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.)

etc/ci/buildbot_steps.yml

@@ -38,8 +38,8 @@ mac-nightly:
   - ./mach clean-nightlies --keep 3 --force
   - ./mach build --release
   - ./mach package --release
-  - ./etc/ci/upload_nightly.sh mac
-  - ./etc/ci/upload_nightly.sh macbrew
+  - ./mach upload-nightly mac
+  - ./mach upload-nightly macbrew
 
 linux-rel-intermittent:
   - ./mach clean-nightlies --keep 3 --force
@@ -89,7 +89,7 @@ linux-nightly:
   - ./mach clean-nightlies --keep 3 --force
   - ./mach build --release
   - ./mach package --release
-  - ./etc/ci/upload_nightly.sh linux
+  - ./mach upload-nightly linux
 
 android:
   - ./mach clean-nightlies --keep 3 --force
@@ -103,7 +103,7 @@ android-nightly:
   - ./mach clean-nightlies --keep 3 --force
   - env SERVO_RUSTC_LLVM_ASSERTIONS=1 ./mach build --android --release
   - env SERVO_RUSTC_LLVM_ASSERTIONS=1 ANDROID_SDK=/home/servo/android/sdk/r25.2.3 ./mach package --android --release
-  - ./etc/ci/upload_nightly.sh android
+  - ./mach upload-nightly android
 
 arm32:
   - ./mach clean-nightlies --keep 3 --force
@@ -128,4 +128,4 @@ windows-msvc-nightly:
   - mach.bat clean-nightlies --keep 3 --force
   - mach.bat build --release
   - mach.bat package --release
-  - bash -l ./etc/ci/upload_nightly.sh windows-msvc
+  - mach.bat upload-nightly windows-msvc

etc/ci/upload_nightly.sh

@@ -1,113 +0,0 @@
-#!/usr/bin/env bash
-
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-set -o errexit
-set -o nounset
-set -o pipefail
-shopt -s failglob
-
-
-usage() {
-    printf \
-        "usage: %s android|linux|mac|macbrew|windows-msvc\n" \
-        "${0}"
-}
-
-
-upload() {
-    local nightly_filename
-    nightly_filename="${4}-$(basename "${2}")"
-    local -r nightly_upload_dir="s3://servo-builds/nightly/${1}"
-    local -r package_upload_path="${nightly_upload_dir}/${nightly_filename}"
-    s3cmd --mime-type="application/octet-stream" \
-          put "${2}" "${package_upload_path}"
-    s3cmd cp "${package_upload_path}" "${nightly_upload_dir}/servo-latest.${3}"
-}
-
-update_brew() {
-  echo "Updating brew formula"
-
-  local package_url sha version script_dir tmp_dir nightly_filename
-
-  nightly_filename="${2}-$(basename "${1}")"
-  package_url="https://download.servo.org/nightly/macbrew/${nightly_filename}"
-  sha="$(shasum -a 256 "${1}" | sed -e 's/ .*//')"
-
-  # This will transform a timestamp (2016-12-13T08-01-10Z for example)
-  # into a valid brew version number (2016.12.13).
-  version="$(echo "${2}" | \
-    sed -n 's/\([0-9]\{4\}\)-\([0-9]\{2\}\)-\([0-9]\{2\}\).*/\1.\2.\3/p')"
-
-  script_dir="${PWD}/$(dirname "${0}")"
-  tmp_dir="$(mktemp -d -t homebrew-servo.XXXXX)"
-
-  git -C "${tmp_dir}" clone https://github.com/servo/homebrew-servo.git .
-
-  # Not using "/" as it's used in PACKAGEURL
-  sed "s|PACKAGEURL|${package_url}|g
-       s|SHA|${sha}|g
-       s|VERSION|${version}|g" \
-       < "${script_dir}/servo-binary-formula.rb.in" \
-       > "${tmp_dir}/Formula/servo-bin.rb"
-
-  git -C "${tmp_dir}" add ./Formula/servo-bin.rb
-  git -C "${tmp_dir}" \
-      -c user.name="Tom Servo" \
-      -c user.email="servo@servo.org" \
-      commit \
-      --message="Version bump: ${version}"
-
-  git -C "${tmp_dir}" push -qf \
-      "https://${GITHUB_HOMEBREW_TOKEN}@github.com/servo/homebrew-servo.git" \
-      master >/dev/null 2>&1
-
-  rm -rf "${tmp_dir}"
-}
-
-main() {
-    if (( "${#}" != 1 )); then
-        usage >&2
-        return 1
-    fi
-
-    local platform package extension nightly_timestamp
-    platform="${1}"
-    nightly_timestamp="$(date -u +"%Y-%m-%dT%H-%M-%SZ")"
-
-    if [[ "${platform}" == "android" ]]; then
-        extension=apk
-        package=target/arm-linux-androideabi/release/*."${extension}"
-    elif [[ "${platform}" == "linux" ]]; then
-        extension=tar.gz
-        package=target/release/*."${extension}"
-    elif [[ "${platform}" == "mac" ]]; then
-        extension=dmg
-        package=target/release/*."${extension}"
-    elif [[ "${platform}" == "macbrew" ]]; then
-        extension=tar.gz
-        package=target/release/brew/*."${extension}"
-    elif [[ "${platform}" == "windows-msvc" ]]; then
-        extension=msi
-        package=target/release/msi/*.msi
-        upload "${platform}" ${package} "${extension}" "${nightly_timestamp}"
-        extension=zip
-        package=target/release/msi/*.zip
-    else
-        usage >&2
-        return 1
-    fi
-
-    # Lack of quotes on package allows glob expansion
-    # Note that this is not robust in the case of embedded spaces
-    # TODO(aneeshusa): make this glob robust using e.g. arrays or Python
-    upload "${platform}" ${package} "${extension}" "${nightly_timestamp}"
-
-    if [[ "${platform}" == "macbrew" ]]; then
-      update_brew ${package} "${nightly_timestamp}"
-    fi
-}
-
-main "${@}"