fees: add dumpfeedb tool

The new dumpfeedb tool dumps the contents of the internal state of a fee
estimator for external validation.

fees/cmd/dumpfeedb/dumpfeedb.go

@@ -0,0 +1,38 @@
+// Copyright (c) 2018 The Decred developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+// Tool dumpfeedb can be used to dump the internal state of the buckets of an
+// estimator's feedb so that it can be externally analyzed.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"path"
+
+	"github.com/decred/dcrd/dcrutil"
+	"github.com/decred/dcrd/fees"
+)
+
+func main() {
+	defaultDir := path.Join(dcrutil.AppDataDir("dcrd", false), "data", "mainnet", "feesdb")
+	db := flag.String("db", defaultDir, "Database location")
+	flag.Parse()
+
+	fmt.Fprintf(os.Stderr, "Dumping contents of %s\n", *db)
+
+	cfg := fees.EstimatorConfig{
+		DatabaseFile:         *db,
+		ReplaceBucketsOnLoad: true,
+	}
+	est, err := fees.NewEstimator(&cfg)
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println(est.DumpBuckets())
+
+	fmt.Fprintf(os.Stderr, "Done\n")
+}