Re: [libvirt] [PATCH 4/5] Add detailed error information to journal

When logging an error, don't throw away the detailed information. Example record when using the journald output: MESSAGE=Domain not found PRIORITY=4 LIBVIRT_SOURCE=error CODE_FILE=../../src/test/test_driver.c CODE_LINE=1405 CODE_FUNC=testLookupDomainByName DOMAIN=12 CODE=42 STR1=Domain not found STR2= The format used in other output destinations (e.g. "syslog", "file") is still unchanged. The "domain" and "code" numbers are part of the libvirt ABI in <libvirt/virterror.h>; therefore log processing tools can rely on them, unlike the text log string (which is translated depending on locale, and may be modified for other reasons as well). Alternatively, the "domain" and "code" fields could contain strings instead of numbers, but it's not clear that it's worth it: Advantages of numbers: * the numbers are shorter * the ABI guarantees that the numbers won't change Disadvantages of strings: * adding a ABI-stable string mapping for virErrorNumber would result in additional work each time a new error number is added (note that virErrorMsg cannot be used for this because it is translated) * a change in the string mapping would be less likely to be noticed The advantage of using strings is more readability, but note that the "msg" field above already contains a readable description of the error.

@@ -676,10 +678,39 @@ virRaiseErrorFull(const char *filename ATTRIBUTE_UNUSED, priority = virErrorLevelPriority(level); if (virErrorLogPriorityFilter) priority = virErrorLogPriorityFilter(to, priority); + + i = 0; +#define META_ADD_STRING(KEY, VALUE) \ + do { \ + meta[i].key = (KEY); \ + meta[i].s = (VALUE); \ + i++; \ + } while (0) +#define META_ADD_INT(KEY, VALUE) \ + do { \ + meta[i].key = (KEY); \ + meta[i].s = NULL; \ + meta[i].i = (VALUE); \ + i++; \ + } while (0) + + META_ADD_INT("DOMAIN", domain); + META_ADD_INT("CODE", code); + if (str1 != NULL) + META_ADD_STRING("STR1", str1); + if (str2 != NULL) + META_ADD_STRING("STR2", str2); + if (str3 != NULL) + META_ADD_STRING("STR3", str3); + if (int1 != -1) + META_ADD_INT("INT1", int1); + if (int2 != -1) + META_ADD_INT("INT2", int2);