From 00b1a53bb38945c627030b5c7f1e6f1658f86f77 Mon Sep 17 00:00:00 2001
From: Eli Bendersky <eliben@users.noreply.github.com>
Date: Tue, 28 May 2019 12:15:51 -0700
Subject: [PATCH] testing: initial code for release helper tool (#2114)

Updates #886
---
 internal/testing/releasehelper.go             | 171 ++++++++++++++++++
 .../content/internal/testing/_index.md        |   4 +
 2 files changed, 175 insertions(+)
 create mode 100644 internal/testing/releasehelper.go
 create mode 100644 internal/website/content/internal/testing/_index.md

diff --git a/internal/testing/releasehelper.go b/internal/testing/releasehelper.go
new file mode 100644
index 0000000000..463a499508
--- /dev/null
+++ b/internal/testing/releasehelper.go
@@ -0,0 +1,171 @@
+// Copyright 2019 The Go Cloud Development Kit Authors
+//
+// 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
+//
+//     https://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.
+
+// Helper tool for creating new releases of the Go CDK. See -help for details.
+package main
+
+import (
+	"bufio"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+// TODO(eliben): add bumpversion flag that bumps version by 1, or to a version
+// given on the command line
+var helpText string = `
+Helper tool for creating new releases of the Go CDK.
+
+Automates the modifications required in the project's
+go.mod files to create an test new releases.
+
+The tool processes all modules listed in the 'allmodules'
+file. For each module it handles all dependencies on
+other gocloud.dev modules.
+
+-replace adds 'replace' directives to point to local versions
+for testing. -dropreplace removes these directives.
+
+Run it from the root directory of the project.
+
+Usage:
+`
+
+var doReplace = flag.Bool("replace", false, "add replace directives")
+var doDropReplace = flag.Bool("dropreplace", false, "drop replace directives")
+
+// cmdCheck invokes the command given in s, echoing the invocation to stdout.
+// It checks that the command was successful and returns its standard output.
+// If the command returned a non-0 status, log.Fatal is invoked.
+func cmdCheck(s string) []byte {
+	fmt.Printf(" -> %s\n", s)
+	fields := strings.Fields(s)
+	if len(fields) < 1 {
+		log.Fatal(`Expected "command <arguments>"`)
+	}
+	b, err := exec.Command(fields[0], fields[1:]...).Output()
+	if exiterr, ok := err.(*exec.ExitError); ok {
+		log.Fatalf("%s; stderr: %s\n", err, string(exiterr.Stderr))
+	} else if err != nil {
+		log.Fatal("exec.Command", err)
+	}
+	return b
+}
+
+// These types are taken from "go mod help edit", in order to parse the JSON
+// output of `go mod edit -json`.
+type GoMod struct {
+	Module  Module
+	Go      string
+	Require []Require
+	Exclude []Module
+	Replace []Replace
+}
+
+type Module struct {
+	Path    string
+	Version string
+}
+
+type Require struct {
+	Path     string
+	Version  string
+	Indirect bool
+}
+
+type Replace struct {
+	Old Module
+	New Module
+}
+
+// parseModuleInfo parses module information from a go.mod file at path.
+func parseModuleInfo(path string) GoMod {
+	rawJson := cmdCheck("go mod edit -json " + path)
+	var modInfo GoMod
+	err := json.Unmarshal(rawJson, &modInfo)
+	if err != nil {
+		log.Fatal(err)
+	}
+	return modInfo
+}
+
+func runOnGomod(path string) {
+	gomodPath := filepath.Join(path, "go.mod")
+	fmt.Println("Processing", gomodPath)
+	modInfo := parseModuleInfo(gomodPath)
+
+	base := "gocloud.dev"
+
+	for _, r := range modInfo.Require {
+		// Find requirements on modules within the gocloud.dev tree.
+		if strings.HasPrefix(r.Path, base) {
+			// Find the relative path from 'path' and the module required here.
+			var reqPath string
+			if r.Path == base {
+				reqPath = "."
+			} else {
+				reqPath = strings.TrimPrefix(r.Path, base)
+			}
+			rel, err := filepath.Rel(path, reqPath)
+			if err != nil {
+				log.Fatal(err)
+			}
+			// When path is '.', filepath.Rel will append a /. to the result and we
+			// may get paths like ../../.
+			if strings.HasSuffix(rel, "/.") {
+				rel, _ = filepath.Split(rel)
+			}
+
+			if *doReplace {
+				cmdCheck(fmt.Sprintf("go mod edit -replace=%s=%s %s", r.Path, rel, gomodPath))
+			} else if *doDropReplace {
+				cmdCheck(fmt.Sprintf("go mod edit -dropreplace=%s %s", r.Path, gomodPath))
+			}
+		}
+	}
+}
+
+func main() {
+	flag.Usage = func() {
+		fmt.Fprintf(flag.CommandLine.Output(), helpText)
+		flag.PrintDefaults()
+	}
+
+	flag.Parse()
+	if *doReplace && *doDropReplace {
+		log.Fatal("Expected only one of -replace/-dropreplace")
+	}
+
+	f, err := os.Open("allmodules")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	input := bufio.NewScanner(f)
+	input.Split(bufio.ScanLines)
+	for input.Scan() {
+		if len(input.Text()) > 0 && !strings.HasPrefix(input.Text(), "#") {
+			runOnGomod(input.Text())
+		}
+	}
+
+	if input.Err() != nil {
+		log.Fatal(input.Err())
+	}
+}
diff --git a/internal/website/content/internal/testing/_index.md b/internal/website/content/internal/testing/_index.md
new file mode 100644
index 0000000000..4070b9b409
--- /dev/null
+++ b/internal/website/content/internal/testing/_index.md
@@ -0,0 +1,4 @@
+---
+title: gocloud.dev/internal/testing
+type: pkg
+---