filter option added to network ls command.

filter option helps to filter output based on name or supported plugins
by CNI networks.

Signed-off-by: Kunal Kushwaha <kunal.kushwaha@gmail.com>

4 files changed, 66 insertions, 4 deletions

diff --git a/cmd/podman/networks/list.go b/cmd/podman/networks/list.go
index 1c0528e5c..24604c055 100644
--- a/cmd/podman/networks/list.go
+++ b/cmd/podman/networks/list.go
@@ -40,8 +40,9 @@ var (
 func networkListFlags(flags *pflag.FlagSet) {
 	// TODO enable filters based on something
 	//flags.StringSliceVarP(&networklistCommand.Filter, "filter", "f",  []string{}, "Pause all running containers")
-	flags.StringVarP(&networkListOptions.Format, "format", "f", "", "Pretty-print containers to JSON or using a Go template")
+	flags.StringVarP(&networkListOptions.Format, "format", "f", "", "Pretty-print networks to JSON or using a Go template")
 	flags.BoolVarP(&networkListOptions.Quiet, "quiet", "q", false, "display only names")
+	flags.StringVarP(&networkListOptions.Filter, "filter", "", "", "Provide filter values (e.g. 'name=podman')")
 }
 
 func init() {
@@ -59,6 +60,14 @@ func networkList(cmd *cobra.Command, args []string) error {
 		nlprs []NetworkListPrintReports
 	)
 
+	// validate the filter pattern.
+	if len(networkListOptions.Filter) > 0 {
+		tokens := strings.Split(networkListOptions.Filter, "=")
+		if len(tokens) != 2 {
+			return fmt.Errorf("invalid filter syntax : %s", networkListOptions.Filter)
+		}
+	}
+
 	responses, err := registry.ContainerEngine().NetworkList(registry.Context(), networkListOptions)
 	if err != nil {
 		return err
@@ -69,7 +78,7 @@ func networkList(cmd *cobra.Command, args []string) error {
 		return quietOut(responses)
 	}
 
-	if networkListOptions.Format == "json" {
+	if strings.ToLower(networkListOptions.Format) == "json" {
 		return jsonOut(responses)
 	}
 
diff --git a/docs/source/markdown/podman-network-ls.1.md b/docs/source/markdown/podman-network-ls.1.md
index 46e424593..7b20cf5e0 100644
--- a/docs/source/markdown/podman-network-ls.1.md
+++ b/docs/source/markdown/podman-network-ls.1.md
@@ -12,7 +12,15 @@ Displays a list of existing podman networks. This command is not available for r
 ## OPTIONS
 **--quiet**, **-q**
 
-The `quiet` option will restrict the output to only the network names
+The `quiet` option will restrict the output to only the network names.
+
+**--format**, **-f**
+
+Pretty-print networks to JSON or using a Go template.
+
+**--filter**
+
+Provide filter values (e.g. 'name=podman').
 
 ## EXAMPLE
 
@@ -36,6 +44,14 @@ outside
 podman9
 ```
 
+Display name of network which support bridge plugin
+```
+# podman network ls --filter plugin=portmap --format {{.Name}}
+podman
+podman2
+podman9
+```
+
 ## SEE ALSO
 podman(1), podman-network(1), podman-network-inspect(1)
 
diff --git a/pkg/domain/entities/network.go b/pkg/domain/entities/network.go
index d001553e0..9beeeb042 100644
--- a/pkg/domain/entities/network.go
+++ b/pkg/domain/entities/network.go
@@ -10,6 +10,7 @@ import (
 type NetworkListOptions struct {
 	Format string
 	Quiet  bool
+	Filter string
 }
 
 // NetworkListReport describes the results from listing networks
@@ -19,6 +20,7 @@ type NetworkListReport struct {
 
 // NetworkInspectOptions describes options for inspect networks
 type NetworkInspectOptions struct {
+	Format string
 }
 
 // NetworkInspectReport describes the results from inspect networks
diff --git a/pkg/domain/infra/abi/network.go b/pkg/domain/infra/abi/network.go
index 5c39b5374..51805a36c 100644
--- a/pkg/domain/infra/abi/network.go
+++ b/pkg/domain/infra/abi/network.go
@@ -6,7 +6,9 @@ import (
 	"fmt"
 	"io/ioutil"
 	"path/filepath"
+	"strings"
 
+	"github.com/containernetworking/cni/libcni"
 	cniversion "github.com/containernetworking/cni/pkg/version"
 	"github.com/containers/libpod/libpod"
 	"github.com/containers/libpod/pkg/domain/entities"
@@ -39,8 +41,19 @@ func (ic *ContainerEngine) NetworkList(ctx context.Context, options entities.Net
 		return nil, err
 	}
 
+	var tokens []string
+	// tokenize the networkListOptions.Filter in key=value.
+	if len(options.Filter) > 0 {
+		tokens = strings.Split(options.Filter, "=")
+		if len(tokens) != 2 {
+			return nil, fmt.Errorf("invalid filter syntax : %s", options.Filter)
+		}
+	}
+
 	for _, n := range networks {
-		reports = append(reports, &entities.NetworkListReport{NetworkConfigList: n})
+		if ifPassesFilterTest(n, tokens) {
+			reports = append(reports, &entities.NetworkListReport{NetworkConfigList: n})
+		}
 	}
 	return reports, nil
 }
@@ -256,3 +269,25 @@ func createMacVLAN(r *libpod.Runtime, name string, options entities.NetworkCreat
 	err = ioutil.WriteFile(cniPathName, b, 0644)
 	return cniPathName, err
 }
+
+func ifPassesFilterTest(netconf *libcni.NetworkConfigList, filter []string) bool {
+	result := false
+	if len(filter) == 0 {
+		// No filter, so pass
+		return true
+	}
+	switch strings.ToLower(filter[0]) {
+	case "name":
+		if filter[1] == netconf.Name {
+			result = true
+		}
+	case "plugin":
+		plugins := network.GetCNIPlugins(netconf)
+		if strings.Contains(plugins, filter[1]) {
+			result = true
+		}
+	default:
+		result = false
+	}
+	return result
+}