[fuchsia] Remove legacy Fuchsia SDK cleanup & tidy up logging.

Remove logic from update-sdk.py for cleaning up the Fuchsia SDK from the
old download path, since it has been ~years since we migrated.

Replace all use of print() with logging.info() and set default logging
level to logging.INFO.

Bug: 1050703
Change-Id: I816d68988506fd6d5c7b98514048b41c34ab550f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2056809Reviewed-by: Fabrice de Gans-Riberi <fdegans@chromium.org>
Commit-Queue: Fabrice de Gans-Riberi <fdegans@chromium.org>
Auto-Submit: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#741514}

build/fuchsia/update_sdk.py

@@ -6,8 +6,6 @@
 """Updates the Fuchsia SDK to the given revision. Should be used in a 'hooks_os'
 entry so that it only runs when .gclient's target_os includes 'fuchsia'."""
 
-from __future__ import print_function
-
 import argparse
 import itertools
 import logging
@@ -17,7 +15,6 @@ import shutil
 import subprocess
 import sys
 import tarfile
-import tempfile
 
 from common import GetHostOsFromPlatform, GetHostArchFromPlatform, \
                    DIR_SOURCE_ROOT, SDK_ROOT, IMAGES_ROOT
@@ -64,7 +61,7 @@ def GetSdkHashForPlatform():
 
   # If both files are empty, return an error.
   if not sdk_hash and not extra_sdk_hash:
-    print(
+    logging.error(
         'No SHA1 found in {} or {}'.format(hash_file, extra_hash_file),
         file=sys.stderr)
     return 1
@@ -87,19 +84,6 @@ def EnsureDirExists(path):
     os.makedirs(path)
 
 
-# Removes legacy SDK if it's detected.
-def CleanupLegacySDK():
-  legacy_sdk_root = os.path.join(DIR_SOURCE_ROOT, 'third_party', 'fuchsia-sdk')
-  hash_file = os.path.join(legacy_sdk_root, '.hash')
-  if os.path.exists(hash_file):
-    print('Removing legacy SDK.')
-    for d in SDK_SUBDIRS:
-      to_remove = os.path.join(legacy_sdk_root, d)
-      if os.path.isdir(to_remove):
-        shutil.rmtree(to_remove)
-    os.remove(hash_file)
-
-
 # Updates the modification timestamps of |path| and its contents to the
 # current time.
 def UpdateTimestampsRecursive():
@@ -157,7 +141,8 @@ def DownloadSdkBootImages(sdk_hash, boot_image_names):
     if os.path.exists(image_output_dir):
       continue
 
-    print('Downloading Fuchsia boot images for %s.%s...' % (device_type, arch))
+    logging.info(
+        'Downloading Fuchsia boot images for %s.%s...' % (device_type, arch))
     images_tarball_url = \
         'gs://fuchsia/development/{sdk_hash}/images/'\
         '{device_type}-{arch}.tgz'.format(
@@ -177,7 +162,7 @@ def main():
          'If omitted, no boot images will be downloaded.')
   args = parser.parse_args()
 
-  logging.basicConfig(level=logging.DEBUG if args.verbose else logging.WARNING)
+  logging.basicConfig(level=logging.DEBUG if args.verbose else logging.INFO)
 
   # Quietly exit if there's no SDK support for this platform.
   try:
@@ -185,45 +170,25 @@ def main():
   except:
     return 0
 
-  # Previously SDK was unpacked in //third_party/fuchsia-sdk instead of
-  # //third_party/fuchsia-sdk/sdk . Remove the old files if they are still
-  # there.
-  CleanupLegacySDK()
-
   sdk_hash = GetSdkHashForPlatform()
   if not sdk_hash:
     return 1
 
   hash_filename = os.path.join(SDK_ROOT, '.hash')
-  if os.path.exists(hash_filename):
-    with open(hash_filename, 'r') as f:
-      if f.read().strip() == sdk_hash:
-        # Ensure that the boot images are downloaded for this SDK.
-        # If the developer opted into downloading hardware boot images in their
-        # .gclient file, then only the hardware boot images will be downloaded.
-        DownloadSdkBootImages(sdk_hash, args.boot_images)
-
-        # Nothing to do. Generate sdk/BUILD.gn anyway, in case the conversion
-        # script changed.
-        logging.info("Generating sdk/BUILD.gn")
-        cmd = [os.path.join(SDK_ROOT, '..', 'gen_build_defs.py')]
-        logging.debug("Running '%s'", " ".join(cmd))
-        subprocess.check_call(cmd)
-        return 0
-
-  print('Downloading SDK %s...' % sdk_hash)
+  if ((not os.path.exists(hash_filename))
+      or (open(hash_filename, 'r').read().strip() != sdk_hash)):
+    logging.info('Downloading SDK %s...' % sdk_hash)
 
     if os.path.isdir(SDK_ROOT):
       shutil.rmtree(SDK_ROOT)
 
-  fd, tmp = tempfile.mkstemp()
-  os.close(fd)
-
     EnsureDirExists(SDK_ROOT)
     DownloadAndUnpackFromCloudStorage(GetSdkBucketForPlatform() + sdk_hash,
                                       SDK_ROOT)
 
-  # Generate sdk/BUILD.gn.
+  # Always re-generate sdk/BUILD.gn, even if the SDK hash has not changed,
+  # in case the gen_build_defs.py script changed.
+  logging.info("Generating sdk/BUILD.gn")
   cmd = [os.path.join(SDK_ROOT, '..', 'gen_build_defs.py')]
   logging.debug("Running '%s'", " ".join(cmd))
   subprocess.check_call(cmd)
@@ -234,6 +199,9 @@ def main():
   os.mkdir(IMAGES_ROOT)
 
   try:
+    # Ensure that the boot images are downloaded for this SDK.
+    # If the developer opted into downloading hardware boot images in their
+    # .gclient file, then only the hardware boot images will be downloaded.
     DownloadSdkBootImages(sdk_hash, args.boot_images)
   except subprocess.CalledProcessError as e:
     logging.error((