Add a plugin to welcome new contributors

This plugin will post a welcome message to new contributors when they
submit their first patchset to The Qt Project, also adding
a random selection of four users from a buddy group of reviewers
that have volunteered to help new contributors.

This patch also includes some minor fixups found in related code
discovered during development of this plugin.

Fixes: QTQAINFRA-5973
Change-Id: I1762a1047aa6c72e30b60c7ee5d277cee5750ade
Reviewed-by: Daniel Smith <daniel.smith@qt.io>

5 files changed, 335 insertions, 46 deletions

diff --git a/scripts/gerrit/cherry-pick_automation/gerritRESTTools.js b/scripts/gerrit/cherry-pick_automation/gerritRESTTools.js
index db1cfd0c..a28c8d6a 100644
--- a/scripts/gerrit/cherry-pick_automation/gerritRESTTools.js
+++ b/scripts/gerrit/cherry-pick_automation/gerritRESTTools.js
@@ -258,13 +258,17 @@ function stageCherryPick(parentUuid, cherryPickJSON, customAuth, callback) {
 // Post a comment to the change on the latest revision.
 exports.postGerritComment = postGerritComment;
 function postGerritComment(
-  parentUuid, fullChangeID, revision, message,
+  parentUuid, fullChangeID, revision, message, reviewers,
   notifyScope, customAuth, callback
 ) {
   function _postComment() {
     let url = `${gerritBaseURL("changes")}/${fullChangeID}/revisions/${
       revision || "current"}/review`;
     let data = { message: message, notify: notifyScope || "OWNER_REVIEWERS" };
+    if (reviewers) {
+      // format reviewers as a list of ReviewInput entities
+      data.reviewers = reviewers.map((reviewer) => { return { reviewer: reviewer }; });
+    }
 
     logger.log(
       `POST request to: ${url}\nRequest Body: ${safeJsonStringify(data)}`,
@@ -648,6 +652,37 @@ function addToAttentionSet(parentUuid, changeJSON, user, reason, customAuth, cal
   )
 }
 
+exports.getGroupMembers = getGroupMembers;
+function getGroupMembers(parentUuid, groupId, customAuth, callback) {
+  let url = `${gerritBaseURL("groups")}/${groupId}/members`;
+  logger.log(`GET request to: ${url}`, "debug", parentUuid);
+
+  axios.get(url, { auth: customAuth || gerritAuth })
+  .then(function (response) {
+    logger.log(`Raw response: ${response.data}`, "debug", parentUuid);
+    callback(true, JSON.parse(trimResponse(response.data)));
+  }).catch(function (error) {
+    if (error.response) {
+      // The request was made and the server responded with a status code
+      // that falls out of the range of 2xx
+      logger.log(
+        `An error occurred in GET to "${url}". Error ${error.response.status}: ${
+          error.response.data}`,
+        "error", parentUuid
+      );
+    } else {
+      logger.log(
+        `Failed to get change group members for ${groupId}: ${safeJsonStringify(error)}`,
+        "error", parentUuid
+      );
+    }
+    // Some kind of error occurred. Have the caller take some action to
+    // alert the owner that they need to add reviewers manually.
+    callback(false);
+  });
+
+}
+
 // Query gerrit for the existing reviewers on a change.
 exports.getChangeReviewers = getChangeReviewers;
 function getChangeReviewers(parentUuid, fullChangeID, customAuth, callback) {
@@ -693,12 +728,80 @@ function getChangeReviewers(parentUuid, fullChangeID, customAuth, callback) {
 exports.setChangeReviewers = setChangeReviewers;
 function setChangeReviewers(parentUuid, fullChangeID, reviewers, customAuth, callback) {
   let failedItems = [];
-  if (reviewers.length == 0)  // This function is a no-op if there are no reviewers.
+  if (reviewers.length == 0) { // This function is a no-op if there are no reviewers.
     callback(failedItems);
-  let project = /^((?:\w+-?)+(?:%2F|\/)(?:-?\w)+)/.exec(fullChangeID).pop();
-  let branch = /~(.+)~/.exec(fullChangeID).pop();
+    return
+  }
+  let project = "";
+  let branch = "";
+
+  // Only try to parse strings. If it's not a string, then it's probably
+  // a change number.
