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[libvirt] [PATCH v3 08/18] blockjob: add new --raw flag to virsh blockjob



The current output of 'blockjob [--info]' is a single line
designed for human consumption; it's not very nice for machine
parsing.  Furthermore, I have plans to modify the line in
response to the new flag for controlling bandwidth units.
Solve that by adding a --raw parameter, which outputs
information closer to the C struct.

$ virsh blockjob testvm1 vda --raw
 type=Block Copy
 bandwidth=1
 cur=197120
 end=197120

The information is indented, because I'd like for a later patch
to add a mode that iterates over all the vm's disks with status
for each; in that mode, each block name would be listed unindented
before information (if any) about that block.

Now that we have a raw mode, we can guarantee that it won't change
format over time.  Any app that cares about parsing the output can
try --raw, and if it fails, know that it was talking to an older
virsh and fall back to parsing the human-readable format which had
not changed until now; meanwhile, when not using --raw, we have
freed future virsh to change the output to whatever makes sense.

My first change to human mode: this command now guarantees a line
is printed on successful use of the API, even when the API did
not find a current block job (consistent with the rest of virsh).

Bonus: https://bugzilla.redhat.com/show_bug.cgi?id=1135441
complained that this message was confusing:

$ virsh blockjob test1 hda  --async --bandwidth 10
error: conflict between --abort, --info, and --bandwidth modes

even though the man page already documents that --async implies
abort mode, all because '--abort' wasn't present in the command
line.  Since I'm adding another case where options are tied
to or imply a mode, I changed that error to:

error: conflict between abort, info, and bandwidth modes

* tools/virsh-domain.c (cmdBlockJob): Add --raw parameter; tweak
error wording.
* tools/virsh.pod (blockjob): Document it.

Signed-off-by: Eric Blake <eblake redhat com>
---
 tools/virsh-domain.c | 31 +++++++++++++++++++++++--------
 tools/virsh.pod      | 19 ++++++++++++-------
 2 files changed, 35 insertions(+), 15 deletions(-)

diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
index d1297ad..b95e971 100644
--- a/tools/virsh-domain.c
+++ b/tools/virsh-domain.c
@@ -2038,16 +2038,20 @@ static const vshCmdOptDef opts_block_job[] = {
     },
     {.name = "async",
      .type = VSH_OT_BOOL,
-     .help = N_("don't wait for --abort to complete")
+     .help = N_("implies --abort; request but don't wait for job end")
     },
     {.name = "pivot",
      .type = VSH_OT_BOOL,
-     .help = N_("conclude and pivot a copy job")
+     .help = N_("implies --abort; conclude and pivot a copy job")
     },
     {.name = "info",
      .type = VSH_OT_BOOL,
      .help = N_("get active job information for the specified disk")
     },
+    {.name = "raw",
+     .type = VSH_OT_BOOL,
+     .help = N_("implies --info; output details rather than human summary")
+    },
     {.name = "bandwidth",
      .type = VSH_OT_DATA,
      .help = N_("set the Bandwidth limit in MiB/s")
@@ -2077,10 +2081,11 @@ cmdBlockJob(vshControl *ctl, const vshCmd *cmd)
     virDomainBlockJobInfo info;
     bool ret = false;
     int rc;
+    bool raw = vshCommandOptBool(cmd, "raw");
     bool abortMode = (vshCommandOptBool(cmd, "abort") ||
                       vshCommandOptBool(cmd, "async") ||
                       vshCommandOptBool(cmd, "pivot"));
-    bool infoMode = vshCommandOptBool(cmd, "info");
+    bool infoMode = vshCommandOptBool(cmd, "info") || raw;
     bool bandwidth = vshCommandOptBool(cmd, "bandwidth");
     virDomainPtr dom = NULL;
     const char *path;
@@ -2088,7 +2093,7 @@ cmdBlockJob(vshControl *ctl, const vshCmd *cmd)

     if (abortMode + infoMode + bandwidth > 1) {
         vshError(ctl, "%s",
-                 _("conflict between --abort, --info, and --bandwidth modes"));
+                 _("conflict between abort, info, and bandwidth modes"));
         return false;
     }

@@ -2109,14 +2114,24 @@ cmdBlockJob(vshControl *ctl, const vshCmd *cmd)
     if (rc < 0)
         goto cleanup;
     if (rc == 0) {
+        if (!raw)
+            vshPrint(ctl, _("No current block job for %s"), path);
         ret = true;
         goto cleanup;
     }

-    vshPrintJobProgress(vshDomainBlockJobToString(info.type),
-                        info.end - info.cur, info.end);
-    if (info.bandwidth != 0)
-        vshPrint(ctl, _("    Bandwidth limit: %lu MiB/s\n"), info.bandwidth);
+    if (raw) {
+        vshPrint(ctl, _(" type=%s\n bandwidth=%lu\n cur=%llu\n end=%llu\n"),
+                 vshDomainBlockJobTypeToString(info.type),
+                 info.bandwidth, info.cur, info.end);
+    } else {
+        vshPrintJobProgress(vshDomainBlockJobToString(info.type),
+                            info.end - info.cur, info.end);
+        if (info.bandwidth != 0)
+            vshPrint(ctl, _("    Bandwidth limit: %lu MiB/s"),
+                     info.bandwidth);
+        vshPrint(ctl, "\n");
+    }
     ret = true;
  cleanup:
     if (dom)
diff --git a/tools/virsh.pod b/tools/virsh.pod
index ea9267e..3f1bf7e 100644
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -1013,24 +1013,29 @@ exclusive. If no flag is specified, behavior is different depending
 on hypervisor.

 =item B<blockjob> I<domain> I<path> { [I<--abort>] [I<--async>] [I<--pivot>] |
-[I<--info>] | [I<bandwidth>] }
+[I<--info>] [I<--raw>] | [I<bandwidth>] }

-Manage active block operations.  There are three modes: I<--info>,
-I<bandwidth>, and I<--abort>; I<--info> is default except that I<--async>
-or I<--pivot> implies I<--abort>.
+Manage active block operations.  There are three mutually-exclusive  modes:
+I<--info>, I<bandwidth>, and I<--abort>.  I<--async> and I<--pivot> imply
+abort mode; I<--raw> implies info mode; and if no mode was given, I<--info>
+mode is assumed.

 I<path> specifies fully-qualified path of the disk; it 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).

-If I<--abort> is specified, the active job on the specified disk will
+In I<--abort> mode, the active job on the specified disk will
 be aborted.  If I<--async> is also specified, this command will return
 immediately, rather than waiting for the cancellation to complete.  If
 I<--pivot> is specified, this requests that an active copy or active
 commit job be pivoted over to the new image.
-If I<--info> is specified, the active job information on the specified
-disk will be printed.
+
+In I<--info> mode, the active job information on the specified
+disk will be printed.  By default, the output is a single human-readable
+summary line; this format may change in future versions.  Adding
+I<--raw> lists each field of the struct, in a stable format.
+
 I<bandwidth> can be used to set bandwidth limit for the active job.
 Specifying a negative value is interpreted as an unsigned long long
 value or essentially unlimited. The hypervisor can choose whether to
-- 
1.9.3


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