Add kopia policy show command and output parser (#2440)

* Add kopia policy show command and output parser

* Add/fix comments

* Remove redundant check import

---------

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
Co-authored-by: Pavan Navarathna <6504783+pavannd1@users.noreply.github.com>

pkg/kopia/command/const.go

@@ -28,6 +28,7 @@ const (
 	restoreSubCommand     = "restore"
 	runSubCommand         = "run"
 	setSubCommand         = "set"
+	showSubCommand        = "show"
 	snapshotSubCommand    = "snapshot"
 	statsSubCommand       = "stats"
 

pkg/kopia/command/parse_command_output.go

@@ -25,6 +25,7 @@ import (
 	"github.com/dustin/go-humanize"
 	"github.com/kopia/kopia/repo/manifest"
 	"github.com/kopia/kopia/snapshot"
+	"github.com/kopia/kopia/snapshot/policy"
 	"github.com/pkg/errors"
 
 	"github.com/kanisterio/kanister/pkg/field"
@@ -415,3 +416,14 @@ func ErrorsFromOutput(output string) []error {
 
 	return err
 }
+
+// ParsePolicyShow parses the output of a kopia policy show command.
+func ParsePolicyShow(output string) (policy.Policy, error) {
+	policy := policy.Policy{}
+
+	if err := json.Unmarshal([]byte(output), &policy); err != nil {
+		return policy, errors.Wrap(err, "Failed to unmarshal snapshot manifest list")
+	}
+
+	return policy, nil
+}

pkg/kopia/command/parse_command_output_test.go

@@ -19,6 +19,7 @@ import (
 
 	"github.com/kopia/kopia/fs"
 	"github.com/kopia/kopia/snapshot"
+	"github.com/kopia/kopia/snapshot/policy"
 	. "gopkg.in/check.v1"
 )
 
@@ -658,6 +659,48 @@ func (kParse *KopiaParseUtilsTestSuite) TestErrorsFromOutput(c *C) {
 	}
 }
 
+func (kParse *KopiaParseUtilsTestSuite) TestParsePolicyShow(c *C) {
+	for _, tc := range []struct {
+		description   string
+		outputGenFunc func(*C, policy.Policy) string
+		expPolicyShow policy.Policy
+		errChecker    Checker
+	}{
+		{
+			description:   "empty policy show",
+			outputGenFunc: marshalPolicy,
+			expPolicyShow: policy.Policy{},
+			errChecker:    IsNil,
+		},
+		{
+			description:   "default policy show",
+			outputGenFunc: marshalPolicy,
+			expPolicyShow: *policy.DefaultPolicy,
+			errChecker:    IsNil,
+		},
+		{
+			description: "error: parse empty output",
+			outputGenFunc: func(*C, policy.Policy) string {
+				return ""
+			},
+			errChecker: NotNil,
+		},
+		{
+			description: "error: unmarshal fails",
+			outputGenFunc: func(*C, policy.Policy) string {
+				return "asdf"
+			},
+			errChecker: NotNil,
+		},
+	} {
+		outputToParse := tc.outputGenFunc(c, tc.expPolicyShow)
+		gotPolicy, err := ParsePolicyShow(outputToParse)
+		c.Check(err, tc.errChecker, Commentf("Failed for output: %q", outputToParse))
+		c.Log(err)
+		c.Check(gotPolicy, DeepEquals, tc.expPolicyShow)
+	}
+}
+
 func marshalManifestList(c *C, manifestList []*snapshot.Manifest) string {
 	c.Assert(manifestList, NotNil)
 
@@ -666,3 +709,10 @@ func marshalManifestList(c *C, manifestList []*snapshot.Manifest) string {
 
 	return string(b)
 }
+
+func marshalPolicy(c *C, policy policy.Policy) string {
+	b, err := json.Marshal(policy)
+	c.Assert(err, IsNil)
+
+	return string(b)
+}

pkg/kopia/command/policy_show_global.go

@@ -0,0 +1,31 @@
+// Copyright 2023 The Kanister 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.
+
+package command
+
+type PolicyShowGlobalCommandArgs struct {
+	*CommandArgs
+	GetJsonOutput bool
+}
+
+// PolicyShowGlobal returns the kopia command for showing the global policy.
+func PolicyShowGlobal(cmdArgs PolicyShowGlobalCommandArgs) []string {
+	args := commonArgs(cmdArgs.CommandArgs)
+	args = args.AppendLoggable(policySubCommand, showSubCommand, globalFlag)
+	if cmdArgs.GetJsonOutput {
+		args = args.AppendLoggable(jsonFlag)
+	}
+
+	return stringSliceCommand(args)
+}

pkg/kopia/command/policy_set_global_test.go → pkg/kopia/command/policy_test.go

@@ -24,7 +24,7 @@ type KopiaPolicyTestSuite struct{}
 
 var _ = Suite(&KopiaPolicyTestSuite{})
 
-func (kPolicy *KopiaPolicyTestSuite) TestPolicyCommands(c *C) {
+func (kPolicy *KopiaPolicyTestSuite) TestPolicySetCommands(c *C) {
 	for _, tc := range []struct {
 		f           func() []string
 		expectedLog string
@@ -48,3 +48,28 @@ func (kPolicy *KopiaPolicyTestSuite) TestPolicyCommands(c *C) {
 		c.Check(cmd, Equals, tc.expectedLog)
 	}
 }
+
+func (kPolicy *KopiaPolicyTestSuite) TestPolicyShowCommands(c *C) {
+	for _, tc := range []struct {
+		f           func() []string
+		expectedLog string
+	}{
+		{
+			f: func() []string {
+				args := PolicyShowGlobalCommandArgs{
+					CommandArgs: &CommandArgs{
+						RepoPassword:   "encr-key",
+						ConfigFilePath: "path/kopia.config",
+						LogDirectory:   "cache/log",
+					},
+					GetJsonOutput: true,
+				}
+				return PolicyShowGlobal(args)
+			},
+			expectedLog: "kopia --log-level=error --config-file=path/kopia.config --log-dir=cache/log --password=encr-key policy show --global --json",
+		},
+	} {
+		cmd := strings.Join(tc.f(), " ")
+		c.Check(cmd, Equals, tc.expectedLog)
+	}
+}