+  if (typeof fullChangeID == String) {
+    try {
+      project = /^((?:\w+-?)+(?:%2F|\/)(?:-?\w)+)/.exec(fullChangeID).pop();
+      branch = /~(.+)~/.exec(fullChangeID).pop();
+    } catch (e) {
+      logger.log(
+        `Failed to parse project and branch from ${fullChangeID}: ${e}`,
+        "error", parentUuid
+      );
+      return;
+    }
+  }
+
   let doneCount = 0;
+
   function postReviewer(reviewer) {
+
+    function doPost(url, data) {
+      logger.log(
+        `POST request to ${url}\nRequest Body: ${safeJsonStringify(data)}`,
+        "debug", parentUuid
+      );
+      axios({ method: "post", url: url, data: data, auth: customAuth || gerritAuth })
+        .then(function (response) {
+          logger.log(
+            `Success adding ${reviewer} to ${fullChangeID}\n${response.data}`,
+            "info", parentUuid
+          );
+          doneCount++;
+          if (doneCount == reviewers.length)
+            callback(failedItems);
+        })
+        .catch(function (error) {
+          doneCount++;
+          if (doneCount == reviewers.length)
+            callback(failedItems);
+          if (error.response) {
+            // The request was made and the server responded with a status code
+            // that falls out of the range of 2xx
+            logger.log(
+              `Error in POST to ${url} to add reviewer ${reviewer}: ${
+                error.response.status}: ${error.response.data}`,
+              "error", parentUuid
+            );
+          } else {
+            logger.log(
+              `Error adding a reviewer (${reviewer}) to ${fullChangeID}: ${safeJsonStringify(error)}`,
+              "warn", parentUuid
+            );
+          }
+          failedItems.push(reviewer);
+        });
+      }
+
+    let url = `${gerritBaseURL("changes")}/${fullChangeID}/reviewers`;
+    let data = { reviewer: reviewer };
+
+    if (!project || !branch) {
+      // The fullChangeId passed is probably just a change number.
+      // Try to blindly set the reviewer. The operation will silently fail
+      // if the user does not have rights.
+      doPost(url, data);
+      return;
+    }
+
     checkAccessRights(
       parentUuid, project, branch, reviewer, "read", customAuth,
       function (success, data) {
@@ -709,42 +812,7 @@ function setChangeReviewers(parentUuid, fullChangeID, reviewers, customAuth, cal
           logger.log(`Reason: ${data}`, "debug", parentUuid);
           failedItems.push(reviewer);
         } else {
-          let url = `${gerritBaseURL("changes")}/${fullChangeID}/reviewers`;
-          let data = { reviewer: reviewer };
-          logger.log(
-            `POST request to ${url}\nRequest Body: ${safeJsonStringify(data)}`,
-            "debug", parentUuid
-          );
-          axios({ method: "post", url: url, data: data, auth: customAuth || gerritAuth })
-            .then(function (response) {
-              logger.log(
-                `Success adding ${reviewer} to ${fullChangeID}\n${response.data}`,
-                "info", parentUuid
-              );
-              doneCount++;
-              if (doneCount == reviewers.length)
-                callback(failedItems);
-            })
-            .catch(function (error) {
-              doneCount++;
-              if (doneCount == reviewers.length)
-                callback(failedItems);
-              if (error.response) {
-                // The request was made and the server responded with a status code
-                // that falls out of the range of 2xx
-                logger.log(
-                  `Error in POST to ${url} to add reviewer ${reviewer}: ${
-                    error.response.status}: ${error.response.data}`,
-                  "error", parentUuid
-                );
-              } else {
-                logger.log(
-                  `Error adding a reviewer (${reviewer}) to ${fullChangeID}: ${safeJsonStringify(error)}`,
-                  "warn", parentUuid
-                );
-              }
-              failedItems.push(reviewer);
-            });
+          doPost(url, data);
