[libvirt] [PATCH v2] libxl: define a per-domain logger.
Jim Fehlig
jfehlig at suse.com
Thu Jan 5 22:45:59 UTC 2017
Cédric Bosdonnat wrote:
> libxl doesn't provide a way to write one log for each domain. Thus
> we need to demux the messages. If our logger doesn't know to which
> domain to attribute a message, then it will write it to the default
> log file.
>
> Starting with Xen 4.9 (commit f9858025 and following), libxl will
> write the domain ID in an easy to grab manner. The logger introduced
> by this commit will use it to demux the libxl log messages.
One thing I noticed when testing this on a Xen installation prior to that commit
is log files are created that will never be written to. E.g. after starting
libvirtd and one domain
# ll /var/log/libvirt/libxl/
-rw-r--r-- 1 root root 0 Jan 5 15:48 Domain-0.log
-rw-r--r-- 1 root root 17512 Jan 5 15:49 libxl-driver.log
-rw-r--r-- 1 root root 0 Jan 5 15:49 sles12sp2-hvm.log
IMO these empty, never-to-be-written-to log files might be a bit confusing to
users. AFAIK there is no way to detect up front that the underlying Xen supports
this capability right?
Regards,
Jim
>
> Thanks to the default log file, this logger will also work with older
> versions of Xen.
> ---
>
> * v2: addressed Jim's comments
>
> src/Makefile.am | 1 +
> src/libxl/libxl_conf.c | 38 +-------
> src/libxl/libxl_conf.h | 4 +-
> src/libxl/libxl_domain.c | 4 +
> src/libxl/libxl_driver.c | 2 +
> src/libxl/libxl_logger.c | 223 +++++++++++++++++++++++++++++++++++++++++++++++
> src/libxl/libxl_logger.h | 39 +++++++++
> 7 files changed, 274 insertions(+), 37 deletions(-)
> create mode 100644 src/libxl/libxl_logger.c
> create mode 100644 src/libxl/libxl_logger.h
>
> diff --git a/src/Makefile.am b/src/Makefile.am
> index b71378728..e34d52345 100644
> --- a/src/Makefile.am
> +++ b/src/Makefile.am
> @@ -851,6 +851,7 @@ LIBXL_DRIVER_SOURCES = \
> libxl/libxl_capabilities.c libxl/libxl_capabilities.h \
> libxl/libxl_domain.c libxl/libxl_domain.h \
> libxl/libxl_driver.c libxl/libxl_driver.h \
> + libxl/libxl_logger.c libxl/libxl_logger.h \
> libxl/libxl_migration.c libxl/libxl_migration.h
>
> UML_DRIVER_SOURCES = \
> diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
> index b569ddad8..ac83b51c7 100644
> --- a/src/libxl/libxl_conf.c
> +++ b/src/libxl/libxl_conf.c
> @@ -76,9 +76,7 @@ libxlDriverConfigDispose(void *obj)
>
> virObjectUnref(cfg->caps);
> libxl_ctx_free(cfg->ctx);
> - xtl_logger_destroy(cfg->logger);
> - if (cfg->logger_file)
> - VIR_FORCE_FCLOSE(cfg->logger_file);
> + libxlLoggerFree(cfg->logger);
>
> VIR_FREE(cfg->configDir);
> VIR_FREE(cfg->autostartDir);
> @@ -1356,8 +1354,6 @@ libxlDriverConfigPtr
> libxlDriverConfigNew(void)
> {
> libxlDriverConfigPtr cfg;
> - char *log_file = NULL;
> - xentoollog_level log_level = XTL_DEBUG;
> char ebuf[1024];
> unsigned int free_mem;
>
> @@ -1386,9 +1382,6 @@ libxlDriverConfigNew(void)
> if (VIR_STRDUP(cfg->channelDir, LIBXL_CHANNEL_DIR) < 0)
> goto error;
>
> - if (virAsprintf(&log_file, "%s/libxl-driver.log", cfg->logDir) < 0)
> - goto error;
> -
> if (virFileMakePath(cfg->logDir) < 0) {
> virReportError(VIR_ERR_INTERNAL_ERROR,
> _("failed to create log dir '%s': %s"),
> @@ -1397,37 +1390,13 @@ libxlDriverConfigNew(void)
> goto error;
> }
>
> - if ((cfg->logger_file = fopen(log_file, "a")) == NULL) {
> - VIR_ERROR(_("Failed to create log file '%s': %s"),
