.Name, "name", "",
+		"name of the Resource on which to set the substitution.")
+	set.Flags().StringVar(&r.Set.ResourceMeta.Kind, "kind", "",
+		"kind of the Resource on which to set substitution.")
+	set.Flags().StringVar(&r.Set.Marker.Type, "type", "",
+		"field type -- e.g. int,float,bool,string.")
+	set.Flags().BoolVar(&r.Set.Marker.PartialMatch, "substring", false,
+		"if true, the value may be a substring of the current value.")
+	fixDocs(parent, set)
+	set.MarkFlagRequired("type")
+	set.MarkFlagRequired("field")
+	r.Command = set
+	return r
+}
+
+func SubSetCommand(parent string) *cobra.Command {
+	return NewSubSetRunner(parent).Command
+}
+
+type SubSetRunner struct {
+	Command *cobra.Command
+	Set     sub.SetSubstitutionMarker
+}
+
+func (r *SubSetRunner) runE(c *cobra.Command, args []string) error {
+	return handleError(c, r.set(c, args))
+}
+
+func (r *SubSetRunner) preRunE(c *cobra.Command, args []string) error {
+	r.Set.Marker.Substitution.Name = args[1]
+	r.Set.Marker.Substitution.Value = args[2]
+	return nil
+}
+
+// perform the substitutions
+func (r *SubSetRunner) set(c *cobra.Command, args []string) error {
+	rw := &kio.LocalPackageReadWriter{
+		PackagePath: args[0],
+	}
+	// add the substitution marker to the Resource
+	err := kio.Pipeline{
+		Inputs:  []kio.Reader{rw},
+		Filters: []kio.Filter{&r.Set},
+		Outputs: []kio.Writer{rw},
+	}.Execute()
+	if err != nil {
+		return err
+	}
+	return nil
+}

cmd/config/internal/generateddocs/commands/docs.go

@@ -185,6 +185,263 @@ order they appear in the file).
 var RunFnsExamples = `
 kustomize config run example/`
 