         }
       }
     );
@@ -1005,3 +1073,56 @@ function findIntegrationIDFromChange(uuid, fullChangeID, customAuth, callback) {
       callback(false);
     })
 }
+
+exports.getContributorChangeCount = getContributorChangeCount;
+function getContributorChangeCount(uuid, contributor, customAuth, callback) {
+  let url = `${gerritBaseURL("changes")}/?q=owner:${contributor}`;
+  logger.log(`GET request for ${url}`, "debug", uuid);
+  axios
+    .get(url, { auth: customAuth || gerritAuth })
+    .then(function (response) {
+      logger.log(`Raw Response: ${response.data}`, "silly", uuid);
+      const changes = JSON.parse(trimResponse(response.data));
+      callback(true, changes.length);
+    })
+    .catch((error) => {
+      logger.log(`Failed to get change count for ${contributor}\n${error}`, "error", uuid);
+      callback(false);
+    })
+}
+
+exports.setHashtags = setHashtags;
+function setHashtags(uuid, fullChangeID, hashtags, customAuth, callback) {
+  let url = `${gerritBaseURL("changes")}/${fullChangeID}/hashtags`;
+  logger.log(`POST add request for ${url}`, "debug", uuid);
+  if (typeof hashtags == "string")
+    hashtags = [hashtags];
+  axios
+    .post(url, {"add": hashtags}, { auth: customAuth || gerritAuth })
+    .then(function (response) {
+      logger.log(`Raw Response: ${response.data}`, "silly", uuid);
+      callback(true);
+    })
+    .catch((error) => {
+      logger.log(`Failed to set hashtag for ${fullChangeID}\n${error}`, "error", uuid);
+      callback(false);
+    })
+}
+
+exports.removeHashtags = removeHashtags;
+function removeHashtags(uuid, fullChangeID, hashtags, customAuth, callback) {
+  let url = `${gerritBaseURL("changes")}/${fullChangeID}/hashtags`;
+  logger.log(`POST remove request for ${url}`, "debug", uuid);
+  if (typeof hashtags == "string")
+    hashtags = [hashtags];
+  axios
+    .post(url, {"remove": hashtags}, { auth: customAuth || gerritAuth })
+    .then(function (response) {
+      logger.log(`Raw Response: ${response.data}`, "silly", uuid);
+      callback(true);
+    })
+    .catch((error) => {
+      logger.log(`Failed to remove hashtag for ${fullChangeID}\n${error}`, "error", uuid);
+      callback(false);
+    })
+}
diff --git a/scripts/gerrit/cherry-pick_automation/plugin_bots/new_contributor_welcome/config.json b/scripts/gerrit/cherry-pick_automation/plugin_bots/new_contributor_welcome/config.json
new file mode 100644
index 00000000..08980744
--- /dev/null
+++ b/scripts/gerrit/cherry-pick_automation/plugin_bots/new_contributor_welcome/config.json
@@ -0,0 +1,5 @@
+{
+    "NEW_CONTRIBUTOR_WELCOME_ENABLED": "",
+    "CONTRIBUTOR_GERRIT_USER": "",
+    "CONTRIBUTOR_GERRIT_PASS": ""
+}
diff --git a/scripts/gerrit/cherry-pick_automation/plugin_bots/new_contributor_welcome/new_contributor_welcome.js b/scripts/gerrit/cherry-pick_automation/plugin_bots/new_contributor_welcome/new_contributor_welcome.js
new file mode 100644
index 00000000..7c2ad08f
--- /dev/null
+++ b/scripts/gerrit/cherry-pick_automation/plugin_bots/new_contributor_welcome/new_contributor_welcome.js
@@ -0,0 +1,163 @@
+/* eslint-disable no-unused-vars */
+// Copyright (C) 2020 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+exports.id = "new_contributor_welcome";
+
+const gerritTools = require("../../gerritRESTTools");
+const config = require("./config.json");
+
+function envOrConfig(ID) {
+  return process.env[ID] || config[ID];
+}
+
+class new_contributor_welcome {
+  constructor(notifier) {
+    this.notifier = notifier;
+    this.logger = notifier.logger;
+    this.retryProcessor = notifier.retryProcessor;
+    this.requestProcessor = notifier.requestProcessor;
+
+    this.gerritAuth = {
+      username: envOrConfig("CONTRIBUTOR_GERRIT_USER"),
+      password: envOrConfig("CONTRIBUTOR_GERRIT_PASS")
+    };
+
+
+    notifier.registerCustomListener(notifier.requestProcessor, "check_new_contributor_reviewers",
+      this.check_new_contributor_reviewers.bind(this));
+    notifier.server.registerCustomEvent(
+      "welcome_new_contributor", "patchset-created",
+      (req) => {
+        // Run a few checks.
