Add import/export to CLI.

This commit adds two new commands:

    bolt import --input INPUT PATH
    bolt export PATH

This exports the database in a simple, nested, key/value JSON document.
Each node in the document has a "key", a "value", and an optional "type".
The key and value fields are both base64 encoded.

1 files changed, 73 insertions, 0 deletions

diff --git a/cmd/bolt/export.go b/cmd/bolt/export.go
new file mode 100644
index 0000000..f3cafc1
--- /dev/null
+++ b/cmd/bolt/export.go
@@ -0,0 +1,73 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+
+	"github.com/boltdb/bolt"
+)
+
+// Export exports the entire database as a JSON document.
+func Export(path string) {
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		fatal(err)
+		return
+	}
+
+	// Open the database.
+	db, err := bolt.Open(path, 0600)
+	if err != nil {
+		fatal(err)
+		return
+	}
+	defer db.Close()
+
+	db.View(func(tx *bolt.Tx) error {
+		// Loop over every bucket and export it as a raw message.
+		var root []*rawMessage
+		for _, b := range tx.Buckets() {
+			message, err := exportBucket(b)
+			if err != nil {
+				fatal(err)
+			}
+			root = append(root, message)
+		}
+
+		// Encode all buckets into JSON.
+		output, err := json.Marshal(root)
+		if err != nil {
+			fatal("encode: ", err)
+		}
+		print(string(output))
+		return nil
+	})
+}
+
+func exportBucket(b *bolt.Bucket) (*rawMessage, error) {
+	// Encode individual key/value pairs into raw messages.
+	var children = make([]*rawMessage, 0)
+	err := b.ForEach(func(k, v []byte) error {
+		var err error
+
+		var child = &rawMessage{Key: k}
+		if child.Value, err = json.Marshal(v); err != nil {
+			return fmt.Errorf("value: %s", err)
+		}
+
+		children = append(children, child)
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	// Encode bucket into a raw message.
+	var root = rawMessage{Type: "bucket"}
+	root.Key = []byte(b.Name())
+	if root.Value, err = json.Marshal(children); err != nil {
+		return nil, fmt.Errorf("children: %s", err)
+	}
+
+	return &root, nil
+}