+var SubShort = `[Alpha] Set values on Resources fields by substituting values.`
+var SubLong = `
+Set values on Resources fields by substituting predefined markers for new values.
+
+` + "`" + `set` + "`" + ` looks for markers specified on Resource fields and substitute a new user defined
+value for the existing value.
+
+` + "`" + `set` + "`" + ` maybe be used to:
+
+- edit configuration programmatically from the cli or scripts
+- create reusable bundles of configuration
+
+  DIR
+
+    A directory containing Resource configuration.
+
+  NAME
+
+    Optional.  The name of the substitution to perform or display.
+
+  VALUE
+
+    Optional.  The new value to substitute into the field.
+
+
+To print the possible substitutions for the Resources in a directory, run ` + "`" + `set` + "`" + ` on
+a directory -- e.g. ` + "`" + `kustomize config set DIR/` + "`" + `.
+
+#### Tips
+
+- A description of the value may be specified with ` + "`" + `--description` + "`" + `.
+- An owner for the field's value may be defined with ` + "`" + `--owned-by` + "`" + `.
+- Prevent overriding previous substitutions with ` + "`" + `--override=false` + "`" + `.
+- Revert previous substitutions with ` + "`" + `--revert` + "`" + `.
+- Create substitutions on Kustomization.yaml's, patches, etc
+
+When overriding or reverting previous substitutions, the description and owner are left
+unmodified unless specified with flags.
+
+To create a substitution for a field see: ` + "`" + `kustomize help config set create` + "`" + `
+`
+var SubExamples = `
+  Resource YAML: Name substitution
+
+    # dir/resources.yaml
+    ...
+    metadata:
+        name: PREFIX-app1 # {"substitutions":[{"name":"prefix","marker":"PREFIX-"}]}
+    ...
+    ---
+    ...
+    metadata:
+        name: PREFIX-app2 # {"substitutions":[{"name":"prefix","marker":"PREFIX-"}]}
+    ...
+
+  Show substitutions: Show the possible substitutions
+
+    $ config set dir
+    NAME    DESCRIPTION    VALUE     TYPE    COUNT   SUBSTITUTED   OWNER
+    prefix   ''            PREFIX-   string   2       false
+
+  Perform substitution: set a new value, owner and description
+
+    $ config set dir prefix "test-" --description "test environment" --owned-by "dev"
+    performed 2 substitutions
+
+  Show substitutions: Show the new values
+
+    $ config set dir
+    NAME       DESCRIPTION       VALUE    TYPE    COUNT   SUBSTITUTED   OWNER
+    prefix   'test environment'   test-   string   2       true          dev
+
+  New Resource YAML:
+
+    # dir/resources.yaml
+    ...
+    metadata:
+      name: test-app1 # {"substitutions":[{"name":"prefix","marker":"PREFIX-","value":"test-"}],"ownedBy":"dev","description":"test environment"}
+    ...
+    ---
+    ...
+    metadata:
+      name: test-app2 # {"substitutions":[{"name":"prefix","marker":"PREFIX-","value":"test-"}],"ownedBy":"dev","description":"test environment"}
+    ...
+
+  Revert substitution:
+
+    config set dir prefix --revert
+    performed 2 substitutions
+
+    config set dir
+    NAME       DESCRIPTION       VALUE    TYPE    COUNT   SUBSTITUTED   OWNER  
+    prefix   'test environment'   PREFIX-  string   2       false          dev    `
+
+var SubsetShort = `[Alpha] Create a new substitution for a Resource field`
+var SubsetLong = `
+Create a new substitution for a Resource field -- recognized by ` + "`" + `kustomize config set` + "`" + `.
+
+  DIR
+
+    A directory containing Resource configuration.
+
+  NAME
+
+    The name of the substitution to create.
+
+  VALUE
+
+    The current value of the field, or a substring of the field.
+
+#### Tips: Picking Good Marker
+
+Substitutions may be defined by directly editing yaml **or** by running ` + "`" + `kustomize config set create` + "`" + `
+to create a new substitution.
+
+Given the YAML:
+    
+    # resource.yaml
+    apiVersion: v1
+    kind: Service
+    metadata:
+      ...
+    spec:
+      ...
+      ports:
+        ...
+      - name: http
+        port: 8080
+        ...
+
+Create a new set marker:
+
+    # create a substitution for ports
+    $ kustomize config set create dir/ http-port 8080 --type "int" --field "port"
+
+Modified YAML:
+
+    # resource.yaml
+    apiVersion: v1
+    kind: Service
+    metadata:
+      ...
+    spec:
+      ...
+      ports:
+        ...
+      - name: http
+        port: 8080 # {"substitutions":[{"name":"port","marker":"[MARKER]"}],"type":"int"}
+        ...
+
+Change the value using the ` + "`" + `set` + "`" + ` command:
+
+    # change the http-port value to 8081
