Add export command to the command line and REPL

tools/vcli/bw/common/common.go

@@ -28,6 +28,7 @@ import (
 	"github.com/google/badwolf/storage"
 	"github.com/google/badwolf/tools/vcli/bw/assert"
 	"github.com/google/badwolf/tools/vcli/bw/command"
+	"github.com/google/badwolf/tools/vcli/bw/export"
 	"github.com/google/badwolf/tools/vcli/bw/load"
 	"github.com/google/badwolf/tools/vcli/bw/repl"
 	"github.com/google/badwolf/tools/vcli/bw/run"
@@ -99,6 +100,7 @@ func InitializeDriver(driverName string, drivers map[string]StoreGenerator) (sto
 func InitializeCommands(driver storage.Store, chanSize, bulkTripleOpSize, builderSize int) []*command.Command {
 	return []*command.Command{
 		assert.New(driver, literal.DefaultBuilder(), chanSize),
+		export.New(driver),
 		load.New(driver, bulkTripleOpSize, builderSize),
 		run.New(driver, chanSize),
 		repl.New(driver, chanSize, bulkTripleOpSize, builderSize),

tools/vcli/bw/export/export.go

@@ -0,0 +1,98 @@
+// Copyright 2016 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package export contains the command allowing to dump all triples of a graphs
+// into a file.
+package export
+
+import (
+	"fmt"
+	"os"
+	"strings"
+	"sync"
+
+	"golang.org/x/net/context"
+
+	"github.com/google/badwolf/storage"
+	"github.com/google/badwolf/tools/vcli/bw/command"
+	"github.com/google/badwolf/triple"
+)
+
+// New creates the help command.
+func New(store storage.Store) *command.Command {
+	cmd := &command.Command{
+		UsageLine: "export <graph_names_separated_by_commas> <file_path>",
+		Short:     "export triples in bulk from graphs into a file.",
+		Long: `Export all the triples in the provided graphs into the provided
+text file.`,
+	}
+	cmd.Run = func(ctx context.Context, args []string) int {
+		return Eval(ctx, cmd.UsageLine+"\n\n"+cmd.Long, args, store)
+	}
+	return cmd
+}
+
+// Eval loads the triples in the file against as indicated by the command.
+func Eval(ctx context.Context, usage string, args []string, store storage.Store) int {
+	if len(args) <= 3 {
+		fmt.Fprintf(os.Stderr, "[ERROR] Missing required file path and/or graph names.\n\n%s", usage)
+		return 2
+	}
+	graphs, path := strings.Split(args[len(args)-2], ","), args[len(args)-1]
+	f, err := os.Create(path)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "[ERROR] Failed to open target file %q with error %v.\n\n", path, err)
+		return 2
+	}
+	defer f.Close()
+	var sgs []storage.Graph
+	for _, gr := range graphs {
+		g, err := store.Graph(ctx, gr)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "[ERROR] Failed to retrieve graph %q with error %v.\n\n", gr, err)
+			return 2
+		}
+		sgs = append(sgs, g)
+	}
+
+	cnt := 0
+	var errs []error
+	var mu sync.Mutex
+	chn := make(chan *triple.Triple, 1000)
+	for _, vg := range sgs {
+		go func(g storage.Graph) {
+			err := g.Triples(ctx, chn)
+			mu.Lock()
+			errs = append(errs, err)
+			mu.Unlock()
+		}(vg)
+	}
+
+	for t := range chn {
+		if _, err := f.WriteString(t.String() + "\n"); err != nil {
+			fmt.Fprintf(os.Stderr, "[ERROR] Failed to write triple %s to file %q, %v.\n\n", t.String(), path, err)
+			return 2
+		}
+		cnt++
+	}
+	for _, err := range errs {
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "[ERROR] Failed to retrieve triples with error %v.\n\n", err)
+			return 2
+		}
+	}
+
+	fmt.Printf("Successfully written %d triples to file %q.\nTriples exported from graphs:\n\t- %s\n", cnt, path, strings.Join(graphs, "\n\t- "))
+	return 0
+}

tools/vcli/bw/repl/repl.go

@@ -32,6 +32,7 @@ import (
 	"github.com/google/badwolf/bql/version"
 	"github.com/google/badwolf/storage"
 	"github.com/google/badwolf/tools/vcli/bw/command"
+	"github.com/google/badwolf/tools/vcli/bw/export"
 	"github.com/google/badwolf/tools/vcli/bw/io"
 	"github.com/google/badwolf/tools/vcli/bw/load"
 )
@@ -94,13 +95,10 @@ func REPL(driver storage.Store, input *os.File, rl readLiner, chanSize, bulkSize
 			fmt.Print(prompt)
 			continue
 		}
-		if strings.HasPrefix(l, "run") {
-			path, cmds, err := runBQLFromFile(ctx, driver, chanSize, l)
-			if err != nil {
-				fmt.Printf("[ERROR] %s\n\n", err)
-			} else {
-				fmt.Printf("Loaded %q and run %d BQL commands successfully\n\n", path, cmds)
-			}
+		if strings.HasPrefix(l, "export") {
+			args := strings.Split("bw "+l, " ")
+			usage := "Wrong syntax\n\n\tload <graph_names_separated_by_commas> <file_path>\n"
+			export.Eval(ctx, usage, args, driver)
 			fmt.Print(prompt)
 			continue
 		}
@@ -111,6 +109,16 @@ func REPL(driver storage.Store, input *os.File, rl readLiner, chanSize, bulkSize
 			fmt.Print(prompt)
 			continue
 		}
+		if strings.HasPrefix(l, "run") {
+			path, cmds, err := runBQLFromFile(ctx, driver, chanSize, l)
+			if err != nil {
+				fmt.Printf("[ERROR] %s\n\n", err)
+			} else {
+				fmt.Printf("Loaded %q and run %d BQL commands successfully\n\n", path, cmds)
+			}
+			fmt.Print(prompt)
+			continue
+		}
 		table, err := runBQL(ctx, l, driver, chanSize)
 		if err != nil {
 			fmt.Printf("[ERROR] %s\n\n", err)