+
+        // Is the patchset a new change on patchset 1?
+        if (req.patchSet.number != 1) {
+          return;
+        }
+
+        // Has the user already contributed?
+        gerritTools.getContributorChangeCount(req.uuid, req.change.owner.username, this.gerritAuth,
+          (success, count) => {
+            if (!success) {
+              this.logger.log("Failed to get contributor info for " + req.change.owner.username
+                + " on " + req.change.number, "error", req.uuid);
+              return;
+            }
+            if (count > 1) {
+              // Already contributed, no need to welcome.
+              return;
+            }
+
+            // This is the first change the user has submitted.
+            // Wait two minutes to see if they add reviewers.
+            this.retryProcessor.addRetryJob("WELCOME", "check_new_contributor_reviewers",
+              [req], 120000);
+          })
+      }
+    );
+    this.logger.log("Initialized New contributor welcome bot", "info", "SYSTEM");
+  }
+
+  check_new_contributor_reviewers(req) {
+    // Get the current reviewers of the change.
+    gerritTools.getChangeReviewers(req.uuid, req.change.number, this.gerritAuth,
+      (success, reviewers) => {
+        if (!success) {
+          this.logger.log("Failed to get change info for " + req.change.number,
+            "error", req.uuid);
+          return;
+        }
+        // Check if the change has reviewers. Sanity bot will always be added as a reviewer.
+        reviewers = reviewers.filter(reviewer => reviewer != "qt_sanitybot@qt-project.org");
+        this.logger.log("Existing reviewers: [" + reviewers + "]", "verbose", req.uuid);
+        if (reviewers.length > 0) {
+          // The change has reviewers, no need to welcome.
+          return;
+        }
+
+        // The change has no reviewers, send a welcome message.
+        this.send_welcome_message(req, req.change.project);
+      })
+  }
+
+  send_welcome_message(req) {
+    const user = req.change.owner.name || req.change.owner.username;
+    const message = `Welcome to The Qt Project, ${user}! `
+      + "Thank you for your contribution!\n\n"
+      + "In order to get your change merged, it needs to be reviewed and approved first.\n"
+      + "Since you are new to the project, we've added a few reviewers for you that can help"
+      + " you with your first contribution and find a reviewer who knows this code well."
+      + " If you have any questions about getting set up with Qt, or anything else in our review"
+      + " process, feel free to ask them.\n\n"
+      + "In case you haven't read it yet, please take a look at our "
+      + "[Contribution guide](https://wiki.qt.io/Qt_Contribution_Guidelines),"
+      + " [Coding style](https://wiki.qt.io/Qt_Coding_Style), and"
+      + " [Contributions homepage](https://wiki.qt.io/Contribute).\n\n"
+      + "Note that this change has been set to \"Ready for review\" automatically so that the added"
+      + " reviewers can see it. If you are not ready for review yet, please set the change back to"
+      + " \"Work in progress\" using the menu in the top-right of the page.\n\n"
+      + "And again, welcome to The Qt Project! Your contribution is greatly appreciated!";
+
+    // Add the reviewers.
+    gerritTools.postGerritComment(req.uuid, req.change.number, undefined, message,
+      undefined, undefined, this.gerritAuth,
+      (success, data) => {
+        if (!success) {
+          this.logger.log("Failed to post welcome message for " + req.change.number,
+            "error", req.uuid);
+          return;
+        }
+        // Get group members
+        // Gerrit group for review buddies: eb1d5ff38b9cfe20c4cfada58b5bf8ba246ad6ab
+        // AKA: "New Contributors Welcome Buddies"
+        gerritTools.getGroupMembers(req.uuid, "New Contributors Welcome Buddies", this.gerritAuth,
+          (success, members) => {
+            if (!success) {
+              this.logger.log("Failed to get group members for " + req.change.number,
+                "error", req.uuid);
+              return;
+            }
+            members = members.map(member => member.username);
+            // Randomly select 4 reviewers.
+            members = members.sort(() => Math.random() - Math.random()).slice(0, 4);
+            // Add the reviewers.
