quay/endpoints/v2/blob.py

import logging
import re

from flask import url_for, request, redirect, Response, abort as flask_abort

import resumablehashlib

from app import storage, app, get_app_url
from auth.registry_jwt_auth import process_registry_jwt_auth
from data import database
from data.interfaces.v2 import pre_oci_model as model
from digest import digest_tools
from endpoints.common import parse_repository_name
from endpoints.v2 import v2_bp, require_repo_read, require_repo_write, get_input_stream
from endpoints.v2.errors import (BlobUnknown, BlobUploadInvalid, BlobUploadUnknown, Unsupported,
                                 NameUnknown)
from endpoints.decorators import anon_protect
from util.cache import cache_control
from util.registry.filelike import wrap_with_handler, StreamSlice
from util.registry.gzipstream import calculate_size_handler
from util.registry.torrent import PieceHasher


logger = logging.getLogger(__name__)


BASE_BLOB_ROUTE = '/<repopath:repository>/blobs/<regex("{0}"):digest>'
BLOB_DIGEST_ROUTE = BASE_BLOB_ROUTE.format(digest_tools.DIGEST_PATTERN)
RANGE_HEADER_REGEX = re.compile(r'^bytes=([0-9]+)-([0-9]+)$')
BLOB_CONTENT_TYPE = 'application/octet-stream'


class _InvalidRangeHeader(Exception):
  pass


@v2_bp.route(BLOB_DIGEST_ROUTE, methods=['HEAD'])
@parse_repository_name()
@process_registry_jwt_auth(scopes=['pull'])
@require_repo_read
@anon_protect
@cache_control(max_age=31436000)
def check_blob_exists(namespace_name, repo_name, digest):
  # Find the blob.
  blob = model.get_blob_by_digest(namespace_name, repo_name, digest)
  if blob is None:
    raise BlobUnknown()

  # Build the response headers.
  headers = {
    'Docker-Content-Digest': digest,
    'Content-Length': blob.size,
    'Content-Type': BLOB_CONTENT_TYPE,
  }

  # If our storage supports range requests, let the client know.
  if storage.get_supports_resumable_downloads(blob.locations):
    headers['Accept-Ranges'] = 'bytes'

  # Write the response to the client.
  return Response(headers=headers)


@v2_bp.route(BLOB_DIGEST_ROUTE, methods=['GET'])
@parse_repository_name()
@process_registry_jwt_auth(scopes=['pull'])
@require_repo_read
@anon_protect
@cache_control(max_age=31536000)
def download_blob(namespace_name, repo_name, digest):
  # Find the blob.
  blob = model.get_blob_by_digest(namespace_name, repo_name, digest)
  if blob is None:
    raise BlobUnknown()

  # Build the response headers.
  headers = {'Docker-Content-Digest': digest}

  # If our storage supports range requests, let the client know.
  if storage.get_supports_resumable_downloads(blob.locations):
    headers['Accept-Ranges'] = 'bytes'

  # Find the storage path for the blob.
  path = model.get_blob_path(blob)

  # Short-circuit by redirecting if the storage supports it.
  logger.debug('Looking up the direct download URL for path: %s', path)
  direct_download_url = storage.get_direct_download_url(blob.locations, path)
  if direct_download_url:
    logger.debug('Returning direct download URL')
    resp = redirect(direct_download_url)
    resp.headers.extend(headers)
    return resp

  # Close the database connection before we stream the download.
  logger.debug('Closing database connection before streaming layer data')
  with database.CloseForLongOperation(app.config):
    # Stream the response to the client.
    return Response(
      storage.stream_read(blob.locations, path),
      headers=headers.update({
        'Content-Length': blob.size,
        'Content-Type': BLOB_CONTENT_TYPE,
      }),
    )



@v2_bp.route('/<repopath:repository>/blobs/uploads/', methods=['POST'])
@parse_repository_name()
@process_registry_jwt_auth(scopes=['pull', 'push'])
@require_repo_write
@anon_protect
def start_blob_upload(namespace_name, repo_name):
  # Begin the blob upload process in the database and storage.
  location_name = storage.preferred_locations[0]
  new_upload_uuid, upload_metadata = storage.initiate_chunked_upload(location_name)
  repository_exists = model.create_blob_upload(namespace_name, repo_name, new_upload_uuid,
                                               location_name, upload_metadata)
  if not repository_exists:
    raise NameUnknown()

  digest = request.args.get('digest', None)
  if digest is None:
    # Short-circuit because the user will send the blob data in another request.
    return Response(
      status=202,
      headers={
        'Docker-Upload-UUID': new_upload_uuid,
        'Range': _render_range(0),
        'Location': get_app_url() + url_for('v2.upload_chunk',
                                            repository='%s/%s' % (namespace_name, repo_name),
                                            upload_uuid=new_upload_uuid)
      },
    )