+    $ kustomize config set dir/ http-port 8081
+
+Resources fields with a field name matching ` + "`" + `--field` + "`" + ` and field value matching ` + "`" + `VALUE` + "`" + ` will
+have a line comment added marking this field as settable.
+
+Substitution markers may be:
+
+- valid field values (e.g. ` + "`" + `8080` + "`" + ` for a port)
+  - Note: ` + "`" + `008080` + "`" + ` would be preferred because it is more recognizable as a marker
+- invalid values that adhere to the schema (e.g. ` + "`" + `0000` + "`" + ` for a port)
+- values that do not adhere to the schema (e.g. ` + "`" + `[PORT]` + "`" + ` for port)
+
+Markers **SHOULD be clearly identifiable as a marker and either**:
+
+- **adhere to the field schema** -- e.g. use a valid value
+
+
+    port: 008080 # {"substitutions":[{"name":"port","marker":"008080"}],"type":"int"}
+
+- **be pre-filled in with a value** -- e.g. set the value when setting the marker
+
+
+    port: 8080 # {"substitutions":[{"name":"port","marker":"[MARKER]","value":"8080""}],"type":"int"}
+
+**Note:** The important thing is that in both cases the Resource configuration may be directly
+applied to a cluster and validated by tools without the tool knowing about the substitution
+marker.
+
+The difference between the preceding examples is that:
+
+- the former will be shown as ` + "`" + `SUBSTITUTED=false` + "`" + ` (` + "`" + `config sub dir/` + "`" + ` exits non-0)
+- the latter with show up as ` + "`" + `SUBSTITUTED=true` + "`" + ` (` + "`" + `config sub dir/` + "`" + ` exits 0)
+
+When choosing the which to use, consider that checks for unsubstituted values MAY be
+configured as pre-commit checks -- if you want to these checks to fail if the value
+hasn't been substituted, then don't specify a ` + "`" + `value` + "`" + `.
+
+Markers which are invalid field values MAY be chosen in cases where it is preferred to have
+the create or update request fail rather than succeed if the substitution has not yet been
+performed.
+
+A substitution may be a substring of the full field:
+
+    $ kustomize config set create dir/ app-image-tag v1.0.01 --type "string" --field "image"
+
+    image: gcr.io/example/app:v1.0.1 # {"substitutions":[{"name":"app-image-tag","marker":"[MARKER]","value":"v1.0.1"}]}
+
+
+A single field value may have multiple substitutions applied to it:
+
+    name: PREFIX-app-SUFFIX # {"substitutions":[{"name":"prefix","marker":"PREFIX-"},{"name":"suffix","marker":"-SUFFIX"}]}
+
+#### Substitution Format
+
+Substitutions are defined as json encoded FieldMeta comments on fields.
+
+FieldMeta Schema read by ` + "`" + `sub` + "`" + `:
+
+    {
+      "title": "FieldMeta",
+      "type": "object",
+      "properties": {
+        "substitutions": {
+          "type": "array",
+          "description": "Possible substitutions that may be performed against this field.",
+          "items": {
+            "type": "object",
+            "properties": {
+              "name": "Name of the substitution.",
+              "marker": "Marker for the value to be substituted.",
+              "value": "Current substituted value"
+            }   
+          }
+        },
+        "type": {
+          "type": "string",
+          "description": "The value type.  Defaults to string."
+          "enum": ["string", "int", "float", "bool"]
+        },
+        "description": {
+          "type": "string",
+          "description": "A description of the field's current value.  Optional."
+        },
+        "ownedBy": {
+          "type": "string",
+          "description": "The current owner of the field.  Optional."
+        },
+      }
+    }
+`
+var SubsetExamples = `
+    # set a substitution for port fields matching "8080"
+    kustomize config sub create dir/ port 8080 --type "int" --field port \
+         --description "default port used by the app"
+
+    # set a substitution for port fields matching "8080", using "0000" as a marker.
+    kustomize config sub dir/ port 8080 --marker "0000" --type "int" \
+        --field port --description "default port used by the app"
+
+    # substitute a substring of a field rather than the full field -- e.g. only the
+    # image tag, not the full image
+    kustomize config sub dir/ app-image-tag v1.0.1 --type "string" --substring \
+        --field port --description "current stable release"`
+
 var TreeShort = `[Alpha] Display Resource structure from a directory or stdin.`
 var TreeLong = `
 [Alpha] Display Resource structure from a directory or stdin.

