[virt-tools-list] [vhostmd PATCH 1/2] Remove libserialclient
Jim Fehlig
jfehlig at suse.com
Mon Dec 10 23:41:04 UTC 2018
On 12/7/18 11:12 AM, Michael Trapp wrote:
> There is no need to keep the dump_virtio code in a separate library.
> Revert libserialclient changes and move the code to libmetrics.
>
> ---
>
> vm-dump-metrics tries to access the metrics disk without a check of the
> transport methods because the access is located in the libmetrics
> constructor this can't be changed in vm-dump-metrics.
Yeah, it is tough to change the constructor without changing the library
behavior in some small way.
>
> libmetrics.c:
> void __attribute__ ((constructor)) libmetrics_init(void)
> ...
> if (read_mdisk(mdisk) != 0) {
> libmsg("%s(): Unable to read metrics disk\n", __func__);
>
> Whith virtio transport we can't expect a metrics disk and should avoid the
> error. One option is to remove read_mdisk() from the constructor, initialize
> mdisk->sum and rely on the read_mdisk() call in read_mdisk_sum().
I never liked the idea of this library and as I recall protested its addition to
vhostmd many, many years ago :-). I preferred a simple app (aka vm-dump-metrics)
that would simply dump an XML doc of metrics and let the consumer do with it as
they please. Do you use the library, or only vm-dump-metrics?
> This should be discussed and fixed in another patch.
While we're on the topic, I'll discuss it briefly here, but yes needs to be
fixed in a separate patch.
I can think of two options for a fix. Option 1, as you suggest, is to remove
read_mdisk() from the constructor. IMO, mdisk->sum should be left at 0 as
initialized by mdisk_alloc(). We'd need to fixup dump_metrics() to handle that,
similar to get_metrics().
Option 2 is adjust the constructor to try populating the metric_disk structure
with read_mdisk() first, then with virtio, and only fail if both are
unavailable. One upshot of this approach is that the get*_metric APIs would work
with virtio by adjusting get_metrics() to handle disk or virtio transport. One
downside of this approach is abusing the poorly named "metric_disk" structure.
I.e. we'd be populating the structure from virtio instead of a disk. In
hindsight "metric_source" or "metric_block" or "metric_packet" or about anything
else would have been a better name than "metric_disk" :-).
I tend to prefer option 2 since the get*_metric APIs would work with virtio
transport. Do you have a preference, or alternative option?
>
> libmetrics/Makefile.am | 18 +---
> libmetrics/libmetrics.c | 131 ++++++++++++++++++++++++++
> libmetrics/libmetrics.h | 4 -
> libmetrics/libserialclient.c | 172 -----------------------------------
> libmetrics/libserialclient.h | 30 ------
> 5 files changed, 133 insertions(+), 222 deletions(-)
> delete mode 100644 libmetrics/libserialclient.c
> delete mode 100644 libmetrics/libserialclient.h
As far as this patch goes:
Reviewed-by: Jim Fehlig <jfehlig at suse.com>
Regards,
Jim
>
> diff --git a/libmetrics/Makefile.am b/libmetrics/Makefile.am
> index 468f08f..254b2c8 100644
> --- a/libmetrics/Makefile.am
> +++ b/libmetrics/Makefile.am
> @@ -6,7 +6,7 @@ if WITH_XENSTORE
> AM_CFLAGS += -DWITH_XENSTORE
> endif
>
> -lib_LTLIBRARIES=libmetrics.la libserialclient.la
> +lib_LTLIBRARIES=libmetrics.la
>
> libmetricsincdir=$(includedir)/vhostmd
> libmetricsinc_HEADERS = libmetrics.h
> @@ -15,21 +15,7 @@ libmetrics_la_SOURCES = \
> libmetrics.c \
> vm_metrics.c \
> host_metrics.c \
> - libserialclient.c \
> libmetrics.h
>
> libmetrics_la_DEPENDENCIES = \
> - libmetrics.h \
> - libserialclient.h
> -
> -
> -libserialclientincdir=
> -libserialclientinc_HEADERS = libserialclient.h
> -
> -libserialclient_la_SOURCES = \
> - libserialclient.c \
> - libserialclient.h
> -
> -libserialclient_la_DEPENDENCIES = \
> - libserialclient.h
> -
> + libmetrics.h
> diff --git a/libmetrics/libmetrics.c b/libmetrics/libmetrics.c
> index bc3ba1d..0a5e3ee 100644
> --- a/libmetrics/libmetrics.c
> +++ b/libmetrics/libmetrics.c
