go/zodb/zodbtools: Info

Command to print general information about a ZODB database.
Same as `zodb info` in zodbtools/py.

go/zodb/zodbtools/info.go

+// Copyright (C) 2017  Nexedi SA and Contributors.
+//                     Kirill Smelkov <kirr@nexedi.com>
+//
+// This program is free software: you can Use, Study, Modify and Redistribute
+// it under the terms of the GNU General Public License version 3, or (at your
+// option) any later version, as published by the Free Software Foundation.
+//
+// You can also Link and Combine this program with other software covered by
+// the terms of any of the Free Software licenses or any of the Open Source
+// Initiative approved licenses and Convey the resulting work. Corresponding
+// source of such a combination shall include the source code for all other
+// software used.
+//
+// This program is distributed WITHOUT ANY WARRANTY; without even the implied
+// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+//
+// See COPYING file for full licensing terms.
+// See https://www.nexedi.com/licensing for rationale and options.
+
+// Zodbinfo - Print general information about a ZODB database
+
+package zodbtools
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+
+	"lab.nexedi.com/kirr/go123/prog"
+	"lab.nexedi.com/kirr/neo/go/zodb"
+)
+
+// paramFunc is a function to retrieve 1 storage parameter
+type paramFunc func(ctx context.Context, stor zodb.IStorage) (string, error)
+
+var infov = []struct {name string; getParam paramFunc} {
+	{"name", func(ctx context.Context, stor zodb.IStorage) (string, error) {
+		return stor.URL(), nil
+	}},
+// TODO reenable size
+//	{"size", func(stor zodb.IStorage) (string, error) { return stor.StorageSize(), nil }},
+	{"last_tid", func(ctx context.Context, stor zodb.IStorage) (string, error) {
+		tid, err := stor.LastTid(ctx)
+		return tid.String(), err
+	}},
+}
+
+// {} parameter_name -> get_parameter(stor)
+var infoDict = map[string]paramFunc{}
+
+func init() {
+	for _, info := range infov {
+		infoDict[info.name] = info.getParam
+	}
+}
+
+// Info prints general information about a ZODB storage
+func Info(ctx context.Context, w io.Writer, stor zodb.IStorage, parameterv []string) error {
+	wantnames := false
+	if len(parameterv) == 0 {
+		for _, info := range infov {
+			parameterv = append(parameterv, info.name)
+		}
+		wantnames = true
+	}
+
+	for _, parameter := range parameterv {
+		getParam, ok := infoDict[parameter]
+		if !ok {
+			return fmt.Errorf("invalid parameter: %s", parameter)
+		}
+
+		out := ""
+		if wantnames {
+			out += parameter + "="
+		}
+		value, err := getParam(ctx, stor)
+		if err != nil {
+			return fmt.Errorf("getting %s: %v", parameter, err)
+		}
+		out += value
+		fmt.Fprintf(w, "%s\n", out)
+	}
+
+	return nil
+}
+
+// ----------------------------------------
+
+const infoSummary = "print general information about a ZODB database"
+
+func infoUsage(w io.Writer) {
+	fmt.Fprintf(w,
+`Usage: zodb info [OPTIONS] <storage> [parameter ...]
+Print general information about a ZODB database.
+
+<storage> is an URL (see 'zodb help zurl') of a ZODB-storage.
+
+By default info prints information about all storage parameters. If one or
+more parameter names are given as arguments, info prints the value of each
+named parameter on its own line.
+
+Options:
+
+    -h  --help      show this help
+`)
+}
+
+func infoMain(argv []string) {
+	flags := flag.FlagSet{Usage: func() { infoUsage(os.Stderr) }}
+	flags.Init("", flag.ExitOnError)
+	flags.Parse(argv[1:])
+
+	argv = flags.Args()
+	if len(argv) < 1 {
+		flags.Usage()
+		prog.Exit(2)
+	}
+	storUrl := argv[0]
+
+	ctx := context.Background()
+
+	stor, err := zodb.OpenStorage(ctx, storUrl, &zodb.OpenOptions{ReadOnly: true})
+	if err != nil {
+		prog.Fatal(err)
+	}
+	// TODO defer stor.Close()
+
+	err = Info(ctx, os.Stdout, stor, argv[1:])
+	if err != nil {
+		prog.Fatal(err)
+	}
+}

go/zodb/zodbtools/main.go

@@ -25,6 +25,7 @@ import "lab.nexedi.com/kirr/go123/prog"
 // registry of all zodbtools commands
 var commands = prog.CommandRegistry{
 	// NOTE the order commands are listed here is the order how they will appear in help
+	{"info", infoSummary, infoUsage, infoMain},
 	{"dump", dumpSummary, dumpUsage, dumpMain},
 }