> - log_file, virStrerror(errno, ebuf, sizeof(ebuf)));
> - goto error;
> - }
> - VIR_FREE(log_file);
> -
> - switch (virLogGetDefaultPriority()) {
> - case VIR_LOG_DEBUG:
> - log_level = XTL_DEBUG;
> - break;
> - case VIR_LOG_INFO:
> - log_level = XTL_INFO;
> - break;
> - case VIR_LOG_WARN:
> - log_level = XTL_WARN;
> - break;
> - case VIR_LOG_ERROR:
> - log_level = XTL_ERROR;
> - break;
> - }
> -
> - cfg->logger =
> - (xentoollog_logger *)xtl_createlogger_stdiostream(cfg->logger_file,
> - log_level, XTL_STDIOSTREAM_SHOW_DATE);
> + cfg->logger = libxlLoggerNew(cfg->logDir, virLogGetDefaultPriority());
> if (!cfg->logger) {
> VIR_ERROR(_("cannot create logger for libxenlight, disabling driver"));
> goto error;
> }
>
> - if (libxl_ctx_alloc(&cfg->ctx, LIBXL_VERSION, 0, cfg->logger)) {
> + if (libxl_ctx_alloc(&cfg->ctx, LIBXL_VERSION, 0, (xentoollog_logger *)cfg->logger)) {
> VIR_ERROR(_("cannot initialize libxenlight context, probably not "
> "running in a Xen Dom0, disabling driver"));
> goto error;
> @@ -1478,7 +1447,6 @@ libxlDriverConfigNew(void)
> return cfg;
>
> error:
> - VIR_FREE(log_file);
> virObjectUnref(cfg);
> return NULL;
> }
> diff --git a/src/libxl/libxl_conf.h b/src/libxl/libxl_conf.h
> index 851f3afb4..69d78851a 100644
> --- a/src/libxl/libxl_conf.h
> +++ b/src/libxl/libxl_conf.h
> @@ -41,6 +41,7 @@
> # include "locking/lock_manager.h"
> # include "virfirmware.h"
> # include "libxl_capabilities.h"
> +# include "libxl_logger.h"
>
> # define LIBXL_DRIVER_NAME "xenlight"
> # define LIBXL_VNC_PORT_MIN 5900
> @@ -74,8 +75,7 @@ struct _libxlDriverConfig {
> unsigned int version;
>
> /* log stream for driver-wide libxl ctx */
> - FILE *logger_file;
> - xentoollog_logger *logger;
> + libxlLoggerPtr logger;
> /* libxl ctx for driver wide ops; getVersion, getNodeInfo, ... */
> libxl_ctx *ctx;
>
> diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c
> index 5cde576ef..3bc468f61 100644
> --- a/src/libxl/libxl_domain.c
> +++ b/src/libxl/libxl_domain.c
> @@ -809,6 +809,8 @@ libxlDomainCleanup(libxlDriverPrivatePtr driver,
> VIR_FREE(xml);
> }
>
> + libxlLoggerCloseFile(cfg->logger, vm->def->id);
> +
> virDomainObjRemoveTransientDef(vm);
> virObjectUnref(cfg);
> }
> @@ -1291,6 +1293,8 @@ libxlDomainStart(libxlDriverPrivatePtr driver,
> */
> vm->def->id = domid;
>
> + libxlLoggerOpenFile(cfg->logger, domid, vm->def->name);
> +
> /* Always enable domain death events */
> if (libxl_evenable_domain_death(cfg->ctx, vm->def->id, 0, &priv->deathW))
> goto destroy_dom;
> diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
> index 7e5d9b69e..6a4ecddef 100644
> --- a/src/libxl/libxl_driver.c
> +++ b/src/libxl/libxl_driver.c
> @@ -406,6 +406,8 @@ libxlReconnectDomain(virDomainObjPtr vm,
> /* Update domid in case it changed (e.g. reboot) while we were gone? */
> vm->def->id = d_info.domid;
>
> + libxlLoggerOpenFile(cfg->logger, vm->def->id, vm->def->name);
> +
> /* Update hostdev state */
> if (virHostdevUpdateActiveDomainDevices(hostdev_mgr, LIBXL_DRIVER_NAME,
> vm->def, hostdev_flags) < 0)
> diff --git a/src/libxl/libxl_logger.c b/src/libxl/libxl_logger.c
> new file mode 100644
> index 000000000..d8ccdd852
> --- /dev/null
> +++ b/src/libxl/libxl_logger.c
> @@ -0,0 +1,223 @@
> +/*
> + * libxl_logger.c: libxl logger implementation
> + *
> + * Copyright (c) 2016 SUSE LINUX Products GmbH, Nuernberg, Germany.
