[dm-devel] [PATCH v5 0/1] add option to output JSON for multipathd command

[Christophe Varoqui]

This v5 is merged.
Thanks.

On Tue, May 24, 2016 at 8:03 PM, Todd Gill <tgill at redhat.com> wrote:

> Hi,
>
> I had earlier sent an email to dm-devel proposing we add a feature
> in multipathd to output multipath map topology in JSON format. This
> patch contains to the code for that feature.
>
> Having an option for the  CLI to output in JSON would allow higher
> level applications to more easily monitor/manage multipath.
>
> I thought it was best to take advantage of some of the existing
> snprintf_xxx functions rather than adding a library dependency
> to multipathd.
>
> Any feedback welcome.
>
> v2:
> - added major/minor version fields
> - updates from feedback
> - added path groups
> - changed indent levels to make it easier to read
> - removed quotes from integer fields
> - fixed bug when the JSON string length exceeded the allocated memory
> - removed multipath field from path object - it isn't needed since
>   the path is inside the map
>
> v3:
> - split out vend/prod/rev into seperate fields
> - added new format specifiers for map:
>   %v - vend
>   %p - prod
>   %e - rev
> - removed vend/prod/rev from the path level since it is in the map
>
> v4:
> - removed space from major/minor version fields
>
> v5:
> - add group number at the group level
> - use an underscore to seperate words in the key part of the
> JSON
> - remove hcil, next_check, size, serial fields
> - remove uuid from the path level - it is already in the map
> - change JSON key from dm-st to dm_st
> - make all keys lower case
> - remove unnecessary call to memset - this addresses the performance
> problem.  memset is already called in MALLOC (zalloc)
> - multiply the initial allocation of memory with VECTOR_SIZE(vecs->mpvec)
> to reduce the number of realloc calls.
> - corrected reply + 1 in return of string length, correct length is
> c - reply, not c - reply + 1
>
> # multipathd show map dm-4 json
> {
>    "major_version": 0,
>    "minor_version": 1,
>    "map":{
>       "name" : "360a980004236646530244268305a3147",
>       "uuid" : "360a980004236646530244268305a3147",
>       "sysfs" : "dm-4",
>       "failback" : "immediate",
>       "queueing" : "on",
>       "paths" : 2,
>       "write_prot" : "rw",
>       "dm_st" : "active",
>       "features" : "4 queue_if_no_path pg_init_retries 50
> retain_attached_hw_handle",
>       "hwhandler" : "0",
>       "action" : "",
>       "path_faults" : 0,
>       "vend" : "NETAPP",
>       "prod" : "LUN",
>       "rev" : "811a",
>       "switch_grp" : 0,
>       "map_loads" : 1,
>       "total_q_time" : 0,
>       "q_timeouts" : 0,
>       "path_groups": [{
>          "selector" : "service-time 0",
>          "pri" : 50,
>          "dm_st" : "active",
>          "group" : 1,
>          "paths": [{
>             "dev" : "sdi",
>             "dev_t" : "8:128",
>             "dm_st" : "active",
>             "dev_st" : "running",
>             "chk_st" : "ready",
>             "checker" : "tur",
>             "pri" : 50,
>             "host_wwnn" : "0x50014380120d8425",
>             "target_wwnn" : "0x500a098080ba5a64",
>             "host_wwpn" : "0x50014380120d8424",
>             "target_wwpn" : "0x500a098180ba5a64",
>             "host_adapter" : "0000:00:03.0"
>          }]
>       },{
>          "selector" : "service-time 0",
>          "pri" : 10,
>          "dm_st" : "enabled",
>          "group" : 2,
>          "paths": [{
>             "dev" : "sdp",
>             "dev_t" : "8:240",
>             "dm_st" : "active",
>             "dev_st" : "running",
>             "chk_st" : "ready",
>             "checker" : "tur",
>             "pri" : 10,
>             "host_wwnn" : "0x50014380120d8427",
>             "target_wwnn" : "0x500a098080ba5a64",
>             "host_wwpn" : "0x50014380120d8426",
>             "target_wwpn" : "0x500a098190ba5a64",
>             "host_adapter" : "0000:00:03.0"
>          }]
>       }]
>    }
> }
>
> Todd Gill (1):
>   add display of map information in JSON format
>
>  libmultipath/print.c      | 222
> ++++++++++++++++++++++++++++++++++++++++++++++
>  libmultipath/print.h      |  61 +++++++++++++
>  multipathd/cli.c          |   3 +
>  multipathd/cli.h          |   2 +
>  multipathd/cli_handlers.c |  93 +++++++++++++++++++
>  multipathd/cli_handlers.h |   2 +
>  multipathd/main.c         |   2 +
>  7 files changed, 385 insertions(+)
>
> --
> 2.5.5
>
> --
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>
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