cmd/config/internal/sub/addkio.go

@@ -0,0 +1,39 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package sub
+
+import (
+	"sigs.k8s.io/kustomize/kyaml/kio"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+var _ kio.Filter = &SetSubstitutionMarker{}
+
+// Sub performs substitutions
+type SetSubstitutionMarker struct {
+	// Marker is the marker to set
+	Marker Marker
+
+	// ResourceMeta defines the Resource to set the marker on
+	ResourceMeta yaml.ResourceMeta
+}
+
+func (s *SetSubstitutionMarker) Filter(input []*yaml.RNode) ([]*yaml.RNode, error) {
+	for i := range input {
+		m, err := input[i].GetMeta()
+		if err != nil {
+			return nil, err
+		}
+		if s.ResourceMeta.Name != "" && m.Name != s.ResourceMeta.Name {
+			continue
+		}
+		if s.ResourceMeta.Kind != "" && m.Kind != s.ResourceMeta.Kind {
+			continue
+		}
+		if err := input[i].PipeE(&s.Marker); err != nil {
+			return nil, err
+		}
+	}
+	return input, nil
+}

cmd/config/internal/sub/addyaml.go

@@ -0,0 +1,105 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package sub
+
+import (
+	"strings"
+
+	"sigs.k8s.io/kustomize/kyaml/errors"
+	"sigs.k8s.io/kustomize/kyaml/fieldmeta"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+var _ yaml.Filter = &Marker{}
+
+// substituteResource substitutes a Marker value on a field
+type Marker struct {
+	// Path is the path of the field to add the substitution for
+	Field string
+
+	// Substitution is the substitution to add
+	Substitution fieldmeta.Substitution
+
+	// PartialMatch if true will match if the Substitution value is a substring of the current
+	// value.
+	PartialMatch bool
+
+	Description string
+	OwnedBy     string
+	Type        string
+
+	// currentFieldName is the name of the current field being processed
+	currentFieldName string
+}
+
+// Filter performs the substitutions for a single object
+func (m *Marker) Filter(object *yaml.RNode) (*yaml.RNode, error) {
+	switch object.YNode().Kind {
+	case yaml.DocumentNode:
+		return m.Filter(yaml.NewRNode(object.YNode().Content[0]))
+	case yaml.MappingNode:
+		return object, object.VisitFields(func(node *yaml.MapNode) error {
+			// set the current field name
+			n := m.currentFieldName
+			defer func() { m.currentFieldName = n }()
+			m.currentFieldName = node.Key.YNode().Value
+			_, err := m.Filter(node.Value)
+			return err
+		})
+	case yaml.SequenceNode:
+		return object, object.VisitElements(func(node *yaml.RNode) error {
+			_, err := m.Filter(node)
+			return err
+		})
+	case yaml.ScalarNode:
+		if m.currentFieldName != m.Field {
+			return object, nil
+		}
+		if err := m.createSub(object); err != nil {
+			return nil, err
+		}
+		return object, nil
+	default:
+		return object, nil
+	}
+}
+
+func (as *Marker) createSub(field *yaml.RNode) error {
+	// doesn't match the supplied value
+	if field.YNode().Value != as.Substitution.Value {
+		if !as.PartialMatch || !strings.Contains(field.YNode().Value, as.Substitution.Value) {
+			return nil
+		}
+	}
+
+	fm := fieldmeta.FieldMeta{}
+	if err := fm.Read(field); err != nil {
+		return errors.Wrap(err)
+	}
+	fm.OwnedBy = as.OwnedBy
+	fm.Description = as.Description
+	fm.Type = fieldmeta.FieldValueType(as.Type)
+	if as.Substitution.Marker == "" {
+		as.Substitution.Marker = "[MARKER]"
+	}
+
+	found := false
+	for i := range fm.Substitutions {
+		s := fm.Substitutions[i]
+		if s.Name == as.Substitution.Name {
+			// update the substitution if we find it
+			found = true
+			fm.Substitutions[i] = as.Substitution
+			break
+		}
+	}
+	if !found {
+		// add the substitution if it wasn't found
+		fm.Substitutions = append(fm.Substitutions, as.Substitution)
+	}
+	if err := fm.Write(field); err != nil {
+		return errors.Wrap(err)
+	}
+	return nil
+}

cmd/config/internal/sub/dokio.go

@@ -0,0 +1,53 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package sub
+
+import (
+	"sigs.k8s.io/kustomize/kyaml/kio"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+var _ kio.Filter = &PerformSubstitutions{}
+
+// Sub performs substitutions
+type PerformSubstitutions struct {
+	// Name is the name of the substitution to perform
+	Name string
+
+	// NewValue is the substitution value
+	NewValue string
+
+	// Override if set to true will re-substitute already fields with a new value
+	Override bool
+
+	// Revert if set to true will substitute fields back to the marker value
+	Revert bool
+
+	// Description, if set will annotate the field with a description.
+	Description string
+
+	// OwnedBy, if set will annotate the field with an owner.
+	OwnedBy string
+
+	// Count is the number of substitutions performed by Filter.
+	Count int
+}
+
+func (s *PerformSubstitutions) Filter(input []*yaml.RNode) ([]*yaml.RNode, error) {
+	for i := range input {
+		p := &performSubstitutions{
+			Name:        s.Name,
+			Override:    s.Override,
+			Revert:      s.Revert,
+			NewValue:    s.NewValue,
+			OwnedBy:     s.OwnedBy,
+			Description: s.Description,
+		}
+		if err := input[i].PipeE(p); err != nil {
+			return nil, err
+		}
+		s.Count += p.Count
+	}
+	return input, nil
+}

