RequestProcessorResponseStatus RequestProcessor::ProcessGetStream(Envelope &request, vector<Envelope> &output)
{
{
::zippylog::request_processor::BeginProcessGetStream log;
LOG_MESSAGE(log, this->logger_sock);
}
protocol::request::GetStreamSegmentV1 *get = (protocol::request::GetStreamSegmentV1 *)request.GetMessage(0);
if (!get) {
::zippylog::request_processor::ReceiveInvalidGet log;
LOG_MESSAGE(log, this->logger_sock);
this->PopulateErrorResponse(
protocol::response::UNKNOWN_REQUEST_TYPE,
"error parsing get message... weird",
output
);
goto LOG_END;
}
if (!get->has_path()) {
::zippylog::request_processor::ReceiveInvalidGet log;
LOG_MESSAGE(log, this->logger_sock);
this->PopulateErrorResponse(
protocol::response::EMPTY_FIELD,
"required field 'path' is not set",
output
);
goto LOG_END;
}
if (!this->CheckPath(get->path(), output, true, true, true)) goto LOG_END;
if (!get->has_start_offset()) {
::zippylog::request_processor::ReceiveInvalidGet log;
LOG_MESSAGE(log, this->logger_sock);
this->PopulateErrorResponse(
protocol::response::EMPTY_FIELD,
"required field 'start_offset' is not set",
output
);
goto LOG_END;
}
{
InputStream *stream = this->store->GetInputStream(get->path());
if (!stream) {
// we've already verified the stream exists, so there are one of two possibilities:
// 1) it was deleted between then and now
// 2) error fetching stream
// @todo react accordingly
::zippylog::request_processor::GetInvalidStream log;
LOG_MESSAGE(log, this->logger_sock);
this->PopulateErrorResponse(
protocol::response::PATH_NOT_FOUND,
"requested stream could not be found",
output
);
goto LOG_END;
}
uint64 start_offset = get->start_offset();
if (start_offset && !stream->SetAbsoluteOffset(start_offset)) {
throw Exception("TODO handle error setting offset properly");
}
// determine how much to fetch
uint32 bytes_left = this->get_stream_max_bytes;
uint32 envelopes_left = this->get_stream_max_envelopes;
// client can lower server default if it wants
if (get->has_max_response_bytes() && get->max_response_bytes() < bytes_left) {
bytes_left = get->max_response_bytes();
}
if (get->has_max_response_envelopes() && get->max_response_envelopes() < envelopes_left) {
envelopes_left = get->max_response_envelopes();
}
zippylog::Envelope m = zippylog::Envelope();
uint32 envelope_size = stream->NextEnvelopeSize();
::zippylog::Envelope env;
// could not find envelope in stream at offset
if (!envelope_size || !stream->ReadEnvelope(env, envelope_size)) {
::zippylog::request_processor::GetInvalidOffset log;
LOG_MESSAGE(log, this->logger_sock);
// @todo need better error code
this->PopulateErrorResponse(
protocol::response::INVALID_STREAM_OFFSET,
"no envelopes found at requested stream offset",
output
);
goto LOG_END;
}
// we must have an envelope, so start the send sequence
{
Envelope start_envelope;
protocol::response::StreamSegmentStartV1 segment_start;
segment_start.set_path(get->path());
segment_start.set_offset(get->start_offset());
segment_start.add_to_envelope(start_envelope);
// copy request tags to response for client association
if (request.TagSize() >= 0) {
for (int i = 0; i < request.TagSize(); i++) {
start_envelope.AddTag(request.GetTag(i));
}
}
output.push_back(start_envelope);
}
output.push_back(env);
uint32 bytes_read = envelope_size;
uint32 envelopes_read = 1;
envelopes_left--;
if (bytes_read < bytes_left && envelopes_left) {
bytes_left -= envelope_size;
while (true) {
envelope_size = stream->NextEnvelopeSize();
if (!envelope_size) break;
// @todo we should be resilient and handle stream errors somehow
if (!stream->ReadEnvelope(env, envelope_size)) break;
output.push_back(env);
bytes_read += envelope_size;
envelopes_read++;
if (envelope_size > bytes_left) break;
if (envelopes_left-- == 1) break;
bytes_left -= envelope_size;
}
}
protocol::response::StreamSegmentEndV1 segment_end;
segment_end.set_envelopes_sent(envelopes_read);
segment_end.set_bytes_sent(bytes_read);
// @todo not all stores might share this concept of offsets
segment_end.set_offset(stream->CurrentEnvelopeOffset());
env = ::zippylog::Envelope();
segment_end.add_to_envelope(&env);
output.push_back(env);
}
LOG_END:
::zippylog::request_processor:: EndProcessGetStream logend;
LOG_MESSAGE(logend, this->logger_sock);
return AUTHORITATIVE;
}
