This document explains how to get started with syslogger APIs.
Component manifest dependency
Ensure that your component has the required capabilities to log by including the following in your component manifest:
{
include: [
"syslog/client.shard.cml"
],
...
}
The syslog library will fallback to stderr if the LogSink connection fails.
Default configuration
The global logger is lazily instantiated on the first use of the API. The default configuration for the global logger is:
- Use process name as the tag
- Write logs to
fuchsia.logger.LogSink - Min log level of
fuchsia_logging::LogSeverity::Info
In C++
BUILD.gn dependency
//sdk/lib/syslog/cpp
Log messages
#include <lib/syslog/cpp/macros.h>
FX_LOGS(INFO) << "my message";
FX_LOGST(INFO, "tag") << "my message";
Set tags
By default, the process name is used as the tag, but this can be changed by
calling fuchsia_logging::SetTags.
#include <lib/syslog/cpp/log_settings.h>
int main(int argc, char** argv) {
fuchsia_logging::SetTags({"tag1", "tag2"});
}
Set settings
#include "<lib/syslog/cpp/log_settings.h>
int main(int argc, char** argv) {
fuchsia_logging::LogSettings settings = {
.min_log_level = fuchsia_logging::LOG_ERROR,
};
fuchsia_logging::SetLogSettings(settings, {"tag1", "tag2"});
}
Set settings from command line
#include "src/lib/fxl/command_line.h"
#include "src/lib/fxl/log_settings_command_line.h"
int main(int argc, char** argv) {
auto command_line = fxl::CommandLineFromArgcArgv(argc, argv);
fxl::SetLogSettingsFromCommandLine(command_line, {"my_program"});
}
GTest main with syslog initialized from command line
No initialization is required for using the default configuration of syslog. If you would like your test suite to change the configuration based on command line arguments (e.g. --verbose), use:
//src/lib/fxl/test:gtest_main