cmd/config/internal/sub/doyaml.go

@@ -0,0 +1,155 @@
+// Copyright 2019 Google LLC
+//
+// 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.
+
+// Package sub substitutes strings in fields
+package sub
+
+import (
+	"strings"
+
+	"sigs.k8s.io/kustomize/kyaml/fieldmeta"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+var _ yaml.Filter = &performSubstitutions{}
+
+// substituteResource substitutes a Marker value on a field
+type performSubstitutions struct {
+	// Name of the substitution to perform.
+	Name string
+
+	// Override if set to true will replace previously substituted values
+	Override bool
+
+	// Revert if set to true will undo previously substituted values
+	Revert bool
+
+	// NewValue is the new value to set.  Mutually exclusive with Revert.
+	NewValue string
+
+	// Description, if set will annotate the field with a description.
+	Description string
+
+	// OwnedBy, if set will annotate the field with an owner.
+	OwnedBy string
+
+	// Count will be incremented for each substituted value.
+	Count int
+}
+
+// Filter performs the substitutions for a single object
+func (fs *performSubstitutions) Filter(object *yaml.RNode) (*yaml.RNode, error) {
+	switch object.YNode().Kind {
+	case yaml.DocumentNode:
+		return fs.Filter(yaml.NewRNode(object.YNode().Content[0]))
+	case yaml.MappingNode:
+		return object, object.VisitFields(func(node *yaml.MapNode) error {
+			_, err := fs.Filter(node.Value)
+			return err
+		})
+	case yaml.SequenceNode:
+		return object, object.VisitElements(func(node *yaml.RNode) error {
+			_, err := fs.Filter(node)
+			return err
+		})
+	case yaml.ScalarNode:
+		s, f, err := fs.findSub(object)
+		if err != nil {
+			return nil, err
+		}
+		if s == nil {
+			return object, nil
+		}
+		return object, fs.substitute(object, s, f)
+	default:
+		return object, nil
+	}
+}
+
+// findSub finds the substitution matching the name if one exists
+func (fs *performSubstitutions) findSub(field *yaml.RNode) (
+	*fieldmeta.Substitution, *fieldmeta.FieldMeta, error) {
+	// check if there are any substitutions for this field
+	var fm = &fieldmeta.FieldMeta{}
+	if err := fm.Read(field); err != nil {
+		return nil, nil, err
+	}
+	if fs.OwnedBy != "" {
+		fm.OwnedBy = fs.OwnedBy
+	}
+	if fs.Description != "" {
+		fm.Description = fs.Description
+	}
+
+	// check if there is a matching substitution
+	for i := range fm.Substitutions {
+		if fm.Substitutions[i].Name == fs.Name {
+			// validate the value if we are not reverting to the marker.
+			// markers are allowed to be invalid.
+			// only validate if there is a substitution matching the name
+			if !fs.Revert {
+				if err := fm.Type.Validate(fs.NewValue); err != nil {
+					return nil, nil, err
+				}
+			}
+			return &fm.Substitutions[i], fm, nil
+		}
+	}
+	return nil, nil, nil
+}
+
+// substitute performs the substitution for the given field, substitution, and metadata
+func (fs *performSubstitutions) substitute(
+	field *yaml.RNode, s *fieldmeta.Substitution, f *fieldmeta.FieldMeta) error {
+	// undo or override previous substitutions by substituting the marker back
+	// NOTE: check if s.Value != "" so we never try to substitute the empty string back
+	if (fs.Revert || fs.Override) && s.Value != "" {
+		// revert to the marker value
+		if strings.Contains(field.YNode().Value, s.Value) {
+			// revert the substitution
+			field.YNode().Value = strings.ReplaceAll(field.YNode().Value, s.Value, s.Marker)
+			// only use the tag matching the type if the marker parses to that type
+			field.YNode().Tag = f.Type.TagForValue(s.Marker)
+			// record that the config has been modified
+		}
+	}
+	if fs.Revert {
+		fs.Count++
+		s.Value = "" // value has been cleared and replaced with marker
+		if err := f.Write(field); err != nil {
+			return err
+		}
+		return nil
+	}
+
+	if s.Value == fs.NewValue || !strings.Contains(field.YNode().Value, s.Marker) {
+		// no substitutions necessary -- already substituted or doesn't have the marker
+		return nil
+	}
+
+	// replace the marker with the new value
+	field.YNode().Value = strings.ReplaceAll(field.YNode().Value, s.Marker, fs.NewValue)
+	// be sure to set the tag so the yaml doesn't incorrectly quote ints, bools or floats
+	field.YNode().Tag = f.Type.Tag()
+	field.YNode().Style = 0
+	// record that the config has been modified
+	fs.Count++
+
+	// update the comment on the field
+	s.Value = fs.NewValue
+	if err := f.Write(field); err != nil {
+		return err
+	}
+	return nil
+}