  # The user plans to send us the entire body right now.
  # Find the upload.
  blob_upload = model.blob_upload_by_uuid(namespace_name, repo_name, new_upload_uuid)
  if blob_upload is None:
    raise BlobUploadUnknown()

  # Upload the chunk to storage while calculating some metadata and updating
  # the upload state.
  updated_blob_upload = _upload_chunk(blob_upload, request.headers.get('range'))
  if updated_blob_upload is None:
    _abort_range_not_satisfiable(blob_upload.byte_count, new_upload_uuid)

  # Save the upload state to the database.
  model.update_blob_upload(updated_blob_upload)

  # Finalize the upload process in the database and storage.
  _finish_upload(namespace_name, repo_name, updated_blob_upload, digest)

  # Write the response to the client.
  return Response(
    status=201,
    headers={
      'Docker-Content-Digest': digest,
      'Location': get_app_url() + url_for('v2.download_blob',
                                          repository='%s/%s' % (namespace_name, repo_name),
                                          digest=digest),
    },
  )


@v2_bp.route('/<repopath:repository>/blobs/uploads/<upload_uuid>', methods=['GET'])
@parse_repository_name()
@process_registry_jwt_auth(scopes=['pull'])
@require_repo_write
@anon_protect
def fetch_existing_upload(namespace_name, repo_name, upload_uuid):
  blob_upload = model.blob_upload_by_uuid(namespace_name, repo_name, upload_uuid)
  if blob_upload is None:
    raise BlobUploadUnknown()

  return Response(
    status=204,
    headers={
      'Docker-Upload-UUID': upload_uuid,
      'Range': _render_range(blob_upload.byte_count+1), # byte ranges are exclusive
    },
  )


@v2_bp.route('/<repopath:repository>/blobs/uploads/<upload_uuid>', methods=['PATCH'])
@parse_repository_name()
@process_registry_jwt_auth(scopes=['pull', 'push'])
@require_repo_write
@anon_protect
def upload_chunk(namespace_name, repo_name, upload_uuid):
  # Find the upload.
  blob_upload = model.blob_upload_by_uuid(namespace_name, repo_name, upload_uuid)
  if blob_upload is None:
    raise BlobUploadUnknown()

  # Upload the chunk to storage while calculating some metadata and updating
  # the upload state.
  updated_blob_upload = _upload_chunk(blob_upload, request.headers.get('range'))
  if updated_blob_upload is None:
    _abort_range_not_satisfiable(blob_upload.byte_count, upload_uuid)

  # Save the upload state to the database.
  model.update_blob_upload(updated_blob_upload)

  # Write the response to the client.
  return Response(
    status=204,
    headers={
      'Location': _current_request_url(),
      'Range': _render_range(updated_blob_upload.byte_count, with_bytes_prefix=False),
      'Docker-Upload-UUID': upload_uuid,
    },
  )


@v2_bp.route('/<repopath:repository>/blobs/uploads/<upload_uuid>', methods=['PUT'])
@parse_repository_name()
@process_registry_jwt_auth(scopes=['pull', 'push'])
@require_repo_write
@anon_protect
def monolithic_upload_or_last_chunk(namespace_name, repo_name, upload_uuid):
  # Ensure the digest is present before proceeding.
  digest = request.args.get('digest', None)
  if digest is None:
    raise BlobUploadInvalid(detail={'reason': 'Missing digest arg on monolithic upload'})

  # Find the upload.
  blob_upload = model.blob_upload_by_uuid(namespace_name, repo_name, upload_uuid)
  if blob_upload is None:
    raise BlobUploadUnknown()

  # Upload the chunk to storage while calculating some metadata and updating
  # the upload state.
  updated_blob_upload = _upload_chunk(blob_upload, request.headers.get('range'))
  if updated_blob_upload is None:
    _abort_range_not_satisfiable(blob_upload.byte_count, upload_uuid)

  # Finalize the upload process in the database and storage.
  _finish_upload(namespace_name, repo_name, updated_blob_upload, digest)

  # Write the response to the client.
  return Response(
    status=201,
    headers={
      'Docker-Content-Digest': digest,
      'Location': get_app_url() + url_for('v2.download_blob',
                                          repository='%s/%s' % (namespace_name, repo_name),
                                          digest=digest),
    }
  )


