BugChomper utility - rewrite in Go

tools/bug_chomper/src/issue_tracker/issue_tracker.go

+// 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
+}