Fix groovecoder#79: Never post the same comment twice

lib/commenter.js

@@ -5,39 +5,87 @@
  * create_pull_request_comment.
  */
 
+var Q = require('q');
 var request = require('request');
 
 var config = require('./config');
+var models = require('../models');
 
 /**
  * Post a line comment on a particular pull request. commentURL should be an
  * instance of review_comments_url.
  * https://developer.github.com/v3/activity/events/types/#pullrequestevent
  */
-function postPullRequestComment(commentURL, comment, filename, commitSHA, line, done) {
-
-    request({
-        url: commentURL,
-        method: 'POST',
-        headers: {
-            'User-Agent': config.brand,
-            'Authorization': 'token ' + config.token
-        },
-        body: JSON.stringify({
-            body: comment,
-            path: filename,
-            commit_id: commitSHA,
-            position: line
-        })
-    }, function(error, response) {
-        // If the comment could not be submitted, notify Redis so that the job
-        // can be re-attempted later. Otherwise, mark the job as done.
-        if (error || response.statusCode === 403) {
-            return done(new Error('Comment could not be submitted'));
-        } else {
-            done();
+function postPullRequestComment(commentURL, commitSHA, repo, pr, filename, line, comment, incompatibleFeature, done) {
+    var alreadyCommented = commentExists(repo, pr, filename, line, incompatibleFeature);
+    alreadyCommented.then(function(alreadyCommented) {
+        if (!alreadyCommented) {
+            request({
+                url: commentURL,
+                method: 'POST',
+                headers: {
+                    'User-Agent': config.brand,
+                    'Authorization': 'token ' + config.token
+                },
+                body: JSON.stringify({
+                    body: comment,
+                    path: filename,
+                    commit_id: commitSHA,
+                    position: line
+                })
+            }, function(error, response) {
+                // If the comment could not be submitted, notify Redis so that the job
+                // can be re-attempted later. Otherwise, mark the job as done.
+                if (error || response.statusCode === 403) {
+                    return done(new Error('Comment could not be submitted'));
+                } else {
+                    models.Comment.create({
+                        repo: repo,
+                        pr: pr,
+                        filename: filename,
+                        line: line,
+                        feature: incompatibleFeature
+                    }).then(function() {
+                        done();
+                    });
+                }
+            });
+
         }
     });
 }
 
+/**
+ * Return true if a comment has already been posted about this incompatibility.
+ */
+function commentExists(repo, pr, filename, line, incompatibleFeature) {
+    var deferred = Q.defer();
+
+    models.Comment.count({
+        where: {
+            repo: repo,
+            pr: pr,
+            filename: filename,
+            line: line,
+            feature: incompatibleFeature
+        }
+    }).then(
+        // Success callback (a matching comment was found)
+        function(count) {
+            if (count > 0) {
+                deferred.resolve(true);
+            } else {
+                deferred.resolve(false);
+            }
+        },
+
+        // Failure callback (no matching comments were found)
+        function(error) {
+            deferred.reject(error);
+        }
+    );
+
+    return deferred.promise;
+}
+
 exports.postPullRequestComment = postPullRequestComment;

migrations/20160121091841-create-comment.js

@@ -0,0 +1,39 @@
+'use strict';
+module.exports = {
+    up: function(queryInterface, Sequelize) {
+        return queryInterface.createTable('Comments', {
+            id: {
+                allowNull: false,
+                autoIncrement: true,
+                primaryKey: true,
+                type: Sequelize.INTEGER
+            },
+            repo: {
+                type: Sequelize.TEXT
+            },
+            pr: {
+                type: Sequelize.INTEGER
+            },
+            filename: {
+                type: Sequelize.TEXT
+            },
+            line: {
+                type: Sequelize.INTEGER
+            },
+            feature: {
+                type: Sequelize.TEXT
+            },
+            createdAt: {
+                allowNull: false,
+                type: Sequelize.DATE
+            },
+            updatedAt: {
+                allowNull: false,
+                type: Sequelize.DATE
+            }
+        });
+    },
+    down: function(queryInterface, Sequelize) {
+        return queryInterface.dropTable('Comments');
+    }
+};

models/comment.js

@@ -0,0 +1,17 @@
+'use strict';
+module.exports = function(sequelize, DataTypes) {
+    var Comment = sequelize.define('Comment', {
+        repo: DataTypes.TEXT,
+        pr: DataTypes.INTEGER,
+        filename: DataTypes.TEXT,
+        line: DataTypes.INTEGER,
+        feature: DataTypes.TEXT
+    }, {
+        classMethods: {
+            associate: function(models) {
+                // associations can be defined here
+            }
+        }
+    });
+    return Comment;
+};

routes/hook/index.js

@@ -80,9 +80,12 @@ function processPullRequest(destinationRepo, originRepo, originBranch, prNumber,
                     var commentJob = redisQueue.create('comment', {
                         commentURL: commentURL,
                         sha: currentCommit.sha,
+                        repo: destinationRepo,
+                        pr: prNumber,
                         filename: file.filename,
                         line: line,
-                        comment: comment
+                        comment: comment,
+                        incompatibleFeature: incompatibility.featureData.title
                     });
 
                     // If the comment is rejected, re-attempt several times with

worker.js

@@ -23,7 +23,7 @@ redisQueue.process('comment', function(job, done) {
     }
 
     setTimeout(function() {
-        commenter.postPullRequestComment(job.data.commentURL, job.data.comment, job.data.filename, job.data.sha, job.data.line, done);
+        commenter.postPullRequestComment(job.data.commentURL, job.data.sha, job.data.repo, job.data.pr, job.data.filename, job.data.line, job.data.comment, job.data.incompatibleFeature, done);
         lastCommentTimestamp = Date.now(); // Use a new, fresh timestamp
     }, waitRemaining);
 });