Add loadtest.go script (#2090)

tools/loadtest/loadtest.go

@@ -0,0 +1,152 @@
+// Copyright 2016 Attic Labs, Inc. All rights reserved.
+// Licensed under the Apache License, version 2.0:
+// http://www.apache.org/licenses/LICENSE-2.0
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"math/rand"
+	"os"
+	"os/exec"
+	"strings"
+	"time"
+)
+
+// This script runs random noms commands against random datasets on a database.
+//
+// Example usage:
+// > go run path/to/loadtest.go http://demo.noms.io/cli-tour
+//
+// Imports should be Go builtin libraries only, so that this can be run with "go run".
+
+type runnerFn func(db, ds string)
+
+type runner struct {
+	name string
+	fn   runnerFn
+}
+
+func main() {
+	rand.Seed(time.Now().Unix())
+
+	if len(os.Args) != 2 {
+		fmt.Println("Usage: loadtest <database>")
+		os.Exit(-1)
+	}
+
+	db := os.Args[1]
+
+	rs := []runner{
+		runner{"diff", runDiff},
+		runner{"log diff", runLogDiff},
+		runner{"log show", runLogShow},
+		runner{"show", runShow},
+		runner{"sync", runSync},
+	}
+
+	for ds := range streamDs(db) {
+		start := time.Now()
+		r := rs[rand.Intn(len(rs))]
+		fmt.Println(time.Now().Format(time.Stamp), r.name, db, ds)
+		r.fn(db, fmt.Sprintf("%s::%s", db, ds))
+		fmt.Println("  took", time.Since(start).String())
+	}
+}
+
+func runDiff(db, ds string) {
+	if parent := getParent(db, ds); parent != "" {
+		call(nil, "noms", "diff", ds, parent)
+	} else {
+		fmt.Println("    (no parent, cannot diff)")
+	}
+}
+
+func runLogDiff(db, ds string) {
+	call(nil, "noms", "log", ds)
+}
+
+func runLogShow(db, ds string) {
+	call(nil, "noms", "log", "-show-value", ds)
+}
+
+func runShow(db, ds string) {
+	if strings.HasSuffix(ds, "/raw") {
+		fmt.Println("    (skipping raw file, blobs are too slow)")
+	} else {
+		call(nil, "noms", "show", ds)
+	}
+}
+
+func runSync(db, ds string) {
+	dir, err := ioutil.TempDir("", "loadtest")
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "  ERROR: failed to create temp directory:", err.Error())
+		return
+	}
+
+	defer os.RemoveAll(dir)
+	// Try to sync to parent, then from parent to head.
+	// If there isn't a parent then just sync head.
+	syncDs := fmt.Sprintf("ldb:%s::sync", dir)
+	if parent := getParent(db, ds); parent != "" {
+		call(nil, "noms", "sync", parent, syncDs)
+	}
+	call(nil, "noms", "sync", ds, syncDs)
+}
+
+func getParent(db, ds string) string {
+	buf := &bytes.Buffer{}
+	call(buf, "noms", "log", "-n", "2", "-oneline", ds)
+	// Output will look like:
+	// abc (Parent def)
+	// def (Parent None)
+	// We could use the first line and grab the Parent value from there, but it could also be Merge,
+	// and it might be None, so easier to just get the 2nd row.
+	lines := strings.SplitN(buf.String(), "\n", 2)
+	if len(lines) != 2 {
+		return ""
+	}
+	hsh := strings.SplitN(lines[0], " ", 2)[0]
+	return fmt.Sprintf("%s::#%s", db, hsh)
+}
+
+func call(stdout io.Writer, name string, arg ...string) error {
+	cmd := exec.Command(name, arg...)
+	fmt.Println("    >", name, strings.Join(arg, " "))
+	cmd.Stdout = stdout
+	cmd.Stderr = os.Stderr
+	err := cmd.Run()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "    ERROR: %s\n", err.Error())
+	}
+	return err
+}
+
+func streamDs(db string) <-chan string {
+	buf := &bytes.Buffer{}
+	err := call(buf, "noms", "ds", db)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "    ERROR: failed to get datasets")
+		os.Exit(-1)
+	}
+
+	out := strings.Trim(buf.String(), " \n")
+	if out == "" {
+		fmt.Fprintln(os.Stderr, "    ERROR: no datasets at", db)
+		os.Exit(-1)
+	}
+
+	datasets := strings.Split(out, "\n")
+
+	ch := make(chan string)
+	go func() {
+		for {
+			ch <- datasets[rand.Intn(len(datasets))]
+		}
+	}()
+	return ch
+}