> @@ -775,3 +775,134 @@ out:
> }
> #endif
>
> +/*
> + * dump metrics from virtio serial port to buffer
> + */
> +static char *get_virtio_metrics(void)
> +{
> + const char request[] = "GET /metrics/XML\n\n", end_token[] = "\n\n";
> + const char dev[] = "/dev/virtio-ports/org.github.vhostmd.1";
> +
> + char *response = NULL;
> + int fd = -1;
> + size_t pos;
> + size_t buf_size = (1 << 16);
> + const size_t req_len = (size_t) strlen(request);
> + const time_t start_time = time(NULL);
> +
> + response = calloc(1UL, buf_size);
> + if (response == NULL)
> + goto error;
> +
> + fd = open(dev, O_RDWR | O_NONBLOCK);
> +
> + if (fd < 0) {
> + libmsg("Error, unable to export metrics: open(%s) %s\n",
> + dev, strerror(errno));
> + goto error;
> + }
> +
> + pos = 0;
> + while (pos < req_len) {
> + ssize_t len = write(fd, &request[pos], req_len - pos);
> + if (len > 0)
> + pos += (size_t) len;
> + else {
> + if (errno == EAGAIN)
> + usleep(10000);
> + else
> + goto error;
> + }
> + }
> +
> + pos = 0;
> + do {
> + ssize_t len = read(fd, &response[pos], buf_size - pos - 1);
> + if (len > 0) {
> + pos += (size_t) len;
> + response[pos] = 0;
> +
> + if ((pos + 1) >= buf_size) {
> + buf_size = buf_size << 1; /* increase response buffer */
> + if (buf_size > (1 << 24)) /* max 16MB */
> + goto error;
> +
> + response = realloc(response, buf_size);
> + if (response == NULL)
> + goto error;
> +
> + memset(&response[pos], 0, buf_size - pos);
> + }
> + } else {
> + if (errno == EAGAIN) {
> + usleep(10000);
> + if (time(NULL) > (start_time + 30)) {
> + libmsg("Error, unable to read metrics"
> + " - timeout after 30s\n");
> + goto error;
> + }
> + } else
> + goto error;
> + }
> + } while ((pos < (size_t) strlen(end_token) ||
> + strcmp(end_token, &response[pos - (size_t) strlen(end_token)]) != 0) &&
> + pos < buf_size);
> +
> + if (fd >= 0)
> + close(fd);
> +
> + return response;
> +
> + error:
> + if (fd >= 0)
> + close(fd);
> + if (response)
> + free(response);
> +
> + return NULL;
> +}
> +
> +/*
> + * dump metrics from virtio serial port to xml formatted file
> + */
> +int dump_virtio_metrics(const char *dest_file)
> +{
> + FILE *fp = stdout;
> + char *response = NULL;
> + size_t len;
> +
> + response = get_virtio_metrics();
> + if (response == NULL)
> + goto error;
> +
> + len = strlen(response);
> +
> + if (dest_file) {
> + fp = fopen(dest_file, "w");
> + if (fp == NULL) {
> + libmsg("Error, unable to dump metrics: fopen(%s) %s\n",
> + dest_file, strerror(errno));
> + goto error;
> + }
> + }
> +
> + if (fwrite(response, 1UL, len, fp) != len) {
> + libmsg("Error, unable to export metrics to file:%s %s\n",
> + dest_file ? dest_file : "stdout", strerror(errno));
> + goto error;
> + }
> +
> + if (response)
> + free(response);
> +
> + return 0;
> +
> + error:
> + if (dest_file && fp)
> + fclose(fp);
> +
> + if (response)
> + free(response);
> +
> + return -1;
> +}
> diff --git a/libmetrics/libmetrics.h b/libmetrics/libmetrics.h
> index 1908de8..c4873ff 100644
> --- a/libmetrics/libmetrics.h
> +++ b/libmetrics/libmetrics.h
> @@ -102,8 +102,4 @@ int dump_xenstore_metrics(const char *dest_file);
>
> /* dump metrics from virtio serial port to xml formatted file */
> int dump_virtio_metrics(const char *dest_file);
> -
> -/* dump metrics from virtio serial port to buffer */
> -const char *get_virtio_metrics(const char *dev_name);
> -
> #endif
> diff --git a/libmetrics/libserialclient.c b/libmetrics/libserialclient.c
> deleted file mode 100644
> index d3a4af5..0000000
> --- a/libmetrics/libserialclient.c
> +++ /dev/null
> @@ -1,172 +0,0 @@
> -/*
> - * Copyright (C) 2018 SAP SE
> - *
> - * 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, write to the Free Software
> - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> - *
> - * Author: Michael Trapp <michael.trapp at sap.com>
> - */
> -
> -#include <config.h>
> -
> -#include <stdio.h>
> -#include <stdlib.h>
> -#include <time.h>
> -#include <string.h>
