add support for replaying log messages
For example, this allows reproducing logged but hard to physically
reproduce problems to control loops with more logging to help debug the
problem, and then verifying that it does something different under the
same conditions.
Change-Id: I1e55e7a7c0b3154bcaf86373a9e6c57c594310a0
diff --git a/aos/linux_code/logging/log_replay.h b/aos/linux_code/logging/log_replay.h
new file mode 100644
index 0000000..942f26f
--- /dev/null
+++ b/aos/linux_code/logging/log_replay.h
@@ -0,0 +1,164 @@
+#ifndef AOS_LINUX_CODE_LOGGING_LOG_REPLAY_H_
+#define AOS_LINUX_CODE_LOGGING_LOG_REPLAY_H_
+
+#include <unordered_map>
+#include <string>
+#include <functional>
+#include <memory>
+
+#include "aos/linux_code/logging/binary_log_file.h"
+#include "aos/common/queue.h"
+#include "aos/common/logging/logging.h"
+#include "aos/common/macros.h"
+#include "aos/linux_code/ipc_lib/queue.h"
+#include "aos/common/queue_types.h"
+
+namespace aos {
+namespace logging {
+namespace linux_code {
+
+// Manages pulling logged queue messages out of log files.
+//
+// Basic usage:
+// - Use the Add* methods to register handlers for various message sources.
+// - Call OpenFile to open a log file.
+// - Call ProcessMessage repeatedly until it returns true.
+//
+// This code could do something to adapt similar-but-not-identical
+// messages to the current versions, but currently it will LOG(FATAL) if any of
+// the messages don't match up exactly.
+class LogReplayer {
+ public:
+ LogReplayer() {}
+
+ // Gets ready to read messages from fd.
+ // Does not take ownership of fd.
+ void OpenFile(int fd) {
+ reader_.reset(new LogFileReader(fd));
+ }
+ // Closes the currently open file.
+ void CloseCurrentFile() { reader_.reset(); }
+ // Returns true if we have a file which is currently open.
+ bool HasCurrentFile() const { return reader_.get() != nullptr; }
+
+ // Processes a single message from the currently open file.
+ // Returns true if there are no more messages in the file.
+ // This will not call any of the handlers if the next message either has no
+ // registered handlers or is not a queue message.
+ bool ProcessMessage();
+
+ // Adds a handler for messages with a certain string from a certain process.
+ // T must be a Message with the same format as the messages generated by
+ // the .q files.
+ // LOG(FATAL)s for duplicate handlers.
+ template <class T>
+ void AddHandler(const ::std::string &process_name,
+ const ::std::string &log_message,
+ ::std::function<void(const T &message)> handler) {
+ CHECK(handlers_.emplace(
+ ::std::piecewise_construct,
+ ::std::forward_as_tuple(process_name, log_message),
+ ::std::forward_as_tuple(::std::unique_ptr<StructHandlerInterface>(
+ new TypedStructHandler<T>(handler)))).second);
+ }
+
+ // Adds a handler which takes messages and places them directly on a queue.
+ // T must be a Message with the same format as the messages generated by
+ // the .q files.
+ template <class T>
+ void AddDirectQueueSender(const ::std::string &process_name,
+ const ::std::string &log_message,
+ const ::aos::Queue<T> &queue) {
+ AddHandler(process_name, log_message,
+ ::std::function<void(const T &)>(
+ QueueDumpStructHandler<T>(queue.name())));
+ }
+
+ private:
+ // A generic handler of struct log messages.
+ class StructHandlerInterface {
+ public:
+ virtual ~StructHandlerInterface() {}
+
+ virtual void HandleStruct(::aos::time::Time log_time, uint32_t type_id,
+ const void *data, size_t data_size) = 0;
+ };
+
+ // Converts struct log messages to a message type and passes it to an
+ // ::std::function.
+ template <class T>
+ class TypedStructHandler : public StructHandlerInterface {
+ public:
+ TypedStructHandler(::std::function<void(const T &message)> handler)
+ : handler_(handler) {}
+
+ void HandleStruct(::aos::time::Time log_time, uint32_t type_id,
+ const void *data, size_t data_size) override {
+ CHECK_EQ(type_id, T::GetType()->id);
+ T message;
+ CHECK_EQ(data_size, T::Size());
+ CHECK_EQ(data_size, message.Deserialize(static_cast<const char *>(data)));
+ message.sent_time = log_time;
+ handler_(message);
+ }
+
+ private:
+ const ::std::function<void(T message)> handler_;
+ };
+
+ // A callable class which dumps messages straight to a queue.
+ template <class T>
+ class QueueDumpStructHandler {
+ public:
+ QueueDumpStructHandler(const ::std::string &queue_name)
+ : queue_(RawQueue::Fetch(queue_name.c_str(), sizeof(T), T::kHash,
+ T::kQueueLength)) {}
+
+ void operator()(const T &message) {
+ LOG_STRUCT(DEBUG, "re-sending", message);
+ void *raw_message = queue_->GetMessage();
+ CHECK_NOTNULL(raw_message);
+ memcpy(raw_message, &message, sizeof(message));
+ CHECK(queue_->WriteMessage(raw_message, RawQueue::kOverride));
+ }
+
+ private:
+ ::aos::RawQueue *const queue_;
+ };
+
+ // A key for specifying log messages to give to a certain handler.
+ struct Key {
+ Key(const ::std::string &process_name, const ::std::string &log_message)
+ : process_name(process_name), log_message(log_message) {}
+
+ ::std::string process_name;
+ ::std::string log_message;
+ };
+
+ struct KeyHash {
+ size_t operator()(const Key &key) const {
+ return string_hash(key.process_name) ^
+ (string_hash(key.log_message) << 1);
+ }
+
+ private:
+ const ::std::hash<::std::string> string_hash = ::std::hash<::std::string>();
+ };
+ struct KeyEqual {
+ bool operator()(const Key &a, const Key &b) const {
+ return a.process_name == b.process_name && a.log_message == b.log_message;
+ }
+ };
+
+ ::std::unordered_map<const Key, ::std::unique_ptr<StructHandlerInterface>,
+ KeyHash, KeyEqual> handlers_;
+ ::std::unique_ptr<LogFileReader> reader_;
+
+ DISALLOW_COPY_AND_ASSIGN(LogReplayer);
+};
+
+} // namespace linux_code
+} // namespace logging
+} // namespace aos
+
+#endif // AOS_LINUX_CODE_LOGGING_LOG_REPLAY_H_