omdb: one ereport pretty-printer to rule them all

[hawkw]

As seen in today's Demo Friday, I have put together a little pretty-printer for formatting ereport JSON in a human-focused way. The format it outputs is a little less full of delimiters than the JSON object, as it's indentation delimited, and should look pretty familiar to anyone who's used fmdump -eV or similar. More importantly, though, giving us a custom formatter gives us opportunities to prettify and enrich specific fields and structures which commonly occur in ereports by convention. Currently, the most interesting example of this is PMBus status registers from ereports that SPs emit about PMBus devices.

For example, let's consider an ereport that I harvested from the dogfood rack's PSC. In the current (JSON) format, it looks like this:

root@oxz_switch1:~# omdb db ereport show e9674d6e-cd4b-0cf3-ee6d-0c062720b868 0x5
note: database URL not specified.  Will search DNS.
note: (override with --db-url or OMDB_DB_URL)
note: using DNS from system config (typically /etc/resolv.conf)
note: (if this is not right, use --dns-server to specify an alternate DNS server)
note: using database URL postgresql://root@[fd00:1122:3344:109::3]:32221,[fd00:1122:3344:105::3]:32221,[fd00:1122:3344:10b::3]:32221,[fd00:1122:3344:107::3]:32221,[fd00:1122:3344:108::3]:32221/omicron?sslmode=disable
note: database schema version matches expected (257.0.0)

== EREPORT METADATA ============================================================
                      ENA: 0x5
                    class: hw.pwr.pwr_good.bad
             collected at: 2025-11-14 20:38:20.177799 UTC
             collected by: 8af5baf2-7611-43fc-817c-283cb25e149f
              reported by: Power 0 (service processor)
               restart ID: e9674d6e-cd4b-0cf3-ee6d-0c062720b868
              part number: 913-0000003
            serial number: BRM45220004
    marked seen in sitrep: None

== EREPORT =====================================================================
{
  "baseboard_part_number": "913-0000003",
  "baseboard_rev": 8,
  "baseboard_serial_number": "BRM45220004",
  "ereport_message_version": 0,
  "fruid": {
    "fw_rev": "0701",
    "mfr": "Murata-PS",
    "mpn": "MWOCP68-3600-D-RM",
    "serial": "LL2216RB003Z"
  },
  "hubris_archive_id": "qSm4IUtvQe0",
  "hubris_task_gen": 0,
  "hubris_task_name": "sequencer",
  "hubris_uptime_ms": 1197408566,
  "k": "hw.pwr.pwr_good.bad",
  "pmbus_status": {
    "cml": 0,
    "input": 48,
    "iout": 0,
    "mfr": 0,
    "temp": 0,
    "vout": 0,
    "word": 10312
  },
  "rail": "V54_PSU4",
  "refdes": "PSU4",
  "slot": 4,
  "v": 0
}
root@oxz_switch1:~#

With the new formatter, it looks like this:

root@oxz_switch1:~# /tmp/omdb-erebor db ereport show e9674d6e-cd4b-0cf3-ee6d-0c062720b868 0x5
note: database URL not specified.  Will search DNS.
note: (override with --db-url or OMDB_DB_URL)
note: using DNS from system config (typically /etc/resolv.conf)
note: (if this is not right, use --dns-server to specify an alternate DNS server)
note: using database URL postgresql://root@[fd00:1122:3344:109::3]:32221,[fd00:1122:3344:105::3]:32221,[fd00:1122:3344:10b::3]:32221,[fd00:1122:3344:107::3]:32221,[fd00:1122:3344:108::3]:32221/omicron?sslmode=disable
WARN: found schema version 257.0.0, expected 261.0.0
It's possible the database is running a version that's different from what this
tool understands.  This may result in errors or incorrect output.

== EREPORT METADATA ============================================================
                      ENA: 0x5
                    class: hw.pwr.pwr_good.bad
             collected at: 2025-11-14 20:38:20.177799 UTC
             collected by: 8af5baf2-7611-43fc-817c-283cb25e149f
              reported by: Power 0 (service processor)
               restart ID: e9674d6e-cd4b-0cf3-ee6d-0c062720b868
              part number: 913-0000003
            serial number: BRM45220004
    marked seen in sitrep: None

== EREPORT =====================================================================
baseboard_part_number = 913-0000003
baseboard_rev = 0x8
baseboard_serial_number = BRM45220004
ereport_message_version = 0x0
fruid = (object)
    fw_rev = 0701
    mfr = Murata-PS
    mpn = MWOCP68-3600-D-RM
    serial = LL2216RB003Z
(end fruid)

hubris_archive_id = qSm4IUtvQe0
hubris_task_gen = 0x0
hubris_task_name = sequencer
hubris_uptime_ms = 1197408566 (1197408.566s)
class = hw.pwr.pwr_good.bad
pmbus_status = (PMBus status)
    STATUS_WORD         = 0x2848 (InputFault | PowerGoodStatus | Off | InputUndervoltageFault)
    STATUS_VOUT         = 0x00
    STATUS_IOUT         = 0x00
    STATUS_INPUT        = 0x30 (InputUndervoltageWarning | InputUndervoltageFault)
    STATUS_TEMPERATURE  = 0x00
    STATUS_CML          = 0x00
    STATUS_MFR_SPECIFIC = 0x00
(end PMBus status)

rail = V54_PSU4
refdes = PSU4
slot = 0x4
version = 0


root@oxz_switch1:~#

Note that Bryan's pmbus crate is used to decode the PMBus status registers, which should allow folks to get a sense for what happened here without having to manually interpret the status register bitflags.

I've put this new formatter in a crate, named erebor --- this is either a portmanteau of "ereport" and "CBOR", or a reference to the Lonely Mountain of Middle-Earth, named "Erebor" in Sindarin; where Smaug destroyed the Dwarves' kingdom in an event that one assumes must have produced a great deal of ereports. This is intended to allow reusing it in omdb, in the faux-mgs ereports command, and perhaps elsewhere, eventually.

This branch adds it to omdb. Since I am sure there are situations where one would want to get the output as JSON, I've also added new --json adn --raw flags for doing that.

[wfchandler]

Thanks! Two small suggestions, but this looks good to me.