Work around duplicate headers at the start of logs
Somehow, we have managed to log duplicate headers at the beginning of
some of our logs.
log_11_data/11/aos/aos.message_bridge.Timestamp.part0.bfbs.xz and
friends seem to be where we are finding these issues. Hide this
behavior behind a flag.
We urgently need a follow-up commit which fixes the log writer so it
doesn't write duplicate headers. Unfortuantely, we have valuable data
logged with duplicate headers in it so we need this workaround.
Change-Id: I905023fc647547fda5004b303f1a6988ec311a93
Signed-off-by: Austin Schuh <austin.schuh@bluerivertech.com>
diff --git a/aos/events/logging/logfile_utils.h b/aos/events/logging/logfile_utils.h
index ee13a7c..f876d25 100644
--- a/aos/events/logging/logfile_utils.h
+++ b/aos/events/logging/logfile_utils.h
@@ -199,8 +199,12 @@
flatbuffers::FlatBufferBuilder *fbb, const Context &context,
int channel_index, LogType log_type);
+// Reads the last header from a log file. This handles any duplicate headers
+// that were written.
std::optional<SizePrefixedFlatbufferVector<LogFileHeader>> ReadHeader(
std::string_view filename);
+// Reads the Nth message from a log file, excluding the header. Note: this
+// doesn't handle duplicate headers.
std::optional<SizePrefixedFlatbufferVector<MessageHeader>> ReadNthMessage(
std::string_view filename, size_t n);