cmd+doc: add new dropchannelgraph command

Author: guggero

README.md

@@ -288,6 +288,7 @@ Quick access:
 + [chanbackup](doc/chantools_chanbackup.md)
 + [compactdb](doc/chantools_compactdb.md)
 + [derivekey](doc/chantools_derivekey.md)
++ [dropchannelgraph](chantools_dropchannelgraph.md)
 + [dumpbackup](doc/chantools_dumpbackup.md)
 + [dumpchannels](doc/chantools_dumpchannels.md)
 + [filterbackup](doc/chantools_filterbackup.md)

cmd/chantools/dropchannelgraph.go

@@ -0,0 +1,72 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/guggero/chantools/lnd"
+	"github.com/spf13/cobra"
+)
+
+var (
+	nodeBucket      = []byte("graph-node")
+	edgeBucket      = []byte("graph-edge")
+	graphMetaBucket = []byte("graph-meta")
+)
+
+type dropChannelGraphCommand struct {
+	ChannelDB string
+
+	cmd *cobra.Command
+}
+
+func newDropChannelGraphCommand() *cobra.Command {
+	cc := &dropChannelGraphCommand{}
+	cc.cmd = &cobra.Command{
+		Use:   "dropchannelgraph",
+		Short: "Remove all graph related data from a channel DB",
+		Long: `This command removes all graph data from a channel DB,
+forcing the lnd node to do a full graph sync.
+
+CAUTION: Running this command will make it impossible to use the channel DB
+with an older version of lnd. Downgrading is not possible and you'll need to
+run lnd v0.12.0-beta or later after using this command!'`,
+		Example: `chantools dropchannelgraph \
+	--channeldb ~/.lnd/data/graph/mainnet/channel.db`,
+		RunE: cc.Execute,
+	}
+	cc.cmd.Flags().StringVar(
+		&cc.ChannelDB, "channeldb", "", "lnd channel.db file to dump "+
+			"channels from",
+	)
+
+	return cc.cmd
+}
+
+func (c *dropChannelGraphCommand) Execute(_ *cobra.Command, _ []string) error {
+	// Check that we have a channel DB.
+	if c.ChannelDB == "" {
+		return fmt.Errorf("channel DB is required")
+	}
+	db, err := lnd.OpenDB(c.ChannelDB, false)
+	if err != nil {
+		return fmt.Errorf("error opening rescue DB: %v", err)
+	}
+	defer func() { _ = db.Close() }()
+
+	rwTx, err := db.BeginReadWriteTx()
+	if err != nil {
+		return err
+	}
+
+	if err := rwTx.DeleteTopLevelBucket(nodeBucket); err != nil {
+		return err
+	}
+	if err := rwTx.DeleteTopLevelBucket(edgeBucket); err != nil {
+		return err
+	}
+	if err := rwTx.DeleteTopLevelBucket(graphMetaBucket); err != nil {
+		return err
+	}
+	
+	return rwTx.Commit()
+}

cmd/chantools/root.go

@@ -26,7 +26,7 @@ import (
 
 const (
 	defaultAPIURL = "https://blockstream.info/api"
-	version       = "0.8.0"
+	version       = "0.8.1"
 	na            = "n/a"
 
 	Commit = ""
@@ -82,6 +82,7 @@ func main() {
 		newChanBackupCommand(),
 		newCompactDBCommand(),
 		newDeriveKeyCommand(),
+		newDropChannelGraphCommand(),
 		newDumpBackupCommand(),
 		newDumpChannelsCommand(),
 		newDocCommand(),

doc/chantools.md

@@ -21,6 +21,7 @@ Complete documentation is available at https://github.com/guggero/chantools/.
 * [chantools chanbackup](chantools_chanbackup.md)	 - Create a channel.backup file from a channel database
 * [chantools compactdb](chantools_compactdb.md)	 - Create a copy of a channel.db file in safe/read-only mode
 * [chantools derivekey](chantools_derivekey.md)	 - Derive a key with a specific derivation path
+* [chantools dropchannelgraph](chantools_dropchannelgraph.md)	 - Remove all graph related data from a channel DB
 * [chantools dumpbackup](chantools_dumpbackup.md)	 - Dump the content of a channel.backup file
 * [chantools dumpchannels](chantools_dumpchannels.md)	 - Dump all channel information from an lnd channel database
 * [chantools filterbackup](chantools_filterbackup.md)	 - Filter an lnd channel.backup file and remove certain channels

doc/chantools_dropchannelgraph.md

@@ -0,0 +1,38 @@
+## chantools dropchannelgraph
+
+Remove all graph related data from a channel DB
+
+### Synopsis
+
+This command removes all graph data from a channel DB,
+forcing the lnd node to do a full graph sync.
+
+```
+chantools dropchannelgraph [flags]
+```
+
+### Examples
+
+```
+chantools dropchannelgraph \
+	--channeldb ~/.lnd/data/graph/mainnet/channel.db
+```
+
+### Options
+
+```
+      --channeldb string   lnd channel.db file to dump channels from
+  -h, --help               help for dropchannelgraph
+```
+
+### Options inherited from parent commands
+
+```
+  -r, --regtest   Indicates if regtest parameters should be used
+  -t, --testnet   Indicates if testnet parameters should be used
+```
+
+### SEE ALSO
+
+* [chantools](chantools.md)	 - Chantools helps recover funds from lightning channels
+