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// Copyright 2021 The Pigweed Authors
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
#include "pw_log_rpc/rpc_log_drain.h"
#include <mutex>
#include "pw_assert/check.h"
#include "pw_log/log.h"
#include "pw_string/string_builder.h"
namespace pw::log_rpc {
namespace {
// When encoding LogEntry in LogEntries, there are kLogEntryEncodeFrameSize
// bytes added to the encoded LogEntry.
constexpr size_t kLogEntryEncodeFrameSize =
protobuf::SizeOfFieldKey(1) // LogEntry
+ protobuf::kMaxSizeOfLength;
// Creates an encoded drop message on the provided buffer.
Result<ConstByteSpan> CreateEncodedDropMessage(
uint32_t drop_count, ByteSpan encoded_drop_message_buffer) {
StringBuffer<RpcLogDrain::kMaxDropMessageSize> message;
message.Format(RpcLogDrain::kDropMessageFormatString,
static_cast<unsigned int>(drop_count));
// Encode message in protobuf.
log::LogEntry::MemoryEncoder encoder(encoded_drop_message_buffer);
encoder.WriteMessage(std::as_bytes(std::span(std::string_view(message))));
encoder.WriteLineLevel(PW_LOG_LEVEL_WARN & PW_LOG_LEVEL_BITMASK);
PW_TRY(encoder.status());
return ConstByteSpan(encoder);
}
} // namespace
Status RpcLogDrain::Open(rpc::RawServerWriter& writer) {
if (!writer.open()) {
return Status::FailedPrecondition();
}
std::lock_guard lock(mutex_);
if (server_writer_.open()) {
return Status::AlreadyExists();
}
server_writer_ = std::move(writer);
return OkStatus();
}
Status RpcLogDrain::Flush() {
PW_CHECK_NOTNULL(multisink_);
LogDrainState log_sink_state = LogDrainState::kMoreEntriesRemaining;
std::lock_guard lock(mutex_);
do {
if (!server_writer_.open()) {
return Status::Unavailable();
}
log::LogEntries::MemoryEncoder encoder(server_writer_.PayloadBuffer());
uint32_t packed_entry_count = 0;
log_sink_state = EncodeOutgoingPacket(encoder, packed_entry_count);
if (const Status status = server_writer_.Write(encoder); !status.ok()) {
committed_entry_drop_count_ += packed_entry_count;
if (error_handling_ == LogDrainErrorHandling::kCloseStreamOnWriterError) {
server_writer_.Finish().IgnoreError();
return Status::Aborted();
}
}
} while (log_sink_state == LogDrainState::kMoreEntriesRemaining);
return OkStatus();
}
RpcLogDrain::LogDrainState RpcLogDrain::EncodeOutgoingPacket(
log::LogEntries::MemoryEncoder& encoder, uint32_t packed_entry_count_out) {
const size_t total_buffer_size = encoder.ConservativeWriteLimit();
do {
// Get entry and drop count from drain.
uint32_t drop_count = 0;
Result<multisink::MultiSink::Drain::PeekedEntry> possible_entry =
PeekEntry(log_entry_buffer_, drop_count);
if (possible_entry.status().IsResourceExhausted() ||
possible_entry.status().IsDataLoss()) {
continue;
}
// Report drop count if messages were dropped.
if (committed_entry_drop_count_ > 0 || drop_count > 0) {
// Reuse the log_entry_buffer_ to send a drop message.
const Result<ConstByteSpan> drop_message_result =
CreateEncodedDropMessage(committed_entry_drop_count_ + drop_count,
log_entry_buffer_);
// Add encoded drop messsage if fits in buffer.
if (drop_message_result.ok() &&
drop_message_result.value().size() + kLogEntryEncodeFrameSize <
encoder.ConservativeWriteLimit()) {
PW_CHECK_OK(encoder.WriteBytes(
static_cast<uint32_t>(log::LogEntries::Fields::ENTRIES),
drop_message_result.value()));
committed_entry_drop_count_ = 0;
}
if (possible_entry.ok()) {
PW_CHECK_OK(PeekEntry(log_entry_buffer_, drop_count).status());
}
}
if (possible_entry.status().IsOutOfRange()) {
return LogDrainState::kCaughtUp; // There are no more entries.
}
// At this point all expected error modes have been handled.
PW_CHECK_OK(possible_entry.status());
// Check if the entry fits in encoder buffer.
const size_t encoded_entry_size =
possible_entry.value().entry().size() + kLogEntryEncodeFrameSize;
if (encoded_entry_size + kLogEntryEncodeFrameSize > total_buffer_size) {
// Entry is larger than the entire available buffer.
++committed_entry_drop_count_;
PW_CHECK_OK(PopEntry(possible_entry.value()));
continue;
} else if (encoded_entry_size > encoder.ConservativeWriteLimit()) {
// Entry does not fit in the partially filled encoder buffer. Notify the
// caller there are more entries to send.
return LogDrainState::kMoreEntriesRemaining;
}
// Encode log entry and remove it from multisink.
PW_CHECK_OK(encoder.WriteBytes(
static_cast<uint32_t>(log::LogEntries::Fields::ENTRIES),
possible_entry.value().entry()));
PW_CHECK_OK(PopEntry(possible_entry.value()));
++packed_entry_count_out;
} while (true);
}
Status RpcLogDrain::Close() {
std::lock_guard lock(mutex_);
return server_writer_.Finish();
}
} // namespace pw::log_rpc
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