[libvirt] [PATCH v5] virsh: Add more human-friendly output of domblkstat command

Peter Krempa pkrempa at redhat.com
Mon Sep 12 14:27:06 UTC 2011


Users of virsh complain that output of the domblkstat command
is not intuitive enough. This patch adds explanation of fields
returned by this command to the help section for domblkstat and
the man page of virsh. Also a switch --human is added for
domblkstat that prints the fields with more descriptive
texts.

This patch also fixes "error: unknown procedure: 243" while
communicating with an old libvirtd.

https://bugzilla.redhat.com/show_bug.cgi?id=731656

Changes to v4:
- Fields are printed in order established by previous versions
- Fix translation macros
- Run old api unconditionaly (while comunicating with old libvirtd
  "error: unknown procedure: 243" occured)
- Remove redundant field description from command help and add reference
  to man page.
- Fix formating (unnecessary space after function name)
- Fix man page, mentioning that fields may be missig.

Changes to v3:
- Add units to duration values
- Add missing write doc/stranslation
- Add translation from new api names to legacy names used in previous
  versions in virsh

Changes to v2:
- Modify for new fields in virDomainBlockStatsFlags

Changes to v1:
- Rebase to current head
---
 tools/virsh.c   |  234 +++++++++++++++++++++++++++++++++++++++++++------------
 tools/virsh.pod |   20 +++++-
 2 files changed, 204 insertions(+), 50 deletions(-)

diff --git a/tools/virsh.c b/tools/virsh.c
index 3b060bf..766c9be 100644
--- a/tools/virsh.c
+++ b/tools/virsh.c
@@ -369,6 +369,8 @@ static const char *vshDomainStateReasonToString(int state, int reason);
 static const char *vshDomainControlStateToString(int state);
 static const char *vshDomainVcpuStateToString(int state);
 static bool vshConnectionUsability(vshControl *ctl, virConnectPtr conn);
+static virTypedParameterPtr vshFindTypedParamByName(const char *name, virTypedParameterPtr list, int count);
+static char *vshGetTypedParamValue(vshControl *ctl, virTypedParameterPtr item);

 static char *editWriteToTempFile (vshControl *ctl, const char *doc);
 static int   editFile (vshControl *ctl, const char *filename);
@@ -1054,16 +1056,37 @@ cleanup:
  */
 static const vshCmdInfo info_domblkstat[] = {
     {"help", N_("get device block stats for a domain")},
-    {"desc", N_("Get device block stats for a running domain.")},
+    {"desc", N_("Get device block stats for a running domain. See man page or use --human for explanation of fields\n\n")},
     {NULL,NULL}
 };

 static const vshCmdOptDef opts_domblkstat[] = {
     {"domain", VSH_OT_DATA, VSH_OFLAG_REQ, N_("domain name, id or uuid")},
     {"device", VSH_OT_DATA, VSH_OFLAG_REQ, N_("block device")},
+    {"human",  VSH_OT_BOOL, 0, N_("print a more human readable output")},
     {NULL, 0, 0, NULL}
 };