+            this.logger.log("Adding reviewers [" + members + "] for " + req.change.number,
+              "verbose", req.uuid);
+            gerritTools.setChangeReviewers(req.uuid, req.change.number,
+              members, this.gerritAuth,
+              (failedItems) => {
+                if (failedItems.length > 0) {
+                  this.logger.log("Failed to add reviewers for " + req.change.number,
+                    "error", req.uuid);
+                  return;
+                }
+                this.logger.log("Added reviewers for " + req.change.number,
+                  "verbose", req.uuid);
+              }
+            );
+          }
+        );
+        this.logger.log("Posted welcome message for " + req.change.number,
+          "verbose", req.uuid);
+      }
+    );
+
+    // Also set a hashtag marking the change as from a new contributor.
+    // This makes all changes from new contributors easy to find.
+    // https://codereview.qt-project.org/q/hashtag:new_contributor
+    gerritTools.setHashtags(req.uuid, req.change.number, ["new_contributor"],
+      this.gerritAuth, (success) => {
+        if (!success) {
+          this.logger.log("Failed to set hashtags for " + req.change.number,
+            "error", req.uuid);
+          return;
+        }
+        this.logger.log("Set hashtags for " + req.change.number,
+          "verbose", req.uuid);
+      }
+    );
+  }
+}
+
+module.exports = new_contributor_welcome;
diff --git a/scripts/gerrit/cherry-pick_automation/requestProcessor.js b/scripts/gerrit/cherry-pick_automation/requestProcessor.js
index b9e904cc..12ab828e 100644
--- a/scripts/gerrit/cherry-pick_automation/requestProcessor.js
+++ b/scripts/gerrit/cherry-pick_automation/requestProcessor.js
@@ -1356,7 +1356,7 @@ class requestProcessor extends EventEmitter {
   gerritCommentHandler(parentUuid, fullChangeID, revision, message, notifyScope, customGerritAuth) {
     let _this = this;
     gerritTools.postGerritComment(
-      parentUuid, fullChangeID, revision, message, notifyScope, customGerritAuth,
+      parentUuid, fullChangeID, revision, message, undefined, notifyScope, customGerritAuth,
       function (success, data) {
         if (!success && data == "retry") {
           _this.emit(
diff --git a/scripts/gerrit/cherry-pick_automation/retryProcessor.js b/scripts/gerrit/cherry-pick_automation/retryProcessor.js
index 4293af69..d98d0386 100644
--- a/scripts/gerrit/cherry-pick_automation/retryProcessor.js
+++ b/scripts/gerrit/cherry-pick_automation/retryProcessor.js
@@ -15,7 +15,7 @@ class retryProcessor extends EventEmitter {
     this.requestProcessor = requestProcessor;
   }
 
-  addRetryJob(originalUuid, retryAction, args) {
+  addRetryJob(originalUuid, retryAction, args, delay) {
     let _this = this;
     const retryUuid = uuidv1();
     _this.logger.log(`Setting up ${retryAction}`, "warn", originalUuid);
@@ -27,10 +27,10 @@ class retryProcessor extends EventEmitter {
           `Retry ${retryAction} registered for ${retryUuid}`,
           "verbose", originalUuid
         );
-        // Call retry in 30 seconds.
+        // Call retry in 30 seconds or custom delay time.
         setTimeout(function () {
           _this.emit("processRetry", retryUuid);
-        }, 30000);
+        }, delay || 30000);
       }
     );
   }
@@ -39,7 +39,7 @@ class retryProcessor extends EventEmitter {
   // the process where it left off.
   processRetry(uuid, callback) {
     let _this = this;
-    _this.logger.log(`Processing retry event with uuid ${uuid}`);
+    _this.logger.log(`Processing retry event with uuid ${uuid}`, "debug", "RETRY");
     function deleteRetryRecord() {
       postgreSQLClient.deleteDBEntry("retry_queue", "uuid", uuid, function (success, data) {});
     }
@@ -49,7 +49,7 @@ class retryProcessor extends EventEmitter {
         deleteRetryRecord();
         let args = toolbox.decodeBase64toJSON(rows[0].args);
         _this.logger.log(
-          `Processing retryRequest "${rows[0].retryAction}" for ${uuid} with args: ${args}`,
+          `Processing retryRequest "${rows[0].retryaction}" for ${uuid} with args: ${args}`,
           "debug"
         );
         _this.requestProcessor.emit(rows[0].retryaction, ...args);