BugChomper utility - rewrite in Go

tools/bug_chomper/src/issue_tracker/issue_tracker.go

Index: tools/bug_chomper/src/issue_tracker/issue_tracker.go
diff --git a/tools/bug_chomper/src/issue_tracker/issue_tracker.go b/tools/bug_chomper/src/issue_tracker/issue_tracker.go
new file mode 100644
index 0000000000000000000000000000000000000000..11f478f29f61cda57114ac26f25bb580806d2f57
--- /dev/null
+++ b/tools/bug_chomper/src/issue_tracker/issue_tracker.go
@@ -0,0 +1,272 @@
+// Copyright (c) 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/*
+	Utilities for interacting with the GoogleCode issue tracker.
+
+	Example usage:
+		issueTracker := issue_tracker.MakeIssueTraker(myOAuthConfigFile)
+		authURL := issueTracker.MakeAuthRequestURL()
+		// Visit the authURL to obtain an authorization code.
+		issueTracker.UpgradeCode(code)
+		// Now issueTracker can be used to retrieve and edit issues.
+*/
+package issue_tracker
+
+import (
+	"bytes"
+	"code.google.com/p/goauth2/oauth"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"strconv"
+)
+
+// BugPriorities are the possible values for "Priority-*" labels for issues.
+var BugPriorities = []string{"Critical", "High", "Medium", "Low", "Never"}
+
+const apiScope = "https://www.googleapis.com/auth/projecthosting"
+const apiURL = "https://www.googleapis.com/projecthosting/v2/projects/"
+const issueURL = "https://code.google.com/p/skia/issues/detail?id="
+
+// Enum for determining whether a label has been added, removed, or is
+// unchanged.
+const (
+	labelNew  = iota
+	labelOld  = iota
+	labelBoth = iota
+)
+
+// loadOAuthConfig reads the OAuth given config file path and returns an
+// appropriate oauth.Config.
+func loadOAuthConfig(oauthConfigFile string) (*oauth.Config, error) {
+	fileContents, err := ioutil.ReadFile(oauthConfigFile)
+	if err != nil {
+		return nil, err

[jcgregorio, 2014/05/07 19:32:25]

For cases where you return errors like this you should use Errorf to add context
to the error:

   return nil, fmt.Errorf("failed to read OAuth config file: %s", err)

Don't begin the error message with upper case, this allows the errors to nest
context cleanly.

[borenet, 2014/05/07 22:27:37]

Done.

+	}
+	var decodedJson map[string]struct {
+		AuthURL      string `json:"auth_uri"`
+		ClientId     string `json:"client_id"`
+		ClientSecret string `json:"client_secret"`
+		TokenURL     string `json:"token_uri"`
+	}
+	err = json.Unmarshal(fileContents, &decodedJson)
+	if err != nil {
+		return nil, err
+	}
+	config, ok := decodedJson["web"]
+	if !ok {
+		return nil, err
+	}
+	return &oauth.Config{
+		ClientId:     config.ClientId,
+		ClientSecret: config.ClientSecret,
+		Scope:        apiScope,
+		AuthURL:      config.AuthURL,
+		TokenURL:     config.TokenURL,
+	}, nil
+}
+
+// Issue contains information about an issue.
+type Issue struct {
+	Id      int      `json:"id"`
+	Project string   `json:"projectId"`
+	Title   string   `json:"title"`
+	Labels  []string `json:"labels"`
+}
+
+// URL returns the URL of a given issue.
+func (i *Issue) URL() string {

[jcgregorio, 2014/05/07 19:32:25]

Doesn't need to be *Issue, just Issue, since you aren't modifying i.

[borenet, 2014/05/07 22:27:37]

Done, but I thought this performed a copy if it's not a pointer?

[jcgregorio, 2014/05/08 15:11:56]

That's for arguments, in the case of the 

On 2014/05/07 22:27:37, borenet wrote:
That's for arguments, it's slightly different in the case of the receiver, using
(i T) is similar to declaring a function const in C++, it can't modify the
underlying receiver, while declaring it (i *T) means that the method can modify
the receiver. Note that in Go the receiver can be more general than a C++
class/struct, it just needs to be a type.

