storage tools cat command to easily cat sentinels and other jsons

cmd/common/st/cat_object.go

@@ -0,0 +1,39 @@
+package st
+
+import (
+	"github.com/spf13/cobra"
+	"github.com/wal-g/tracelog"
+	"github.com/wal-g/wal-g/internal"
+	"github.com/wal-g/wal-g/internal/storagetools"
+)
+
+const (
+	catObjectShortDescription = "Cat the specified storage object to STDOUT"
+
+	decryptFlag    = "decrypt"
+	decompressFlag = "decompress"
+)
+
+// catObjectCmd represents the catObject command
+var catObjectCmd = &cobra.Command{
+	Use:   "cat relative_object_path",
+	Short: catObjectShortDescription,
+	Args:  cobra.ExactArgs(1),
+	Run: func(cmd *cobra.Command, args []string) {
+		objectPath := args[0]
+
+		folder, err := internal.ConfigureFolder()
+		tracelog.ErrorLogger.FatalOnError(err)
+
+		storagetools.HandleCatObject(objectPath, folder, decrypt, decompress)
+	},
+}
+
+var decrypt bool
+var decompress bool
+
+func init() {
+	StorageToolsCmd.AddCommand(catObjectCmd)
+	getObjectCmd.Flags().BoolVar(&decrypt, decryptFlag, false, "decrypt the object")
+	getObjectCmd.Flags().BoolVar(&decompress, decompressFlag, false, "decompress the object")
+}

docs/README.md

@@ -185,6 +185,19 @@ Examples:
 
 ``wal-g st get path/to/remote_file path/to/local_file --no-decrypt`` download the file from storage without decryption.
 
+### ``cat``
+Show the specified storage object to STDOUT. 
+By default, the command will NOT try to decompress and decrypt it.
+Useful for getting sentinels and other meta-information files.
+
+Flags:
+1. Add `--decompress` to decompress source file
+2. Add `--decrypt` to decrypt source file
+
+Examples:
+
+``wal-g st cat path/to/remote_file.json`` show `remote_file.json`
+
 ### ``rm``
 Remove the specified storage object.
 

internal/storagetools/cat_object_handler.go

@@ -0,0 +1,14 @@
+package storagetools
+
+import (
+	"os"
+
+	"github.com/wal-g/tracelog"
+	"github.com/wal-g/wal-g/pkg/storages/storage"
+)
+
+func HandleCatObject(objectPath string, folder storage.Folder, decrypt, decompress bool) {
+	dstFile := os.Stdout
+	err := downloadObject(objectPath, folder, dstFile, decrypt, decompress)
+	tracelog.ErrorLogger.FatalfOnError("Failed to download the file: %v", err)
+}