[PATCH 2/2] logging: add log cleanup for obsolete domains
Martin Kletzander
mkletzan at redhat.com
Wed Nov 30 10:49:01 UTC 2022
On Mon, Nov 21, 2022 at 03:29:57PM +0600, Oleg Vasilev wrote:
>Before, logs from deleted machines have been piling up, since there were
>no garbadge collection mechanism. Now virtlogd can be configured to
>periodically scan log folder for orphan logs with no recent modfications
>and delete it.
>
>Signed-off-by: Oleg Vasilev <oleg.vasilev at virtuozzo.com>
>---
> src/logging/log_daemon_config.c | 9 +++
> src/logging/log_daemon_config.h | 3 +
> src/logging/log_handler.c | 108 +++++++++++++++++++++++++++++++
> src/logging/test_virtlogd.aug.in | 2 +
> src/logging/virtlogd.aug | 2 +
> src/logging/virtlogd.conf | 7 ++
> 6 files changed, 131 insertions(+)
>
>diff --git a/src/logging/log_daemon_config.c b/src/logging/log_daemon_config.c
>index 4436745488..248bd927d3 100644
>--- a/src/logging/log_daemon_config.c
>+++ b/src/logging/log_daemon_config.c
>@@ -28,6 +28,7 @@
> #include "virutil.h"
>
> #define VIR_FROM_THIS VIR_FROM_CONF
>+#define DEFAULT_LOG_ROOT LOCALSTATEDIR "/log/libvirt/"
>
> VIR_LOG_INIT("logging.log_daemon_config");
>
>@@ -60,6 +61,7 @@ virLogDaemonConfigNew(bool privileged G_GNUC_UNUSED)
> data->admin_max_clients = 5000;
> data->max_size = 1024 * 1024 * 2;
> data->max_backups = 3;
>+ data->max_age_days = 0;
>
> return data;
> }
>@@ -72,6 +74,7 @@ virLogDaemonConfigFree(virLogDaemonConfig *data)
>
> g_free(data->log_filters);
> g_free(data->log_outputs);
>+ g_free(data->log_root);
>
> g_free(data);
> }
>@@ -94,6 +97,12 @@ virLogDaemonConfigLoadOptions(virLogDaemonConfig *data,
> return -1;
> if (virConfGetValueSizeT(conf, "max_backups", &data->max_backups) < 0)
> return -1;
>+ if (virConfGetValueSizeT(conf, "max_age_days", &data->max_age_days) < 0)
>+ return -1;
>+ if (virConfGetValueString(conf, "log_root", &data->log_root) < 0)
>+ return -1;
>+ if (!data->log_root)
>+ data->log_root = g_strdup(DEFAULT_LOG_ROOT);
>
> return 0;
> }
>diff --git a/src/logging/log_daemon_config.h b/src/logging/log_daemon_config.h
>index 2ab0f67c96..43922feedf 100644
>--- a/src/logging/log_daemon_config.h
>+++ b/src/logging/log_daemon_config.h
>@@ -33,6 +33,9 @@ struct _virLogDaemonConfig {
>
> size_t max_backups;
> size_t max_size;
>+
>+ char *log_root;
>+ size_t max_age_days;
> };
>
>
>diff --git a/src/logging/log_handler.c b/src/logging/log_handler.c
>index 7342404b00..2690d7519b 100644
>--- a/src/logging/log_handler.c
>+++ b/src/logging/log_handler.c
>@@ -33,6 +33,7 @@
> #include <unistd.h>
> #include <fcntl.h>
> #include <poll.h>
>+#include <fnmatch.h>
>
> #include "configmake.h"
>
>@@ -42,6 +43,10 @@ VIR_LOG_INIT("logging.log_handler");
>
> #define DEFAULT_MODE 0600
>
>+/* Cleanup log root (/var/log/libvirt) and all subfolders (e.g. /var/log/libvirt/qemu) */
>+#define CLEANUP_OBSOLETE_LOG_DEPTH 1
>+#define CLEANUP_OBSOLETE_LOG_TIMEOUT_MS (24 * 3600 * 1000) /* One day */
>+
> typedef struct _virLogHandlerLogFile virLogHandlerLogFile;
> struct _virLogHandlerLogFile {
> virRotatingFileWriter *file;
>@@ -60,6 +65,8 @@ struct _virLogHandler {
> bool privileged;
> virLogDaemonConfig *config;
>
>+ int cleanup_log_timer;
>+
> virLogHandlerLogFile **files;
> size_t nfiles;
>
>@@ -81,6 +88,93 @@ virLogHandlerOnceInit(void)
>
> VIR_ONCE_GLOBAL_INIT(virLogHandler);
>
>+static void
>+virLogHandlerMaybeCleanupObsoleteLog(virLogHandler *handler,
>+ const char* path) {
>+ size_t i;
>+ bool remove = true;
>+
>+ if (fnmatch("*.log*", path, 0))
>+ return;
>+
>+ virObjectLock(handler);
If you use a lock guard:
VIR_LOCK_GUARD lock = virObjectLockGuard(handler);
then ...
>+ for (i = 0; i < handler->nfiles; i++) {
>+ virLogHandlerLogFile *file = handler->files[i];
>+ if (STRPREFIX(path, virRotatingFileWriterGetPath(file->file))) {
>+ remove = false;
>+ break;
>+ }
... this condition body can just be replaced with `return`, and
>+ }
>+ virObjectUnlock(handler);
>+
>+ if (!remove)
>+ return;
>+
the unlocking and this above condition removed.
