Move nightly upload script into Mach

Now that MinGW and MSYS have been removed from the Windows builders,
bash is not available to run the previous upload_nightlies.sh script.
Convert the script to Python 2 for cross-platform support.
Additionally, switch to the `boto3` library for easy uploading
without needing to install `s3cmd`,
and move the code into mach for easy `boto3` installation
as the new `./mach upload-nightly` command.

Also, hard-code the paths to the packages instead of using
globs to look for them, as the paths are static.
(The paths used to contain timestamps,
but we now insert timestamps when uploading to S3
to improve reproducibility.)

python/requirements.txt

@@ -24,4 +24,7 @@ ply == 3.8
 # For Cross-platform colored terminal text
 colorama == 0.3.7
 
+# For package uploading
+boto3 == 1.4.4
+
 -e python/tidy

python/servo/package_commands.py

@@ -7,13 +7,17 @@
 # option. This file may not be copied, modified, or distributed
 # except according to those terms.
 
-from __future__ import print_function, unicode_literals
+from __future__ import absolute_import, print_function, unicode_literals
 
+from datetime import datetime
+import hashlib
 import json
 import os
 import os.path as path
 import shutil
 import subprocess
+import sys
+import tempfile
 
 from mach.decorators import (
     CommandArgument,
@@ -35,6 +39,26 @@ from servo.command_base import (
 from servo.util import delete
 
 
+PACKAGES = {
+    'android': [
+        'target/arm-linux-androideabi/release/servo.apk',
+    ],
+    'linux': [
+        'target/release/servo-tech-demo.tar.gz',
+    ],
+    'mac': [
+        'target/release/servo-tech-demo.dmg',
+    ],
+    'macbrew': [
+        'target/release/brew/servo.tar.gz',
+    ],
+    'windows-msvc': [
+        r'target\release\msi\Servo.msi',
+        r'target\release\msi\Servo.zip',
+    ],
+}
+
+
 def otool(s):
     o = subprocess.Popen(['/usr/bin/otool', '-L', s], stdout=subprocess.PIPE)
     for l in o.stdout:
@@ -364,3 +388,99 @@ class PackageCommands(CommandBase):
 
         print(" ".join(exec_command))
         return subprocess.call(exec_command, env=self.build_env())
+
+    @Command('upload-nightly',
+             description='Upload Servo nightly to S3',
+             category='package')
+    @CommandArgument('platform',
+                     choices=PACKAGES.keys(),
+                     help='Package platform type to upload')
+    def upload_nightly(self, platform):
+        import boto3
+
+        def nightly_filename(package, timestamp):
+            return '{}-{}'.format(
+                timestamp.isoformat() + 'Z',  # The `Z` denotes UTC
+                path.basename(package)
+            )
+
+        def upload_to_s3(platform, package, timestamp):
+            s3 = boto3.client('s3')
+            BUCKET = 'servo-builds'
+
+            nightly_dir = 'nightly/{}'.format(platform)
+            filename = nightly_filename(package, timestamp)
+            package_upload_key = '{}/{}'.format(nightly_dir, filename)
+            extension = path.basename(package).partition('.')[2]
+            latest_upload_key = '{}/servo-latest.{}'.format(nightly_dir, extension)
+
+            s3.upload_file(package, BUCKET, package_upload_key)
+            copy_source = {
+                'Bucket': BUCKET,
+                'Key': package_upload_key,
+            }
+            s3.copy(copy_source, BUCKET, latest_upload_key)
+
+        def update_brew(package, timestamp):
+            print("Updating brew formula")
+
+            package_url = 'https://download.servo.org/nightly/macbrew/{}'.format(
+                nightly_filename(package, timestamp)
+            )
+            with open(package) as p:
+                digest = hashlib.sha256(p.read()).hexdigest()
+
+            brew_version = timestamp.strftime('%Y.%m.%d')
+
+            with tempfile.TemporaryDirectory(prefix='homebrew-servo') as tmp_dir:
+                def call_git(cmd, **kwargs):
+                    subprocess.check_call(
+                        ['git', '-C', tmp_dir] + cmd,
+                        **kwargs
+                    )
+
+                call_git([
+                    'clone',
+                    'https://github.com/servo/homebrew-servo.git',
+                    '.',
+                ])
+
+                script_dir = path.dirname(path.realpath(__file__))
+                with open(path.join(script_dir, 'servo-binary-formula.rb.in')) as f:
+                    formula = f.read()
+                formula = formula.replace('PACKAGEURL', package_url)
+                formula = formula.replace('SHA', digest)
+                formula = formula.replace('VERSION', brew_version)
+                with open(path.join(tmp_dir, 'Formula', 'servo-bin.rb')) as f:
+                    f.write(formula)
+
+                call_git(['add', path.join('.', 'Formula', 'servo-bin.rb')])
+                call_git([
+                    '-c', 'user.name=Tom Servo',
+                    '-c', 'user.email=servo@servo.org',
+                    'commit',
+                    '--message=Version Bump: {}'.format(brew_version),
+                ])
+
+                token = os.environ['GITHUB_HOMEBREW_TOKEN']
+                call_git([
+                    'push',
+                    '-qf',
+                    'https://{}@github.com/servo/homebrew-servo.git'.format(token),
+                    'master',
+                ], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+
+        timestamp = datetime.utcnow().replace(microsecond=0)
+        for package in PACKAGES[platform]:
+            if not path.isfile(package):
+                print("Could not find package for {} at {}".format(
+                    platform,
+                    package
+                ), file=sys.stderr)
+                return 1
+            upload_to_s3(platform, package, timestamp)
+
+        if platform == 'macbrew':
+            update_brew(package, timestamp)
+
+        return 0