feat: Add command to print version

Restore Makefile and update .goreleaser.yaml

Restored Makefile to previous version and then updated
.goreleaser.yaml to use the ldflag with the tag and short hash.

Also ran make docgen to update documentation.

Actually run make docgen this time

.goreleaser.yaml

@@ -4,6 +4,7 @@ builds:
       - "-s -w"
       - "-extldflags=-zrelro"
       - "-extldflags=-znow"
+      - "-extldflags -w -X 'github.com/testifysec/witness/cmd/witness/cmd.Version={{.Tag}}-{{.ShortCommit}}'"
     env:
       - "CGO_ENABLED=0"
       - "GO111MODULE=on"

cmd/witness/cmd/root.go

@@ -54,6 +54,7 @@ func New() *cobra.Command {
 	cmd.AddCommand(VerifyCmd())
 	cmd.AddCommand(RunCmd())
 	cmd.AddCommand(CompletionCmd())
+	cmd.AddCommand(versionCmd())
 	cobra.OnInitialize(func() { preRoot(cmd, ro) })
 	return cmd
 }

cmd/witness/cmd/version.go

@@ -0,0 +1,38 @@
+// Copyright 2022 The Witness Contributors
+//
+// 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 cmd
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+)
+
+var Version = "dev"
+
+// versionCmd represents the version command
+func versionCmd() *cobra.Command {
+	return &cobra.Command{
+		Use:               "version",
+		Short:             "Prints out the witness version",
+		Long:              `Prints out the witness version`,
+		SilenceErrors:     true,
+		SilenceUsage:      true,
+		DisableAutoGenTag: true,
+		Run: func(cmd *cobra.Command, args []string) {
+			fmt.Printf("witness %s\n", Version)
+		},
+	}
+}

docs/witness.md

@@ -16,4 +16,5 @@ Collect and verify attestations about your build environments
 * [witness run](witness_run.md)	 - Runs the provided command and records attestations about the execution
 * [witness sign](witness_sign.md)	 - Signs a file
 * [witness verify](witness_verify.md)	 - Verifies a witness policy
+* [witness version](witness_version.md)	 - Prints out the witness version
 

docs/witness_version.md

@@ -0,0 +1,29 @@
+## witness version
+
+Prints out the witness version
+
+### Synopsis
+
+Prints out the witness version
+
+```
+witness version [flags]
+```
+
+### Options
+
+```
+  -h, --help   help for version
+```
+
+### Options inherited from parent commands
+
+```
+  -c, --config string      Path to the witness config file (default ".witness.yaml")
+  -l, --log-level string   Level of logging to output (debug, info, warn, error) (default "info")
+```
+
+### SEE ALSO
+
+* [witness](witness.md)	 - Collect and verify attestations about your build environments
+