Add --debug flag to upload commands

This is useful if you want to figure out something that might not be
working. We decided to use stderr so that you can turn debugging on
without breaking your happo-ci scripts.

README.md

@@ -270,11 +270,19 @@ the argument to `happo upload_diffs`. E.g.
 happo upload "https://test.example"
 ```
 
+To debug uploading, you can use the `--debug` flag. Additional information will
+then be printed to `stderr`.
+
 ### `happo upload-test`
 
 Uploads a small text file to an AWS S3 Account. This is useful if you want to
 test your S3 configuration. Uses the same configuration as [`happo
-upload`](#happo-upload-triggeredbyurl) does.
+upload`](#happo-upload-triggeredbyurl) does. As with `happo upload`, you can
+apply a `--debug` flag here for a more verbose output.
+
+```sh
+happo upload-test --debug
+```
 
 ## Running in a CI environment
 

src/server/S3Uploader.js

@@ -12,13 +12,15 @@ const {
 } = process.env;
 
 module.exports = class S3Uploader {
-  constructor() {
-    process.stdout.write(`Initializing S3 configuration for ${S3_ACCESS_KEY_ID}\n`);
+  constructor({ debug } = {}) {
+    this.debug = debug;
+    this.debugLog(`Initializing S3 configuration for ${S3_ACCESS_KEY_ID}\n`);
+
     AWS.config = new AWS.Config({
       accessKeyId: S3_ACCESS_KEY_ID,
       secretAccessKey: S3_SECRET_ACCESS_KEY,
       region: S3_REGION || 'us-west-2',
-      logger: process.stdout,
+      logger: debug && process.stderr,
     });
 
     this.s3 = new AWS.S3();
@@ -28,7 +30,17 @@ module.exports = class S3Uploader {
       crypto.randomBytes(16).toString('hex'),
     ].filter(Boolean).join('/');
 
-    process.stdout.write(`Setting S3 directory to ${this.directory}\n`);
+    this.debugLog(`Setting S3 directory to ${this.directory}\n`);
+  }
+
+  debugLog(message) {
+    if (!this.debug) {
+      return;
+    }
+
+    // We print to stderr to avoid messing with the end result (the link to the
+    // uploaded HTML file)
+    process.stderr.write(message);
   }
 
   /**
@@ -38,17 +50,17 @@ module.exports = class S3Uploader {
    */
   prepare() {
     return new Promise((resolve, reject) => {
-      process.stdout.write(`Checking for bucket ${Bucket}\n`);
+      this.debugLog(`Checking for bucket ${Bucket}\n`);
 
       this.s3.headBucket({ Bucket }, (headErr) => {
         if (headErr) {
-          process.stdout.write(`Bucket not found, creating new bucket ${Bucket}\n`);
+          this.debugLog(`Bucket not found, creating new bucket ${Bucket}\n`);
           this.s3.createBucket({ Bucket }, (createErr) => {
             if (createErr) {
-              process.stderr.write(`Bucket creation failed ${Bucket}\n`);
+              this.debugLog(`Bucket creation failed ${Bucket}\n`);
               reject(createErr);
             } else {
-              process.stdout.write(`Bucket creation successful ${Bucket}\n`);
+              this.debugLog(`Bucket creation successful ${Bucket}\n`);
               resolve();
             }
           });
@@ -82,10 +94,10 @@ module.exports = class S3Uploader {
         Key: `${this.directory}/${fileName}`,
       };
 
-      process.stdout.write('Attempting upload\n');
+      this.debugLog('Attempting upload\n');
       this.s3.upload(uploadParams, (err, { Location }) => {
         if (err) {
-          process.stderr.write('Upload failed\n');
+          this.debugLog('Upload failed\n');
           reject(err);
         } else {
           resolve(Location);

src/server/cli.js

@@ -48,18 +48,19 @@ commander.command('review-demo').action(() => {
   });
 });
 
-commander.command('upload [<triggeredByUrl>]').action((triggeredByUrl) => {
-  uploadLastResult(triggeredByUrl)
-    .then((url) => {
-      if (url) {
-        console.log(url);
-      }
-    })
-    .catch(logAndExit);
-});
+commander.command('upload [<triggeredByUrl>]').option('--debug').action(
+  (triggeredByUrl, { debug }) => {
+    uploadLastResult(triggeredByUrl, { debug })
+      .then((url) => {
+        if (url) {
+          console.log(url);
+        }
+      })
+      .catch(logAndExit);
+  });
 
-commander.command('upload-test').action(() => {
-  const uploader = new S3Uploader();
+commander.command('upload-test').option('--debug').action(({ debug }) => {
+  const uploader = new S3Uploader({ debug });
   uploader.prepare()
     .then(() => {
       uploader.upload({

src/server/uploadLastResult.js

@@ -61,10 +61,12 @@ function uploadHTMLFile({ uploader, diffImages, newImages, triggeredByUrl }) {
 }
 
 /**
+ * @param {String} triggeredByUrl
+ * @param {Boolean} options.debug
  * @return {Promise} that resolves with a URL to the html document uploaded to
  *   s3.
  */
-module.exports = function uploadLastResult(triggeredByUrl) {
+module.exports = function uploadLastResult(triggeredByUrl, { debug }) {
   return new Promise((resolve, reject) => {
     const { diffImages, newImages } = getLastResultSummary();
 
@@ -73,7 +75,7 @@ module.exports = function uploadLastResult(triggeredByUrl) {
       return;
     }
 
-    const uploader = new S3Uploader();
+    const uploader = new S3Uploader({ debug });
     uploader.prepare().then(() => {
       const uploadPromises = [];
       diffImages.forEach((image) => {