@v2_bp.route('/<repopath:repository>/blobs/uploads/<upload_uuid>', methods=['DELETE'])
@parse_repository_name()
@process_registry_jwt_auth(scopes=['pull', 'push'])
@require_repo_write
@anon_protect
def cancel_upload(namespace_name, repo_name, upload_uuid):
  blob_upload = model.blob_upload_by_uuid(namespace_name, repo_name, upload_uuid)
  if blob_upload is None:
    raise BlobUploadUnknown()

  # We delete the record for the upload first, since if the partial upload in
  # storage fails to delete, it doesn't break anything.
  model.delete_blob_upload(namespace_name, repo_name, upload_uuid)
  storage.cancel_chunked_upload({blob_upload.location_name}, blob_upload.uuid,
                                blob_upload.storage_metadata)

  return Response(status=204)


@v2_bp.route('/<repopath:repository>/blobs/<digest>', methods=['DELETE'])
@parse_repository_name()
@process_registry_jwt_auth(scopes=['pull', 'push'])
@require_repo_write
@anon_protect
def delete_digest(namespace_name, repo_name, upload_uuid):
  # We do not support deleting arbitrary digests, as they break repo images.
  raise Unsupported()


def _render_range(num_uploaded_bytes, with_bytes_prefix=True):
  """
  Returns a string formatted to be used in the Range header.
  """
  return '{0}0-{1}'.format('bytes=' if with_bytes_prefix else '', num_uploaded_bytes - 1)


def _current_request_url():
  return '{0}{1}{2}'.format(get_app_url(), request.script_root, request.path)


def _abort_range_not_satisfiable(valid_end, upload_uuid):
  """
  Writes a failure response for scenarios where the registry cannot function
  with the provided range.

  TODO(jzelinskie): Unify this with the V2RegistryException class.
  """
  flask_abort(Response(status=416, headers={'Location': _current_request_url(),
                                            'Range': '0-{0}'.format(valid_end),
                                            'Docker-Upload-UUID': upload_uuid}))


def _parse_range_header(range_header_text):
  """
  Parses the range header.

  Returns a tuple of the start offset and the length.
  If the parse fails, raises _InvalidRangeHeader.
  """
  found = RANGE_HEADER_REGEX.match(range_header_text)
  if found is None:
    raise _InvalidRangeHeader()

  start = int(found.group(1))
  length = int(found.group(2)) - start

  if length <= 0:
    raise _InvalidRangeHeader()

  return (start, length)


def _start_offset_and_length(range_header):
  """
  Returns a tuple of the start offset and the length.
  If the range header doesn't exist, defaults to (0, -1).
  If parsing fails, returns (None, None).
  """
  start_offset, length = 0, -1
  if range_header is not None:
    try:
      start_offset, length = _parse_range_header(range_header)
    except _InvalidRangeHeader:
      return None, None

  return start_offset, length


def _upload_chunk(blob_upload, range_header):
  """
  Calculates metadata while uploading a chunk to storage.

  Returns a BlobUpload object or None if there was a failure.
  """
  # Get the offset and length of the current chunk.
  start_offset, length = _start_offset_and_length(range_header)
  if blob_upload is None or None in {start_offset, length}:
    logger.error('Invalid arguments provided to _upload_chunk')
    return None

  if start_offset > 0 and start_offset > blob_upload.byte_count:
    logger.error('start_offset provided to _upload_chunk greater than blob.upload.byte_count')
    return None

  location_set = {blob_upload.location_name}

  upload_error = None
  with database.CloseForLongOperation(app.config):
    input_fp = get_input_stream(request)

    if start_offset > 0 and start_offset < blob_upload.byte_count:
      # Skip the bytes which were received on a previous push, which are already stored and
      # included in the sha calculation
      overlap_size = blob_upload.byte_count - start_offset
      input_fp = StreamSlice(input_fp, overlap_size)

      # Update our upload bounds to reflect the skipped portion of the overlap
      start_offset = blob_upload.byte_count
      length = max(length - overlap_size, 0)

    # We use this to escape early in case we have already processed all of the bytes the user
    # wants to upload
    if length == 0:
      return blob_upload

    input_fp = wrap_with_handler(input_fp, blob_upload.sha_state.update)

    # Add a hasher for calculating SHA1s for torrents if this is the first chunk and/or we have
    # already calculated hash data for the previous chunk(s).
    piece_hasher = None
    if blob_upload.chunk_count == 0 or blob_upload.piece_sha_state:
      initial_sha1_value = blob_upload.piece_sha_state or resumablehashlib.sha1()
      initial_sha1_pieces_value = blob_upload.piece_hashes or ''

      piece_hasher = PieceHasher(app.config['BITTORRENT_PIECE_SIZE'], start_offset,
                                 initial_sha1_pieces_value, initial_sha1_value)

      input_fp = wrap_with_handler(input_fp, piece_hasher.update)