+struct _domblkstat_sequence {
+    const char *field;  /* field name */
+    const char *legacy; /* legacy name from previous releases */
+    const char *human;  /* human-friendly explanation */
+};
+
+/* sequence of values for output to honor legacy format from previous versions */
+static const struct _domblkstat_sequence domblkstat_output[] = {
+    { VIR_DOMAIN_BLOCK_STATS_READ_REQ,          "rd_req", N_("number of read operations:     ") }, /* 0 */
+    { VIR_DOMAIN_BLOCK_STATS_READ_BYTES,        NULL,     N_("number of read bytes:          ") }, /* 1 */
+    { VIR_DOMAIN_BLOCK_STATS_WRITE_REQ,         "wr_req", N_("number of write operations:    ") }, /* 2 */
+    { VIR_DOMAIN_BLOCK_STATS_WRITE_BYTES,       NULL,     N_("number of bytes written:       ") }, /* 3 */
+    { VIR_DOMAIN_BLOCK_STATS_ERRS,              NULL,     N_("error count:                   ") }, /* 4 */
+    { VIR_DOMAIN_BLOCK_STATS_FLUSH_REQ,         NULL,     N_("number of flush operations:    ") }, /* 5 */
+    { VIR_DOMAIN_BLOCK_STATS_READ_TOTAL_TIMES,  NULL,     N_("total duration of reads (ns):  ") }, /* 6 */
+    { VIR_DOMAIN_BLOCK_STATS_WRITE_TOTAL_TIMES, NULL,     N_("total duration of writes (ns): ") }, /* 7 */
+    { VIR_DOMAIN_BLOCK_STATS_FLUSH_TOTAL_TIMES, NULL,     N_("total duration of flushes (ns):") }, /* 8 */
+    { NULL, NULL, NULL }
+};
+
 static bool
 cmdDomblkstat (vshControl *ctl, const vshCmd *cmd)
 {
@@ -1071,8 +1094,13 @@ cmdDomblkstat (vshControl *ctl, const vshCmd *cmd)
     const char *name = NULL, *device = NULL;
     struct _virDomainBlockStats stats;
     virTypedParameterPtr params = NULL;
+    virTypedParameterPtr par = NULL;
+    char *value = NULL;
+    const char *field = NULL;
     int rc, nparams = 0;
+    int i = 0;
     bool ret = false;
+    bool human = vshCommandOptBool(cmd, "human"); /* enable human readable output */

     if (!vshConnectionUsability (ctl, ctl->conn))
         return false;
@@ -1090,76 +1118,105 @@ cmdDomblkstat (vshControl *ctl, const vshCmd *cmd)
      * then.
      */
     if (rc < 0) {
-        if (last_error->code != VIR_ERR_NO_SUPPORT) {
-            virshReportError(ctl);
+        /* try the older api, if the newer returns an error */
+        virFreeError(last_error);
+        last_error = NULL;
+
+        if (virDomainBlockStats (dom, device, &stats,
+                                 sizeof stats) == -1) {
+            vshError(ctl, _("Failed to get block stats %s %s"),
+                     name, device);
             goto cleanup;
-        } else {
-            virFreeError(last_error);
-            last_error = NULL;
+        }

-            if (virDomainBlockStats (dom, device, &stats,
-                                     sizeof stats) == -1) {
-                vshError(ctl, _("Failed to get block stats %s %s"),
-                         name, device);
-                goto cleanup;
-            }
+        if (human) {
+            /* human friendly output */
+            vshPrint(ctl, N_("Device: %s\n"), device);

             if (stats.rd_req >= 0)
-                vshPrint (ctl, "%s rd_req %lld\n", device, stats.rd_req);
+                vshPrint(ctl, "%s %lld\n", _(domblkstat_output[0].human), stats.rd_req);

             if (stats.rd_bytes >= 0)
-                vshPrint (ctl, "%s rd_bytes %lld\n", device, stats.rd_bytes);
+                vshPrint(ctl, "%s %lld\n", _(domblkstat_output[1].human), stats.rd_bytes);

             if (stats.wr_req >= 0)
-                vshPrint (ctl, "%s wr_req %lld\n", device, stats.wr_req);
+                vshPrint(ctl, "%s %lld\n", _(domblkstat_output[2].human), stats.wr_req);

             if (stats.wr_bytes >= 0)
-                vshPrint (ctl, "%s wr_bytes %lld\n", device, stats.wr_bytes);
+                vshPrint(ctl, "%s %lld\n", _(domblkstat_output[3].human), stats.wr_bytes);

