[slominskir-coding-agent]

What changed

A new page, /disconnected-pvs, linked from the overview page under "Reports". It's for people such as IOC maintainers. It lists the same PVs as /healthcheck: PVs disconnected or never connected for longer than HEALTHCHECK_GRACE_SECONDS, plus frozen PVs. For each PV it shows:

• Clients, from the WebSocket session data (clientName, IP). epics2web.js sends the page address as clientName by default, and WEDM doesn't override it. So a WEDM screen is shown by its edl value and linked to the screen. Sessions with the same name are grouped (×N). Only http/https names become links, and all output is escaped.
• IOC, which the browser looks up in MYA through myquery's GET /channel?q=<pv>&l=50&m=<deployment>. q is a SQL LIKE pattern, so only the exact name match is kept. The IOC column fills in after the page loads, with four lookups at a time. active=false shows as "no longer archived". PVs with no IOC are grouped as "Not archived", "Archived without an IOC" or "Lookup failed".
• Via, the server CAJ last connected the channel to, which at JLab is usually the CA gateway. ChannelMonitor now records channel.getTransport().getRemoteAddress() on each connect. This runs on the callbackExecutor, not inside a CAJ callback. The report shows it as host:port, with reverse DNS cached in ServerNames.

The page has four sections: Summary counts, By IOC (built in JS once the lookups finish), By Client, and PVs.

The healthcheck's PV selection moves to UnhealthyPvs, so both pages list the same PVs. /healthcheck now lists them sorted by name instead of in HashMap order. Its JSON fields and status codes are otherwise unchanged.

New settings (in the README under Healthcheck → "Disconnected PVs report")

Variable	Default	Meaning
MYQUERY_URL	/myquery	Where the browser sends lookups. The default is a relative path, so it reaches myquery on the same proxy host (epicsweb.jlab.org/myquery). Empty turns the lookup off.
MYQUERY_DEPLOYMENT	ops	MYA deployment (myquery's m).

Deployment

None if the defaults suit the ops fiefdom. Question for the reviewer: should other fiefdoms (chl, srf, …) set MYQUERY_DEPLOYMENT, if their PVs are archived in another MYA deployment?

Checks

• ./gradlew spotlessCheck test: passed, 81 unit tests (19 of them new: UnhealthyPvsTest, ClientLabelTest, DisconnectedPvReportTest, plus additions to ApplicationTest).
• ./gradlew integrationTest: passed, 25 tests (22 existing + 3 new). The image was built with the repo Dockerfile (docker compose -f build.yaml build --build-arg CUSTOM_CRT_URL=). The new DisconnectedPvsTest checks three things:
  • the overview links to the report
  • a WEDM clientName is shown and linked by its EDL, and a hostile name is escaped
  • stopping softioc lists channel1 with a …:5064 Via
• In an earlier session, the page was checked by hand in headless Chromium against a stub myquery:
  • only the exact name is kept when another PV also matches the pattern
  • inactive, null-IOC and HTTP 500 lookups
  • the By IOC grouping
  • MYQUERY_URL=""
  • the empty state
  • the minified JS

Not verified

• Real myquery/MYA weren't reachable. Still to check at JLab:
  • the same-origin path through the epicsweb proxy
  • what ioc values look like
  • how long lookups take in a large outage (one request per PV)
• Reverse DNS for Via showed IPs in Docker; at JLab it should show gateway host names.
• No real WEDM session was tried; the URL format comes from WEDM's source (screen.js).

Decisions

• Gateways are almost always used, so Via usually names the gateway. The IOC therefore comes from an outside lookup, and myquery/MYA is the source available now. JLab doesn't use ChannelFinder.
• The lookup runs in the browser, not in epics2web. This keeps epics2web from making new outbound calls, keeps a slow myquery from tying up its threads, and lets the page show at once while the IOC column fills in.
• There's no JSON variant: the report is only for people to read.
• Times are formatted in Java, not with fmt:formatDate. JSTL falls back to Date.toString() when a request has no Accept-Language, and the JS compares the time strings to find the earliest.
• Left for later: a CED web service lookup, or wioc or an EPICS name server, as further sources. Each would be another lookup function in disconnected-pvs.js, tried when the first finds nothing.

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