cmd/config/internal/sub/lookupkio.go

@@ -0,0 +1,69 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package sub
+
+import (
+	"sort"
+
+	"sigs.k8s.io/kustomize/kyaml/kio"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+var _ kio.Filter = &LookupSubstitutions{}
+
+// Sub performs substitutions
+type LookupSubstitutions struct {
+	// Name is the name of the substitution to match.  If unspecified, all substitutions will
+	// be matched.
+	Name string
+
+	// SubstitutionCounts are the aggregate substitutions matched.
+	SubstitutionCounts []FieldSubstitutionCount
+}
+
+type FieldSubstitutionCount struct {
+	// Count is the number of substitutions possible to perform
+	Count int
+
+	// CountComplete is the number of substitutions that have already been performed
+	// independent of this object.
+	CountComplete int
+
+	// FieldSubstitution is the substitution found
+	FieldSubstitution
+}
+
+func (l *LookupSubstitutions) Filter(input []*yaml.RNode) ([]*yaml.RNode, error) {
+	subs := map[string]*FieldSubstitutionCount{}
+	for i := range input {
+		// lookup substitutions for this object
+		ls := &lookupSubstitutions{Name: l.Name}
+		if err := input[i].PipeE(ls); err != nil {
+			return nil, err
+		}
+
+		// aggregate counts for each substitution
+		for j := range ls.Substitutions {
+			sub := ls.Substitutions[j]
+			curr, found := subs[sub.Name]
+			if !found {
+				curr = &FieldSubstitutionCount{FieldSubstitution: sub}
+				subs[sub.Name] = curr
+			}
+			curr.Count++
+			if sub.CurrentValue != "" {
+				curr.CountComplete++
+			}
+		}
+	}
+
+	// pull out and sort the results
+	for _, v := range subs {
+		l.SubstitutionCounts = append(l.SubstitutionCounts, *v)
+	}
+	sort.Slice(l.SubstitutionCounts, func(i, j int) bool {
+		return l.SubstitutionCounts[i].Name < l.SubstitutionCounts[j].Name
+	})
+	return input, nil
+}

cmd/config/internal/sub/lookupyaml.go

@@ -0,0 +1,65 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package sub
+
+import (
+	"sigs.k8s.io/kustomize/kyaml/fieldmeta"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+var _ yaml.Filter = &lookupSubstitutions{}
+
+// substituteResource substitutes a Marker value on a field
+type lookupSubstitutions struct {
+	// Name of the substitution to lookup.  If unspecified lookup all substitutions.
+	Name string
+
+	// FieldSubstitution is the list of substitutions that were found
+	Substitutions []FieldSubstitution
+}
+
+func (ls *lookupSubstitutions) Filter(object *yaml.RNode) (*yaml.RNode, error) {
+	switch object.YNode().Kind {
+	case yaml.DocumentNode:
+		return ls.Filter(yaml.NewRNode(object.YNode().Content[0]))
+	case yaml.MappingNode:
+		return object, object.VisitFields(func(node *yaml.MapNode) error {
+			_, err := ls.Filter(node.Value)
+			return err
+		})
+	case yaml.SequenceNode:
+		return object, object.VisitElements(func(node *yaml.RNode) error {
+			_, err := ls.Filter(node)
+			return err
+		})
+	case yaml.ScalarNode:
+		return object, ls.lookup(object)
+	default:
+		return object, nil
+	}
+}
+
+// lookup finds any substitutions for this field
+func (ls *lookupSubstitutions) lookup(field *yaml.RNode) error {
+	// check if there is a substitution for this field
+	var fm = &fieldmeta.FieldMeta{}
+	if err := fm.Read(field); err != nil {
+		return err
+	}
+
+	for i := range fm.Substitutions {
+		s := fm.Substitutions[i]
+		if ls.Name == "" || ls.Name == s.Name {
+			ls.Substitutions = append(ls.Substitutions, FieldSubstitution{
+				Name:         s.Name,
+				CurrentValue: s.Value,
+				Description:  fm.Description,
+				Marker:       s.Marker,
+				Type:         fm.Type,
+				OwnedBy:      fm.OwnedBy,
+			})
+		}
+	}
+	return nil
+}