             if (stats.errs >= 0)
-                vshPrint (ctl, "%s errs %lld\n", device, stats.errs);
+                vshPrint(ctl, "%s %lld\n", _(domblkstat_output[4].human), stats.errs);
+        } else {
+
+            if (stats.rd_req >= 0)
+                vshPrint(ctl, "%s rd_req %lld\n", device, stats.rd_req);
+
+            if (stats.rd_bytes >= 0)
+                vshPrint(ctl, "%s rd_bytes %lld\n", device, stats.rd_bytes);
+
+            if (stats.wr_req >= 0)
+                vshPrint(ctl, "%s wr_req %lld\n", device, stats.wr_req);
+
+            if (stats.wr_bytes >= 0)
+                vshPrint(ctl, "%s wr_bytes %lld\n", device, stats.wr_bytes);
+
+            if (stats.errs >= 0)
+                vshPrint(ctl, "%s errs %lld\n", device, stats.errs);
         }
     } else {
-        params = vshMalloc(ctl, sizeof(*params) * nparams);
-        memset(params, 0, sizeof(*params) * nparams);
+        params = vshCalloc(ctl, nparams, sizeof(*params));

         if (virDomainBlockStatsFlags (dom, device, params, &nparams, 0) < 0) {
             vshError(ctl, _("Failed to get block stats %s %s"), name, device);
             goto cleanup;
         }

-        int i;
-        /* XXX: The output sequence will be different. */
+        /* set for prettier output */
+        if (human) {
+            vshPrint(ctl, N_("Device: %s\n"), device);
+            device = "";
+        }
+
+        /* at first print all known values in desired order */
+        for (i = 0; domblkstat_output[i].field != NULL; i++) {
+            if (!(par = vshFindTypedParamByName(domblkstat_output[i].field,
+                                          params,
+                                          nparams)))
+                continue;
+
+            if (!(value = vshGetTypedParamValue(ctl, par)))
+                continue;
+
+            /* to print other not supported fields, mark the already printed */
+            par->field[0] = '\0'; /* set the name to empty string */
+
+            /* print the value */
+            field = NULL;
+
+            if (human)
+                field = _(domblkstat_output[i].human);
+            else
+                field = domblkstat_output[i].legacy;
+
+            if (!field)
+                field = domblkstat_output[i].field;
+
+            vshPrint(ctl, "%s %s %s\n", device, field, value);
+
+            VIR_FREE(value);
+        }
+
+        /* go through the fields again, looking for fields that were not printed*/
         for (i = 0; i < nparams; i++) {
-            switch(params[i].type) {
-            case VIR_TYPED_PARAM_INT:
-                vshPrint (ctl, "%s %s %d\n", device,
-                          params[i].field, params[i].value.i);
-                break;
-            case VIR_TYPED_PARAM_UINT:
-                vshPrint (ctl, "%s %s %u\n", device,
-                          params[i].field, params[i].value.ui);
-                break;
-            case VIR_TYPED_PARAM_LLONG:
-                vshPrint (ctl, "%s %s %lld\n", device,
-                          params[i].field, params[i].value.l);
-                break;
-            case VIR_TYPED_PARAM_ULLONG:
-                vshPrint (ctl, "%s %s %llu\n", device,
-                          params[i].field, params[i].value.ul);
-                break;
-            case VIR_TYPED_PARAM_DOUBLE:
-                vshPrint (ctl, "%s %s %f\n", device,
-                          params[i].field, params[i].value.d);
-                break;
-            case VIR_TYPED_PARAM_BOOLEAN:
-                vshPrint (ctl, "%s %s %s\n", device,
-                          params[i].field, params[i].value.b ? _("yes") : _("no"));
-                break;
-            default:
-                vshError(ctl, _("unimplemented block statistics parameter type"));
-            }
+            if (strlen(params[i].field) == 0)
+                continue;

+            if (!(value = vshGetTypedParamValue(ctl, params+i)))
+                continue;
+
+            vshPrint(ctl, "%s %s %s\n", device, params[i].field, value);
+            VIR_FREE(value);
         }
     }

@@ -15185,6 +15242,85 @@ vshDomainStateReasonToString(int state, int reason)
     return N_("unknown");
 }

