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import grpc
from .._protos.google.rpc import code_pb2
from .._protos.build.bazel.remote.execution.v2 import remote_execution_pb2, remote_execution_pb2_grpc
from .._protos.build.buildgrid import local_cas_pb2
from .._protos.buildstream.v2 import buildstream_pb2, buildstream_pb2_grpc
from .._remote import BaseRemote
from .._exceptions import CASRemoteError
# The default limit for gRPC messages is 4 MiB.
# Limit payload to 1 MiB to leave sufficient headroom for metadata.
_MAX_PAYLOAD_BYTES = 1024 * 1024
# How many digests to put in a single gRPC message.
# A 256-bit hash requires 64 bytes of space (hexadecimal encoding).
# 80 bytes provide sufficient space for hash, size, and protobuf overhead.
_MAX_DIGESTS = _MAX_PAYLOAD_BYTES / 80
class BlobNotFound(CASRemoteError):
def __init__(self, blob, msg):
self.blob = blob
super().__init__(msg)
# Represents a single remote CAS cache.
#
class CASRemote(BaseRemote):
def __init__(self, spec, cascache, **kwargs):
super().__init__(spec, **kwargs)
self.cascache = cascache
self.cas = None
self.ref_storage = None
self.batch_update_supported = None
self.batch_read_supported = None
self.capabilities = None
self.max_batch_total_size_bytes = None
self.local_cas_instance_name = None
# check_remote
# _configure_protocols():
#
# Configure remote-specific protocols. This method should *never*
# be called outside of init().
#
def _configure_protocols(self):
self.cas = remote_execution_pb2_grpc.ContentAddressableStorageStub(self.channel)
self.capabilities = remote_execution_pb2_grpc.CapabilitiesStub(self.channel)
self.ref_storage = buildstream_pb2_grpc.ReferenceStorageStub(self.channel)
# Figure out what batch sizes the server will accept, falling
# back to our _MAX_PAYLOAD_BYTES
self.max_batch_total_size_bytes = _MAX_PAYLOAD_BYTES
try:
request = remote_execution_pb2.GetCapabilitiesRequest()
if self.instance_name:
request.instance_name = self.instance_name
response = self.capabilities.GetCapabilities(request)
server_max_batch_total_size_bytes = response.cache_capabilities.max_batch_total_size_bytes
if 0 < server_max_batch_total_size_bytes < self.max_batch_total_size_bytes:
self.max_batch_total_size_bytes = server_max_batch_total_size_bytes
except grpc.RpcError as e:
# Simply use the defaults for servers that don't implement
# GetCapabilities()
if e.code() != grpc.StatusCode.UNIMPLEMENTED:
raise
# Check whether the server supports BatchReadBlobs()
self.batch_read_supported = self._check_support(
remote_execution_pb2.BatchReadBlobsRequest,
self.cas.BatchReadBlobs
)
# Check whether the server supports BatchUpdateBlobs()
self.batch_update_supported = self._check_support(
remote_execution_pb2.BatchUpdateBlobsRequest,
self.cas.BatchUpdateBlobs
)
local_cas = self.cascache._get_local_cas()
request = local_cas_pb2.GetInstanceNameForRemoteRequest()
request.url = self.spec.url
if self.spec.instance_name:
request.instance_name = self.spec.instance_name
if self.server_cert:
request.server_cert = self.server_cert
if self.client_key:
request.client_key = self.client_key
if self.client_cert:
request.client_cert = self.client_cert
response = local_cas.GetInstanceNameForRemote(request)
self.local_cas_instance_name = response.instance_name
# _check_support():
#
# Figure out if a remote server supports a given method based on
# grpc.StatusCode.UNIMPLEMENTED and grpc.StatusCode.PERMISSION_DENIED.
#
# Args:
# request_type (callable): The type of request to check.
# invoker (callable): The remote method that will be invoked.
#
# Returns:
# (bool) - Whether the request is supported.
#
def _check_support(self, request_type, invoker):
try:
request = request_type()
if self.instance_name:
request.instance_name = self.instance_name
invoker(request)
return True
except grpc.RpcError as e:
if not e.code() in (grpc.StatusCode.UNIMPLEMENTED, grpc.StatusCode.PERMISSION_DENIED):
raise
return False
# push_message():
#
# Push the given protobuf message to a remote.
#
# Args:
# message (Message): A protobuf message to push.
#
# Raises:
# (CASRemoteError): if there was an error
#
def push_message(self, message):
message_buffer = message.SerializeToString()
self.init()
return self.cascache.add_object(buffer=message_buffer, instance_name=self.local_cas_instance_name)
# Represents a batch of blobs queued for fetching.
#
class _CASBatchRead():
def __init__(self, remote):
self._remote = remote
self._requests = []
self._request = None
self._sent = False
def add(self, digest):
assert not self._sent
if not self._request or len(self._request.blob_digests) >= _MAX_DIGESTS:
self._request = local_cas_pb2.FetchMissingBlobsRequest()
self._request.instance_name = self._remote.local_cas_instance_name
self._requests.append(self._request)
request_digest = self._request.blob_digests.add()
request_digest.CopyFrom(digest)
def send(self, *, missing_blobs=None):
assert not self._sent
self._sent = True
if not self._requests:
return
local_cas = self._remote.cascache._get_local_cas()
for request in self._requests:
batch_response = local_cas.FetchMissingBlobs(request)
for response in batch_response.responses:
if response.status.code == code_pb2.NOT_FOUND:
if missing_blobs is None:
raise BlobNotFound(response.digest.hash, "Failed to download blob {}: {}".format(
response.digest.hash, response.status.code))
missing_blobs.append(response.digest)
if response.status.code != code_pb2.OK:
raise CASRemoteError("Failed to download blob {}: {}".format(
response.digest.hash, response.status.code))
if response.digest.size_bytes != len(response.data):
raise CASRemoteError("Failed to download blob {}: expected {} bytes, received {} bytes".format(
response.digest.hash, response.digest.size_bytes, len(response.data)))
# Represents a batch of blobs queued for upload.
#
class _CASBatchUpdate():
def __init__(self, remote):
self._remote = remote
self._requests = []
self._request = None
self._sent = False
def add(self, digest):
assert not self._sent
if not self._request or len(self._request.blob_digests) >= _MAX_DIGESTS:
self._request = local_cas_pb2.UploadMissingBlobsRequest()
self._request.instance_name = self._remote.local_cas_instance_name
self._requests.append(self._request)
request_digest = self._request.blob_digests.add()
request_digest.CopyFrom(digest)
def send(self):
assert not self._sent
self._sent = True
if not self._requests:
return
local_cas = self._remote.cascache._get_local_cas()
for request in self._requests:
batch_response = local_cas.UploadMissingBlobs(request)
for response in batch_response.responses:
if response.status.code != code_pb2.OK:
if response.status.code == code_pb2.RESOURCE_EXHAUSTED:
reason = "cache-too-full"
else:
reason = None
raise CASRemoteError("Failed to upload blob {}: {}".format(
response.digest.hash, response.status.code), reason=reason)
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