> -#include <fcntl.h>
> -#include <unistd.h>
> -#include <errno.h>
> -
> -#include "libserialclient.h"
> -
> -
> -/*
> - * dump metrics from virtio serial port to xml formatted file
> - */
> -int dump_virtio_metrics(const char *dest_file)
> -{
> - FILE *fp = stdout;
> - char *response;
> - size_t len;
> -
> - response = get_virtio_metrics(NULL);
> - if (response == NULL)
> - goto error;
> -
> - len = strlen(response);
> -
> - if (dest_file) {
> - fp = fopen(dest_file, "w");
> - if (fp == NULL) {
> - fprintf(stderr,
> - "LIB_SERIALCLIENT: Error, unable to dump metrics: fopen(%s) %s\n",
> - dest_file, strerror(errno));
> - goto error;
> - }
> - }
> -
> - if (fwrite(response, 1UL, len, fp) != len) {
> - fprintf(stderr,
> - "LIB_SERIALCLIENT: Error, unable to export metrics to file:%s - error:%s\n",
> - dest_file ? dest_file : "STDOUT", strerror(errno));
> - goto error;
> - }
> -
> - if (response)
> - free(response);
> -
> - return 0;
> -
> - error:
> - if (dest_file && fp)
> - fclose(fp);
> -
> - if (response)
> - free(response);
> -
> - return -1;
> -}
> -
> -/*
> - * dump metrics from virtio serial port to buffer
> - */
> -char *get_virtio_metrics(const char *dev_name)
> -{
> - const char request[] = "GET /metrics/XML\n\n", end_token[] = "\n\n";
> - const char *dev;
> - char *response = NULL;
> - int fd = -1;
> - size_t pos;
> - size_t buf_size = (1 << 16);
> - const size_t req_len = (size_t) strlen(request);
> - const time_t start_time = time(NULL);
> -
> - if (dev_name)
> - dev = dev_name;
> - else
> - dev = "/dev/virtio-ports/org.github.vhostmd.1";
> -
> - response = calloc(1UL, buf_size);
> - if (response == NULL)
> - goto error;
> -
> - fd = open(dev, O_RDWR | O_NONBLOCK);
> -
> - if (fd < 0) {
> - fprintf(stderr,
> - "LIB_SERIALCLIENT: Error, unable to dump metrics: open(%s) %s\n",
> - dev, strerror(errno));
> - goto error;
> - }
> -
> - pos = 0;
> - while (pos < req_len) {
> - ssize_t len = write(fd, &request[pos], req_len - pos);
> - if (len > 0)
> - pos += (size_t) len;
> - else {
> - if (errno == EAGAIN)
> - usleep(10000);
> - else
> - goto error;
> - }
> - }
> -
> - pos = 0;
> - do {
> - ssize_t len = read(fd, &response[pos], buf_size - pos - 1);
> - if (len > 0) {
> - pos += (size_t) len;
> - response[pos] = 0;
> -
> - if ((pos + 1) >= buf_size) {
> - buf_size = buf_size << 1; /* increase response buffer */
> - if (buf_size > (1 << 24)) /* max 16MB */
> - goto error;
> -
> - response = realloc(response, buf_size);
> - if (response == NULL)
> - goto error;
> -
> - memset(&response[pos], 0, buf_size - pos);
> - }
> - } else {
> - if (errno == EAGAIN) {
> - usleep(10000);
> - if (time(NULL) > (start_time + 30)) {
> - fprintf(stderr,
> - "LIB_SERIALCLIENT: Error, unable to read metrics"
> - " - timeout after 30s\n");
> - goto error;
> - }
> - } else
> - goto error;
> - }
> - } while ((pos < (size_t) strlen(end_token) ||
> - strcmp(end_token, &response[pos - (size_t) strlen(end_token)]) != 0) &&
> - pos < buf_size);
> -
> - if (fd >= 0)
> - close(fd);
> -
> - return response;
> -
> - error:
> - if (fd >= 0)
> - close(fd);
> - if (response)
> - free(response);
> -
> - return NULL;
> -}
> diff --git a/libmetrics/libserialclient.h b/libmetrics/libserialclient.h
> deleted file mode 100644
> index 887c6a5..0000000
> --- a/libmetrics/libserialclient.h
> +++ /dev/null
> @@ -1,30 +0,0 @@
> -/*
> - * Copyright (C) 2018 SAP SE
> - *
> - * 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, write to the Free Software
> - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> - *
> - * Author: Michael Trapp <michael.trapp at sap.com>
> - */
> -
> -#ifndef __LIBSERIALCLIENT_H__
> -#define __LIBSERIALCLIENT_H__
> -
> -/* dump metrics from virtio serial port to xml formatted file */
> -int dump_virtio_metrics(const char *dest_file);
> -
> -/* dump metrics from virtio serial port to buffer */
> -char *get_virtio_metrics(const char *dev_name);
> -
> -#endif
>
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