>+ if (unlink(path) < 0) {
>+ virReportSystemError(errno, _("Unable to delete %s"), path);
>+ }
>+}
>+
>+static void
>+virLogHandlerCleanupObsoleteLogsFolder(virLogHandler *handler,
>+ time_t oldest_to_keep,
>+ const char *path,
>+ int depth_left)
>+{
>+ DIR *dir;
>+ struct dirent *entry;
>+ char *newpath;
>+ struct stat sb;
>+
>+ if (virDirOpenIfExists(&dir, path) < 0)
>+ return;
>+
>+ while (virDirRead(dir, &entry, path) > 0) {
>+ if (STREQ(entry->d_name, "."))
>+ continue;
>+ if (STREQ(entry->d_name, ".."))
>+ continue;
>+
>+ newpath = g_strdup_printf("%s/%s", path, entry->d_name);
>+
If you make this newpath a `g_autofree char *` in the while loop then
you can replace all `goto next` with `continue` and remove the label and
VIR_FREE() call.
>+ if (stat(newpath, &sb) < 0) {
>+ virReportSystemError(errno, _("Unable to stat %s"), newpath);
>+ goto next;
>+ }
>+
>+ if (S_ISDIR(sb.st_mode)) {
>+ if (depth_left > 0)
>+ virLogHandlerCleanupObsoleteLogsFolder(handler, oldest_to_keep, newpath, depth_left - 1);
>+ goto next;
>+ }
>+
>+ if (!S_ISREG(sb.st_mode)) {
>+ goto next;
>+ }
>+
>+ if (sb.st_mtim.tv_sec > oldest_to_keep) {
>+ goto next;
>+ }
>+
>+ virLogHandlerMaybeCleanupObsoleteLog(handler, newpath);
>+
>+ next:
>+ VIR_FREE(newpath);
>+ }
>+
>+ virDirClose(dir);
>+}
>+
>+static void
>+virLogHandlerCleanupObsoleteLogs(int timer G_GNUC_UNUSED, void* opaque)
>+{
>+ virLogHandler *handler = opaque;
>+ time_t oldest_to_keep = time(NULL) - 3600 * 24 * handler->config->max_age_days;
>+ const char *log_root = handler->config->log_root;
>+
>+ virLogHandlerCleanupObsoleteLogsFolder(handler, oldest_to_keep, log_root, CLEANUP_OBSOLETE_LOG_DEPTH);
>+}
>+
>
> static void
> virLogHandlerLogFileFree(virLogHandlerLogFile *file)
>@@ -201,7 +295,19 @@ virLogHandlerNew(bool privileged,
> handler->inhibitor = inhibitor;
> handler->opaque = opaque;
>
>+ if (config->max_age_days > 0) {
>+ handler->cleanup_log_timer = virEventAddTimeout(CLEANUP_OBSOLETE_LOG_TIMEOUT_MS,
>+ virLogHandlerCleanupObsoleteLogs,
>+ handler, NULL);
>+ if (handler->cleanup_log_timer < 0)
>+ goto error;
>+ }
>+
> return handler;
>+
>+ error:
>+ virObjectUnref(handler);
>+ return NULL;
> }
>
>
>@@ -344,6 +450,8 @@ virLogHandlerDispose(void *obj)
> virLogHandlerLogFileFree(handler->files[i]);
> }
> g_free(handler->files);
>+ if (handler->cleanup_log_timer != 0)
>+ virEventRemoveTimeout(handler->cleanup_log_timer);
> }
>
>
>diff --git a/src/logging/test_virtlogd.aug.in b/src/logging/test_virtlogd.aug.in
>index cd5b0d91f8..8dfad39506 100644
>--- a/src/logging/test_virtlogd.aug.in
>+++ b/src/logging/test_virtlogd.aug.in
>@@ -9,3 +9,5 @@ module Test_virtlogd =
> { "admin_max_clients" = "5" }
> { "max_size" = "2097152" }
> { "max_backups" = "3" }
>+ { "max_age_days" = "0" }
>+ { "log_root" = "/var/log/libvirt" }
>diff --git a/src/logging/virtlogd.aug b/src/logging/virtlogd.aug
>index 0f1b290c72..bdf61dea6e 100644
>--- a/src/logging/virtlogd.aug
>+++ b/src/logging/virtlogd.aug
>@@ -31,6 +31,8 @@ module Virtlogd =
> | int_entry "admin_max_clients"
> | int_entry "max_size"
> | int_entry "max_backups"
>+ | int_entry "max_age_days"
>+ | str_entry "log_root"
>
> (* Each entry in the config is one of the following three ... *)
> let entry = logging_entry
>diff --git a/src/logging/virtlogd.conf b/src/logging/virtlogd.conf
>index c53a1112bd..d88ce31327 100644
>--- a/src/logging/virtlogd.conf
>+++ b/src/logging/virtlogd.conf
>@@ -101,3 +101,10 @@
> # Maximum number of backup files to keep. Defaults to 3,
> # not including the primary active file
> #max_backups = 3
>+
>+# Maximum age for log files to live after the last modification.
>+# Defaults to 0, which means "forever".
>+#max_age_days = 0
>+
>+# Root of all logs managed by virtlogd. Used to GC logs from obsolete machines.
>+#log_root = "/var/log/libvirt"
One thing I am afraid of is that if there is some other log that is
unused for max_age_days, but is not managed by virlogd, then it will get
removed as well, but it might not be what users want. Thankfully this
is an opt-in, but I would sleep more calmly if there was a warning with
explanation of what this might do outside of its scope.
One more thing is that if larger logs are rotated, then this would
remove the old ones even if they are kept as number of backups. That
seems like something that should be avoided (probably not even
configurable).
>--
>2.38.1
>
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