cmd/config/internal/sub/types.go

@@ -0,0 +1,29 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package sub
+
+import (
+	"sigs.k8s.io/kustomize/kyaml/fieldmeta"
+)
+
+// FieldSubstitution is a possible field substitution read from a field
+type FieldSubstitution struct {
+	// Name is the name of the substitution
+	Name string
+
+	// Description is a description of the fields current value
+	Description string
+
+	// Value is the current substituted value for the field.
+	CurrentValue string
+
+	// Type is the type of the substitution
+	Type fieldmeta.FieldValueType
+
+	// Marker is the marker used
+	Marker string
+
+	// OwnedBy, if set will annotate the field with an owner.
+	OwnedBy string
+}

kustomize/go.sum

@@ -240,6 +240,8 @@ github.com/mailru/easyjson v0.7.0/go.mod h1:KAzv3t3aY1NaHWoQz1+4F1ccyAH66Jk7yos7
 github.com/matoous/godox v0.0.0-20190911065817-5d6d842e92eb/go.mod h1:1BELzlh859Sh1c6+90blK8lbYy0kwQf1bYlBhBysy1s=
 github.com/mattn/go-colorable v0.1.4/go.mod h1:U0ppj6V5qS13XJ6of8GYAs25YV2eR4EVcfRqFIhoBtE=
 github.com/mattn/go-isatty v0.0.8/go.mod h1:Iq45c/XA43vh69/j3iqttzPXn0bhXyGjM0Hdxcsrc5s=
+github.com/mattn/go-runewidth v0.0.7 h1:Ei8KR0497xHyKJPAv59M1dkC+rOZCMBJ+t3fZ+twI54=
+github.com/mattn/go-runewidth v0.0.7/go.mod h1:H031xJmbD/WCDINGzjvQ9THkh0rPKHF+m2gUSrubnMI=
 github.com/mattn/goveralls v0.0.2/go.mod h1:8d1ZMHsd7fW6IRPKQh46F2WRpyib5/X4FOpevwGNQEw=
 github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=
 github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
@@ -261,6 +263,8 @@ github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRW
 github.com/mxk/go-flowrate v0.0.0-20140419014527-cca7078d478f/go.mod h1:ZdcZmHo+o7JKHSa8/e818NopupXU1YMK5fe1lsApnBw=
 github.com/nbutton23/zxcvbn-go v0.0.0-20180912185939-ae427f1e4c1d/go.mod h1:o96djdrsSGy3AWPyBgZMAGfxZNfgntdJG+11KU4QvbU=
 github.com/oklog/ulid v1.3.1/go.mod h1:CirwcVhetQ6Lv90oh/F+FBtV6XMibvdAFo93nm5qn4U=
+github.com/olekukonko/tablewriter v0.0.4 h1:vHD/YYe1Wolo78koG299f7V/VAS08c6IpCLn+Ejf/w8=
+github.com/olekukonko/tablewriter v0.0.4/go.mod h1:zq6QwlOf5SlnkVbMSr5EoBv3636FWnp+qbPhuoO21uA=
 github.com/onsi/ginkgo v0.0.0-20170829012221-11459a886d9c/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/ginkgo v1.10.1 h1:q/mM8GF/n0shIN8SaAZ0V+jnLPzen6WIVZdiwrRlMlo=