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library. If not, see
> + * <http://www.gnu.org/licenses/>.
> + *
> + * Authors:
> + * Cédric Bosdonnat <cbosdonnat at suse.com>
> + */
> +#include <config.h>
> +
> +#include <string.h>
> +#include <libxl.h>
> +
> +#include "internal.h"
> +#include "libxl_logger.h"
> +#include "util/viralloc.h"
> +#include "util/virerror.h"
> +#include "util/virfile.h"
> +#include "util/virhash.h"
> +#include "util/virstring.h"
> +#include "util/virtime.h"
> +
> +#define VIR_FROM_THIS VIR_FROM_LIBXL
> +
> +VIR_LOG_INIT("libxl.libxl_logger");
> +
> +typedef struct xentoollog_logger_libvirt xentoollog_logger_libvirt;
> +
> +struct xentoollog_logger_libvirt {
> + xentoollog_logger vtable;
> + xentoollog_level minLevel;
> + const char *logDir;
> +
> + /* map storing the opened fds: "domid" -> FILE* */
> + virHashTablePtr files;
> + FILE *defaultLogFile;
> +};
> +
> +static void
> +libxlLoggerFileFree(void *payload, const void *key ATTRIBUTE_UNUSED)
> +{
> + FILE *file = payload;
> + VIR_FORCE_FCLOSE(file);
> + file = NULL;
> +}
> +
> +ATTRIBUTE_FMT_PRINTF(5, 0) static void
> +libvirt_vmessage(xentoollog_logger *logger_in,
> + xentoollog_level level,
> + int errnoval,
> + const char *context,
> + const char *format,
> + va_list args)
> +{
> + xentoollog_logger_libvirt *lg = (xentoollog_logger_libvirt *)logger_in;
> + FILE *logFile = lg->defaultLogFile;
> + char timestamp[VIR_TIME_STRING_BUFLEN];
> + char *message = NULL;
> + char *start, *end;
> + char ebuf[1024];
> +
> + VIR_DEBUG("libvirt_vmessage: context='%s' format='%s'", context, format);
> +
> + if (level < lg->minLevel)
> + return;
> +
> + if (virVasprintf(&message, format, args) < 0)
> + return;
> +
> + /* Should we print to a domain-specific log file? */
> + if ((start = strstr(message, ": Domain ")) &&
> + (end = strstr(start + 9, ":"))) {
> + FILE *domainLogFile;
> +
> + VIR_DEBUG("Found domain log message");
> +
> + start = start + 9;
> + *end = '\0';
> +
> + domainLogFile = virHashLookup(lg->files, start);
> + if (domainLogFile)
> + logFile = domainLogFile;
> +
> + *end = ':';
> + }
> +
> + /* Do the actual print to the log file */
> + if (virTimeStringNowRaw(timestamp) < 0)
> + timestamp[0] = '\0';
> +
> + fprintf(logFile, "%s: ", timestamp);
> + if (context)
> + fprintf(logFile, "%s: ", context);
> +
> + fprintf(logFile, "%s", message);
> +
> + if (errnoval >= 0)
> + fprintf(logFile, ": %s", virStrerror(errnoval, ebuf, sizeof(ebuf)));
> +
> + fputc('\n', logFile);
> + fflush(logFile);
> +
> + VIR_FREE(message);
> +}
> +
> +static void
> +libvirt_progress(xentoollog_logger *logger_in ATTRIBUTE_UNUSED,
> + const char *context ATTRIBUTE_UNUSED,
> + const char *doingwhat ATTRIBUTE_UNUSED,
> + int percent ATTRIBUTE_UNUSED,
> + unsigned long done ATTRIBUTE_UNUSED,
> + unsigned long total ATTRIBUTE_UNUSED)
> +{
> + /* This function purposedly does nothing: it's no logging info */
> +}
> +
> +static void
> +libvirt_destroy(xentoollog_logger *logger_in)
> +{
> + xentoollog_logger_libvirt *lg = (xentoollog_logger_libvirt*)logger_in;
> + VIR_FREE(lg);
> +}
> +
> +
> +libxlLoggerPtr libxlLoggerNew(const char *logDir,
