icinga2/lib/base/journaldlogger.cpp
Tobias Deiminger 173caa42aa Add a JournaldLogger
As proposed in #8857, this adds a Logger subclass that writes structured
log messages via journald's native protocol by calling sd_journal_sendv.
The feature therefore depends on the systemd library. sd_journal_sendv is
available since the early days (systemd v38), so a version check is
probably superflous.

We add the following fields to each record:
- MESSAGE: The log message
- PRIORITY (aka severity): Numeric severity as in RFC5424 section 6.2.1
- SYSLOG_FACILITY: Numeric facility as in RFC5424 section 6.2.1
- SYSLOG_IDENTIFIER: If provided, use value from configuration.
  Else use systemd's default behaior, which is to determine the field
  by using libc's program_invocation_short_name, resulting in "icinga2".
- ICINGA2_FACILITY: Facility as in Log::Log(..., String facility, ...),
  e.g. "ApiListener"
- some more fields are added automatically by systemd

Fields are stored indexed, so we can do fast queries for certain field
values. Example:

$ journalctl -t icinga2 ICINGA2_FACILITY=ApiListener -n 5

Syslog compatiblity is ratained because good old tag, severity and facility
is stored along, and systemd can forward to syslog daemons.

See also https://systemd.io/JOURNAL_NATIVE_PROTOCOL/.
2021-09-23 16:08:11 +02:00

88 lines
2.6 KiB
C++

/* Icinga 2 | (c) 2021 Icinga GmbH | GPLv2+ */
#include "base/i2-base.hpp"
#if !defined(_WIN32) && defined(HAVE_SYSTEMD)
#include "base/journaldlogger.hpp"
#include "base/journaldlogger-ti.cpp"
#include "base/configtype.hpp"
#include "base/statsfunction.hpp"
#include "base/sysloglogger.hpp"
#include <systemd/sd-journal.h>
using namespace icinga;
REGISTER_TYPE(JournaldLogger);
REGISTER_STATSFUNCTION(JournaldLogger, &JournaldLogger::StatsFunc);
void JournaldLogger::StatsFunc(const Dictionary::Ptr& status, const Array::Ptr&)
{
DictionaryData nodes;
for (const JournaldLogger::Ptr& journaldlogger : ConfigType::GetObjectsByType<JournaldLogger>()) {
nodes.emplace_back(journaldlogger->GetName(), 1); //add more stats
}
status->Set("journaldlogger", new Dictionary(std::move(nodes)));
}
void JournaldLogger::OnConfigLoaded()
{
ObjectImpl<JournaldLogger>::OnConfigLoaded();
m_ConfiguredJournalFields.clear();
m_ConfiguredJournalFields.push_back(
String("SYSLOG_FACILITY=") + Value(SyslogHelper::FacilityToNumber(GetFacility())));
const String identifier = GetIdentifier();
if (!identifier.IsEmpty()) {
m_ConfiguredJournalFields.push_back(String("SYSLOG_IDENTIFIER=" + identifier));
}
}
void JournaldLogger::ValidateFacility(const Lazy<String>& lvalue, const ValidationUtils& utils)
{
ObjectImpl<JournaldLogger>::ValidateFacility(lvalue, utils);
if (!SyslogHelper::ValidateFacility(lvalue()))
BOOST_THROW_EXCEPTION(ValidationError(this, { "facility" }, "Invalid facility specified."));
}
/**
* Processes a log entry and outputs it to journald.
*
* @param entry The log entry.
*/
void JournaldLogger::ProcessLogEntry(const LogEntry& entry)
{
const std::vector<String> sdFields {
String("MESSAGE=") + entry.Message.GetData(),
String("PRIORITY=") + Value(SyslogHelper::SeverityToNumber(entry.Severity)),
String("ICINGA2_FACILITY=") + entry.Facility,
};
SystemdJournalSend(sdFields);
}
void JournaldLogger::Flush()
{
/* Nothing to do here. */
}
void JournaldLogger::SystemdJournalSend(const std::vector<String>& varJournalFields) const
{
struct iovec iovec[m_ConfiguredJournalFields.size() + varJournalFields.size()];
int iovecCount = 0;
for (const String& journalField: m_ConfiguredJournalFields) {
iovec[iovecCount] = IovecFromString(journalField);
iovecCount++;
}
for (const String& journalField: varJournalFields) {
iovec[iovecCount] = IovecFromString(journalField);
iovecCount++;
}
sd_journal_sendv(iovec, iovecCount);
}
struct iovec JournaldLogger::IovecFromString(const String& s) {
return { const_cast<char *>(s.CStr()), s.GetLength() };
}
#endif /* !_WIN32 && HAVE_SYSTEMD */