kyaml/fieldmeta/fieldmeta.go

@@ -0,0 +1,134 @@
+package fieldmeta
+
+import (
+	"bytes"
+	"encoding/json"
+	"strconv"
+	"strings"
+
+	"sigs.k8s.io/kustomize/kyaml/errors"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+// FieldMeta contains metadata that may be attached to fields as comments
+type FieldMeta struct {
+	// Substitutions are substitutions that may be performed against this field
+	Substitutions []Substitution `yaml:"substitutions,omitempty" json:"substitutions,omitempty"`
+	// OwnedBy records the owner of this field
+	OwnedBy string `yaml:"ownedBy,omitempty" json:"ownedBy,omitempty"`
+	// DefaultedBy records that this field was default, but may be changed by other owners
+	DefaultedBy string `yaml:"defaultedBy,omitempty" json:"defaultedBy,omitempty"`
+	// Description is a description of the current field value, e.g. why it was set
+	Description string `yaml:"description,omitempty" json:"description,omitempty"`
+	// Type is the type of the field value
+	Type FieldValueType `yaml:"type,omitempty" json:"type,omitempty"`
+}
+
+// Substitution defines a substitution that may be performed against the field
+type Substitution struct {
+	// Name is the name of the substitution and read by tools
+	Name string `yaml:"name,omitempty" json:"name,omitempty"`
+	// Marker is the marker used for replacement
+	Marker string `yaml:"marker,omitempty" json:"marker,omitempty"`
+	// Value is the current value that has been substituted for the Marker
+	Value string `yaml:"value,omitempty" json:"value,omitempty"`
+}
+
+// Read reads the FieldMeta from a node
+func (fm *FieldMeta) Read(n *yaml.RNode) error {
+	if n.YNode().LineComment != "" {
+		v := strings.TrimLeft(n.YNode().LineComment, "#")
+		// if it doesn't Unmarshal that is fine, it means there is no metadata
+		// other comments are valid, they just don't parse
+		d := yaml.NewDecoder(bytes.NewBuffer([]byte(v)))
+		d.KnownFields(false)
+		_ = d.Decode(fm)
+	}
+	return nil
+}
+
+// Write writes the FieldMeta to a node
+func (fm *FieldMeta) Write(n *yaml.RNode) error {
+	b, err := json.Marshal(fm)
+	if err != nil {
+		return err
+	}
+	n.YNode().LineComment = string(b)
+	return nil
+}
+
+// FieldValueType defines the type of input to register
+type FieldValueType string
+
+const (
+	// String defines a string flag
+	String FieldValueType = "string"
+	// Bool defines a bool flag
+	Bool = "bool"
+	// Float defines a float flag
+	Float = "float"
+	// Int defines an int flag
+	Int = "int"
+)
+
+func (it FieldValueType) String() string {
+	if it == "" {
+		return "string"
+	}
+	return string(it)
+}
+
+func (it FieldValueType) Validate(value string) error {
+	switch it {
+	case Int:
+		if _, err := strconv.Atoi(value); err != nil {
+			return errors.WrapPrefixf(err, "value must be an int")
+		}
+	case Bool:
+		if _, err := strconv.ParseBool(value); err != nil {
+			return errors.WrapPrefixf(err, "value must be a bool")
+		}
+	case Float:
+		if _, err := strconv.ParseFloat(value, 64); err != nil {
+			return errors.WrapPrefixf(err, "value must be a float")
+		}
+	}
+	return nil
+}
+
+func (it FieldValueType) Tag() string {
+	switch it {
+	case String:
+		return "!!str"
+	case Bool:
+		return "!!bool"
+	case Int:
+		return "!!int"
+	case Float:
+		return "!!float"
+	}
+	return ""
+}
+
+func (it FieldValueType) TagForValue(value string) string {
+	switch it {
+	case String:
+		return "!!str"
+	case Bool:
+		if _, err := strconv.ParseBool(string(it)); err != nil {
+			return ""
+		}
+		return "!!bool"
+	case Int:
+		if _, err := strconv.ParseInt(string(it), 0, 32); err != nil {
+			return ""
+		}
+		return "!!int"
+	case Float:
+		if _, err := strconv.ParseFloat(string(it), 64); err != nil {
+			return ""
+		}
+		return "!!float"
+	}
+	return ""
+}