+static char *
+vshGetTypedParamValue(vshControl *ctl, virTypedParameterPtr item)
+{
+    int size = 0;
+    char *str = NULL;
+
+    if (!ctl || !item)
+        return NULL;
+
+    switch(item->type) {
+    case VIR_TYPED_PARAM_INT:
+        size = snprintf(NULL, 0, "%d", item->value.i);
+        str = vshMalloc(ctl, size+1);
+        snprintf(str, size+1, "%d", item->value.i);
+        return str;
+        break;
+
+    case VIR_TYPED_PARAM_UINT:
+        size = snprintf(NULL, 0, "%u", item->value.ui);
+        str = vshMalloc(ctl, size+1);
+        snprintf(str, size+1, "%u", item->value.ui);
+        return str;
+        break;
+
+    case VIR_TYPED_PARAM_LLONG:
+         size = snprintf(NULL, 0, "%lld", item->value.l);
+        str = vshMalloc(ctl, size+1);
+        snprintf(str, size+1, "%lld", item->value.l);
+        return str;
+        break;
+
+    case VIR_TYPED_PARAM_ULLONG:
+        size = snprintf(NULL, 0, "%llu", item->value.ul);
+        str = vshMalloc(ctl, size+1);
+        snprintf(str, size+1, "%llu", item->value.ul);
+        return str;
+        break;
+
+    case VIR_TYPED_PARAM_DOUBLE:
+        size = snprintf(NULL, 0, "%f", item->value.d);
+        str = vshMalloc(ctl, size+1);
+        snprintf(str, size+1, "%f", item->value.d);
+        return str;
+        break;
+
+    case VIR_TYPED_PARAM_BOOLEAN:
+        size = snprintf(NULL, 0, "%s", item->value.b ? _("yes") : _("no"));
+        str = vshMalloc(ctl, size+1);
+        snprintf(str, size+1, "%s", item->value.b ? _("yes") : _("no"));
+        return str;
+        break;
+
+    default:
+        vshError(ctl, _("unimplemented block statistics parameter type"));
+    }
+
+    return NULL;
+}
+
+static virTypedParameterPtr
+vshFindTypedParamByName(const char *name, virTypedParameterPtr list, int count)
+{
+    int i = count;
+    virTypedParameterPtr found = list;
+
+    if (!list || !name)
+        return NULL;
+
+    while (i-- > 0) {
+        if (STREQ(name, found->field))
+            return found;
+
+        found++; /* go to next struct in array */
+    }
+
+    /* not found */
+    return NULL;
+}
+
 static const char *
 vshDomainControlStateToString(int state)
 {
diff --git a/tools/virsh.pod b/tools/virsh.pod
index e82567d..519e60b 100644
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -501,13 +501,31 @@ be lost once the guest stops running, but the snapshot contents still
 exist, and a new domain with the same name and UUID can restore the
 snapshot metadata with B<snapshot-create>.

-=item B<domblkstat> I<domain> I<block-device>
+=item B<domblkstat> I<domain> I<block-device> [I<--human>]

 Get device block stats for a running domain.  A I<block-device> corresponds
 to a unique target name (<target dev='name'/>) or source file (<source
 file='name'/>) for one of the disk devices attached to I<domain> (see
 also B<domblklist> for listing these names).

+Use I<--human> for a more human readable output.
+
+Availabilty of these fields depends on hypervisor. Unsupported fields are
+missing from the output. Other fields may appear if comunicating with a newer
+version of libvirtd.
+
+B<Explanation of fields> (fields appear in the folowing order):
+  rd_req            - count of read operations
+  rd_bytes          - count of read bytes
+  wr_req            - count of write operations
+  wr_bytes          - count of written bytes
+  errs              - error count
+  flush_operations  - count of flush operations
+  rd_total_times    - total time read operations took (ns)
+  wr_total_times    - total time write operations took (ns)
+  flush_total_times - total time flush operations took (ns)
+    <-- other fields provided by hypervisor -->
+
 =item B<domifstat> I<domain> I<interface-device>

 Get network interface stats for a running domain.
-- 
1.7.3.4




More information about the libvir-list mailing list