add support for filtering by label selectors

README.md

@@ -99,6 +99,7 @@ You can use `--include` or `-i` to control which resources to include in the kfi
 | group, g      | apiVersion         | rbac.authorization.k8s.io |
 | version, v    | apiVersion         | v1                        |
 | namespace, ns | metadata.namespace | kube-system               |
+| labels, l     | metadata.labels    | app=my-app                |
 
 #### Examples
 
@@ -130,6 +131,12 @@ You can use multiple `--include` flags. kfilt will output resources that match a
 kfilt -f ./pkg/decoder/test.yaml -i k=serviceaccount -i k=configmap
 ```
 
+##### Filter with Label Selectors
+
+```
+kfilt -f ./pkg/decoder/test.yaml -i labels=app=test
+```
+
 ### Excluding Resources
 
 The `--exclude` or `-x` flag will allow you to exclude resources. This supports the same key value pairs as the `--include` flag.
@@ -154,14 +161,22 @@ kfilt -f ./pkg/decoder/test.yaml -x name=test
 kfilt -f ./pkg/decoder/test.yaml -x kind=configmap -x k=serviceaccount
 ```
 
+##### Exclude with Label Selectors
+
+```
+kfilt -f ./pkg/decoder/test.yaml -x labels=app=test
+```
+
 ### Shortcuts
 
-Because "kind" and "name" are the most commonly used fields to filter by, kfilt has special flags allowing you to save some typing.
+Because "kind", "name", and "labels" are the most commonly used fields to filter by, kfilt has special flags allowing you to save some typing.
 
 You can include by "kind" by using the `--kind` (or `-k`) flag with just the name of the kind you want to filter by. You can use `--exclude-kind` (or `-K`) for exclusions.
 
 The corresponding flags for "name" queries are `--name` (`-n`) and `--exclude-name` (`-N`).
 
+Finally, you can use label selectors with the `--labels` (`-l`) and `--exclude-labels` (`L`) flags.
+
 #### Include ConfigMaps and Service Accounts
 
 ```
@@ -174,6 +189,12 @@ kfilt -f ./pkg/decoder/test.yaml -k configmap -k serviceaccount
 kfilt -f ./pkg/decoder/test.yaml -N test
 ```
 
+#### Include resources labeled with "app=test"
+
+```
+kfilt -f ./pkg/decoder/test.yaml -l app=test
+```
+
 ---
 
 <sup>1</sup> *note*: kfilt has not been tested extensively on Windows. Please file an issue if you run into any problems.

cmd/root.go

@@ -20,13 +20,15 @@ var (
 )
 
 type root struct {
-	includeKinds []string
-	includeNames []string
-	excludeKinds []string
-	excludeNames []string
-	include      []string
-	exclude      []string
-	filename     string
+	includeKinds         []string
+	includeNames         []string
+	excludeKinds         []string
+	excludeNames         []string
+	includeLabelSelector []string
+	excludeLabelSelector []string
+	include              []string
+	exclude              []string
+	filename             string
 }
 
 func newRootCommand(args []string) *cobra.Command {
@@ -50,6 +52,8 @@ func newRootCommand(args []string) *cobra.Command {
 	rootCmd.Flags().StringSliceVarP(&root.includeNames, "name", "n", []string{}, "Only include resources with name")
 	rootCmd.Flags().StringSliceVarP(&root.excludeKinds, "exclude-kind", "K", []string{}, "Exclude resources of kind")
 	rootCmd.Flags().StringSliceVarP(&root.excludeNames, "exclude-name", "N", []string{}, "Exclude resources with name")
+	rootCmd.Flags().StringSliceVarP(&root.includeLabelSelector, "labels", "l", []string{}, "Only include resources matching the label selector")
+	rootCmd.Flags().StringSliceVarP(&root.excludeLabelSelector, "exclude-labels", "L", []string{}, "Exclude resources matching the label selector")
 	rootCmd.Flags().StringArrayVarP(&root.include, "include", "i", []string{}, "Include resources matching criteria")
 	rootCmd.Flags().StringArrayVarP(&root.exclude, "exclude", "x", []string{}, "Exclude resources matching criteria")
 	rootCmd.Flags().StringVarP(&root.filename, "filename", "f", "", "Read manifests from file or URL")
@@ -87,6 +91,10 @@ func (r *root) run() error {
 		kfilt.AddInclude(filter.Matcher{Name: n})
 	}
 
+	for _, l := range r.includeLabelSelector {
+		kfilt.AddInclude(filter.Matcher{LabelSelector: l})
+	}
+
 	for _, k := range r.excludeKinds {
 		kfilt.AddExclude(filter.Matcher{Kind: k})
 	}
@@ -95,6 +103,10 @@ func (r *root) run() error {
 		kfilt.AddExclude(filter.Matcher{Name: n})
 	}
 
+	for _, l := range r.excludeLabelSelector {
+		kfilt.AddExclude(filter.Matcher{LabelSelector: l})
+	}
+
 	for _, q := range r.include {
 		if q != "" {
 			s, err := filter.NewMatcher(q)
@@ -115,7 +127,10 @@ func (r *root) run() error {
 		}
 	}
 
-	filtered := kfilt.Filter(results)
+	filtered, err := kfilt.Filter(results)
+	if err != nil {
+		return err
+	}
 
 	// print
 	if err := printer.New().Print(filtered); err != nil {

go.mod

@@ -3,15 +3,10 @@ module github.com/ryane/kfilt
 go 1.12
 
 require (
-	github.com/gogo/protobuf v1.2.1 // indirect
-	github.com/google/gofuzz v1.0.0 // indirect
 	github.com/pkg/errors v0.8.1
 	github.com/spf13/cobra v0.0.2
-	github.com/spf13/pflag v1.0.3 // indirect
-	golang.org/x/net v0.0.0-20190620200207-3b0461eec859 // indirect
-	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/yaml.v2 v2.2.2
 	k8s.io/apimachinery v0.0.0-20190313205120-d7deff9243b1
-	k8s.io/klog v0.3.3 // indirect
-	sigs.k8s.io/yaml v1.1.0 // indirect
+	sigs.k8s.io/kustomize/v3 v3.1.0
+	sigs.k8s.io/yaml v1.1.0
 )