+	return issueURL + strconv.Itoa(i.Id)
+}
+
+// IssueList represents a list of issues from the IssueTracker.
+type IssueList struct {
+	TotalResults int      `json:"totalResults"`
+	Items        []*Issue `json:"items"`
+}
+
+// IssueTracker is the primary point of contact with the issue tracker,
+// providing methods for authenticating to and interacting with it.
+type IssueTracker struct {
+	oauthConfig    *oauth.Config
+	oauthTransport *oauth.Transport
+}
+
+// MakeIssueTracker creates and returns an IssueTracker with authentication
+// configuration from the given authConfigFile.
+func MakeIssueTracker(authConfigFile string) (*IssueTracker, error) {
+	oauthConfig, err := loadOAuthConfig(authConfigFile)
+	if err != nil {
+		return nil, errors.New(
+			"Unable to read auth config file: " + err.Error())
+	}
+	return &IssueTracker{
+		oauthConfig:    oauthConfig,
+		oauthTransport: &oauth.Transport{Config: oauthConfig},
+	}, nil
+}
+
+// MakeAuthRequestURL returns an authentication request URL which can be used
+// to obtain an authorization code via user sign-in.
+func (it *IssueTracker) MakeAuthRequestURL(redirectURL string) string {
+	it.oauthConfig.RedirectURL = redirectURL
+	return it.oauthConfig.AuthCodeURL(redirectURL)
+}
+
+// IsAuthenticated determines whether the IssueTracker has sufficient
+// permissions to retrieve and edit Issues.
+func (it *IssueTracker) IsAuthenticated() bool {
+	return it.oauthTransport.Token != nil
+}
+
+// UpgradeCode exchanges the single-use authorization code, obtained by
+// following the URL obtained from IssueTracker.MakeAuthRequestURL, for a
+// multi-use, session token. This is required before IssueTracker can retrieve
+// and edit issues.
+func (it *IssueTracker) UpgradeCode(code string) error {
+	token, err := it.oauthTransport.Exchange(code)
+	if err == nil {
+		it.oauthTransport.Token = token
+	}
+	return err
+}
+
+// GetBug retrieves the Issue with the given ID from the IssueTracker.
+func (it *IssueTracker) GetBug(project string, id int) (*Issue, error) {
+	if !it.IsAuthenticated() {
+		return nil, errors.New("User is not authenticated!")
+	}
+	requestURL := apiURL + project + "/issues/" + strconv.Itoa(id)
+	resp, err := it.oauthTransport.Client().Get(requestURL)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	body, _ := ioutil.ReadAll(resp.Body)
+	if resp.StatusCode != http.StatusOK {
+		return nil, errors.New(fmt.Sprintf(
+			"Issue tracker returned code %d:%v",
+			resp.StatusCode, string(body)))
+	}
+	var issue Issue
+	err = json.Unmarshal(body, &issue)
+	if err != nil {
+		return nil, err
+	}
+	return &issue, nil
+}
+
+// GetBugs retrieves all Issues with the given owner from the IssueTracker,
+// returning an IssueList.
+func (it *IssueTracker) GetBugs(
+	project string, owner string) (*IssueList, error) {
+	if !it.IsAuthenticated() {
+		return nil, errors.New("User is not authenticated!")
+	}
+	params := map[string]string{
+		"owner":      url.QueryEscape(owner),
+		"can":        "open",
+		"maxResults": "9999",
+	}
+	requestURL := apiURL + project + "/issues?"
+	first := true
+	for k, v := range params {
+		if first {
+			first = false
+		} else {
+			requestURL += "&"
+		}
+		requestURL += k + "=" + v
+	}
+	resp, err := it.oauthTransport.Client().Get(requestURL)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	body, _ := ioutil.ReadAll(resp.Body)
+	if resp.StatusCode != http.StatusOK {
+		return nil, errors.New(fmt.Sprintf(
+			"Issue tracker returned code %d:%v",
+			resp.StatusCode, string(body)))
+	}
+
+	var bugList IssueList
+	err = json.Unmarshal(body, &bugList)
+	if err != nil {
+		return nil, err
+	}
+	return &bugList, nil
+}
+
+// SubmitIssueChanges creates a comment on the given Issue which modifies it
+// according to the contents of the passed-in Issue struct.
+func (it *IssueTracker) SubmitIssueChanges(
+	issue *Issue, comment string) error {
+	errPrefix := "Error updating issue " + strconv.Itoa(issue.Id) + ": "
+	if !it.IsAuthenticated() {
+		return errors.New(errPrefix + "User is not authenticated!")
+	}
+	oldIssue, err := it.GetBug(issue.Project, issue.Id)
+	if err != nil {
+		return err
+	}
+	postData := struct {
+		Content string `json:"content"`
+		Updates struct {
+			Title  *string  `json:"summary"`
+			Labels []string `json:"labels"`
+		} `json:"updates"`
+	}{}
+	postData.Content = comment
+	if issue.Title != oldIssue.Title {
+		postData.Updates.Title = &issue.Title
+	}
+	// TODO(borenet): Add other issue attributes, eg. Owner.
+	labels := make(map[string]int)
+	for _, label := range issue.Labels {
+		labels[label] = labelNew
+	}
+	for _, label := range oldIssue.Labels {
+		if _, ok := labels[label]; ok {
+			labels[label] = labelBoth
+		} else {
+			labels[label] = labelOld
+		}
+	}
+	labelChanges := make([]string, 0)
+	for labelName, present := range labels {
+		if present == labelOld {
+			labelChanges = append(labelChanges, "-"+labelName)
+		} else if present == labelNew {
+			labelChanges = append(labelChanges, labelName)
+		}
+	}
+	if len(labelChanges) > 0 {
+		postData.Updates.Labels = labelChanges
+	}
+
+	postBytes, err := json.Marshal(&postData)
+	if err != nil {
+		return err
+	}
+	requestURL := apiURL + issue.Project + "/issues/" +
+		strconv.Itoa(issue.Id) + "/comments"
+	resp, err := it.oauthTransport.Client().Post(
+		requestURL, "application/json", bytes.NewReader(postBytes))
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	body, _ := ioutil.ReadAll(resp.Body)
+	if resp.StatusCode != http.StatusOK {
+		return errors.New(fmt.Sprintf(
+			"Issue tracker returned code %d:%v",
+			resp.StatusCode, string(body)))
+	}
+	return nil
+}