> + virLogPriority minLevel)
> +{
> + xentoollog_logger_libvirt logger;
> + libxlLoggerPtr logger_out = NULL;
> + char *path = NULL;
> +
> + switch (minLevel) {
> + case VIR_LOG_DEBUG:
> + logger.minLevel = XTL_DEBUG;
> + break;
> + case VIR_LOG_INFO:
> + logger.minLevel = XTL_INFO;
> + break;
> + case VIR_LOG_WARN:
> + logger.minLevel = XTL_WARN;
> + break;
> + case VIR_LOG_ERROR:
> + logger.minLevel = XTL_ERROR;
> + break;
> + }
> + logger.logDir = logDir;
> +
> + if ((logger.files = virHashCreate(3, libxlLoggerFileFree)) == NULL)
> + return NULL;
> +
> + if (virAsprintf(&path, "%s/libxl-driver.log", logDir) < 0)
> + goto error;
> +
> + if ((logger.defaultLogFile = fopen(path, "a")) == NULL)
> + goto error;
> +
> + logger_out = XTL_NEW_LOGGER(libvirt, logger);
> +
> + cleanup:
> + VIR_FREE(path);
> + return logger_out;
> +
> + error:
> + virHashFree(logger.files);
> + goto cleanup;
> +}
> +
> +void libxlLoggerFree(libxlLoggerPtr logger)
> +{
> + xentoollog_logger *xtl_logger = (xentoollog_logger*)logger;
> + if (logger->defaultLogFile)
> + VIR_FORCE_FCLOSE(logger->defaultLogFile);
> + virHashFree(logger->files);
> + xtl_logger_destroy(xtl_logger);
> +}
> +
> +void libxlLoggerOpenFile(libxlLoggerPtr logger, int id, const char *name)
> +{
> + char *path = NULL;
> + FILE *logFile = NULL;
> + char *domidstr = NULL;
> + char ebuf[1024];
> +
> + if (virAsprintf(&path, "%s/%s.log", logger->logDir, name) < 0 ||
> + virAsprintf(&domidstr, "%d", id) < 0)
> + goto cleanup;
> +
> + if (!(logFile = fopen(path, "a"))) {
> + VIR_WARN("Failed to open log file %s: %s",
> + path, virStrerror(errno, ebuf, sizeof(ebuf)));
> + goto cleanup;
> + }
> + ignore_value(virHashAddEntry(logger->files, domidstr, logFile));
> +
> + cleanup:
> + VIR_FREE(path);
> + VIR_FREE(domidstr);
> +}
> +
> +void libxlLoggerCloseFile(libxlLoggerPtr logger, int id)
> +{
> + char *domidstr = NULL;
> + if (virAsprintf(&domidstr, "%d", id) < 0)
> + return;
> +
> + ignore_value(virHashRemoveEntry(logger->files, domidstr));
> +
> + VIR_FREE(domidstr);
> +}
> diff --git a/src/libxl/libxl_logger.h b/src/libxl/libxl_logger.h
> new file mode 100644
> index 000000000..88c2868eb
> --- /dev/null
> +++ b/src/libxl/libxl_logger.h
> @@ -0,0 +1,39 @@
> +/*
> + * libxl_logger.h: libxl logger implementation
> + *
> + * Copyright (c) 2016 SUSE LINUX Products GmbH, Nuernberg, Germany.
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library. If not, see
> + * <http://www.gnu.org/licenses/>.
> + *
> + * Authors:
> + * Cédric Bosdonnat <cbosdonnat at suse.com>
> + */
> +
> +#ifndef __LIBXL_LOGGER_H
> +# define __LIBXL_LOGGER_H
> +
> +# include "util/virlog.h"
> +
> +typedef struct xentoollog_logger_libvirt libxlLogger;
> +typedef libxlLogger *libxlLoggerPtr;
> +
> +libxlLoggerPtr libxlLoggerNew(const char *logDir,
> + virLogPriority minLevel);
> +void libxlLoggerFree(libxlLoggerPtr logger);
> +
> +void libxlLoggerOpenFile(libxlLoggerPtr logger, int id, const char *name);
> +void libxlLoggerCloseFile(libxlLoggerPtr logger, int id);
> +
> +#endif /* __LIBXL_LOGGER_H */
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