    # If this is the first chunk and we're starting at the 0 offset, add a handler to gunzip the
    # stream so we can determine the uncompressed size. We'll throw out this data if another chunk
    # comes in, but in the common case the docker client only sends one chunk.
    size_info = None
    if start_offset == 0 and blob_upload.chunk_count == 0:
      size_info, fn = calculate_size_handler()
      input_fp = wrap_with_handler(input_fp, fn)

    length_written, new_metadata, upload_error = storage.stream_upload_chunk(
      location_set,
      blob_upload.uuid,
      start_offset,
      length,
      input_fp,
      blob_upload.storage_metadata,
      content_type=BLOB_CONTENT_TYPE,
    )

    if upload_error is not None:
      logger.error('storage.stream_upload_chunk returned error %s', upload_error)
      return None

  # If we determined an uncompressed size and this is the first chunk, add it to the blob.
  # Otherwise, we clear the size from the blob as it was uploaded in multiple chunks.
  if size_info is not None and blob_upload.chunk_count == 0 and size_info.is_valid:
    blob_upload.uncompressed_byte_count = size_info.uncompressed_size
  elif length_written > 0:
    # Otherwise, if we wrote some bytes and the above conditions were not met, then we don't
    # know the uncompressed size.
    blob_upload.uncompressed_byte_count = None

  if piece_hasher is not None:
    blob_upload.piece_hashes = piece_hasher.piece_hashes
    blob_upload.piece_sha_state = piece_hasher.hash_fragment

  blob_upload.storage_metadata = new_metadata
  blob_upload.byte_count += length_written
  blob_upload.chunk_count += 1
  return blob_upload


def _validate_digest(blob_upload, expected_digest):
  """
  Verifies that the digest's SHA matches that of the uploaded data.
  """
  computed_digest = digest_tools.sha256_digest_from_hashlib(blob_upload.sha_state)
  if not digest_tools.digests_equal(computed_digest, expected_digest):
    logger.error('Digest mismatch for upload %s: Expected digest %s, found digest %s',
                 blob_upload.uuid, expected_digest, computed_digest)
    raise BlobUploadInvalid(detail={'reason': 'Digest mismatch on uploaded blob'})


def _finalize_blob_storage(blob_upload, expected_digest):
  """
  When an upload is successful, this ends the uploading process from the
  storage's perspective.

  Returns True if the blob already existed.
  """
  final_blob_location = digest_tools.content_path(expected_digest)

  # Move the storage into place, or if this was a re-upload, cancel it
  with database.CloseForLongOperation(app.config):
    already_existed = storage.exists({blob_upload.location_name}, final_blob_location)
    if already_existed:
      # It already existed, clean up our upload which served as proof that the
      # uploader had the blob.
      storage.cancel_chunked_upload({blob_upload.location_name}, blob_upload.uuid,
                                    blob_upload.storage_metadata)

    else:
      # We were the first ones to upload this image (at least to this location)
      # Let's copy it into place
      storage.complete_chunked_upload({blob_upload.location_name}, blob_upload.uuid,
                                      final_blob_location, blob_upload.storage_metadata)
  return already_existed


def _finalize_blob_database(namespace_name, repo_name, blob_upload, digest, already_existed):
  """
  When an upload is successful, this ends the uploading process from the
  database's perspective.
  """
  # Create the blob and temporarily tag it.
  blob_storage = model.create_blob_and_temp_tag(
    namespace_name,
    repo_name,
    digest,
    blob_upload,
    app.config['PUSH_TEMP_TAG_EXPIRATION_SEC'],
  )

  # If it doesn't already exist, create the BitTorrent pieces for the blob.
  if blob_upload.piece_sha_state is not None and not already_existed:
    piece_bytes = blob_upload.piece_hashes + blob_upload.piece_sha_state.digest()
    model.save_bittorrent_pieces(blob_storage, app.config['BITTORRENT_PIECE_SIZE'], piece_bytes)

  # Delete the blob upload.
  model.delete_blob_upload(namespace_name, repo_name, blob_upload.uuid)


def _finish_upload(namespace_name, repo_name, blob_upload, digest):
  """
  When an upload is successful, this ends the uploading process.
  """
  _validate_digest(blob_upload, digest)
  _finalize_blob_database(
    namespace_name,
    repo_name,
    blob_upload,
    digest,
    _finalize_blob_storage(blob_upload, digest),
  )