Dear dCache admins,
With a great help of TRIUMF(ATLAS), KIT(ATLAS/CMS), PIC(ATLAS/CMS) and DESY-HH(ATLAS/CMS)
we are please to inform you that with the latest series of stable releases 7.1.9 [1], 7.0.18
[2], 6.2.29 [3], 6.1.35 [4], 6.0.45 [5] and 5.2.51 [6] the new Storage Resource Reporting
(a-ka SRR) functionality is finally available.

The SRR is implemented as a REST-API and integrated into frontend service (only host running
front end can be updated).
[frontendDomain]
[frontendDomain/frontend]
frontend.authn.basic=true
frontend.authn.protocol=http
frontend.authz.anonymous-operations=READONLY
frontend.srr.shares=user:/cms,store:/cms
After domain is up you can get the information with curl as:
$ curl http://localhost:3880/api/v1/srr
NOTE: the access to SRR information is restricted to localhost only. Thus you have to put it somewhere, where from WLCG ops can access it. At DESY we simply copy it into dcache with cron:
*/30 * * * * root rm -f /pnfs/desy.de/cms/SRR/SRR_DESY-HH_CMS.json && \
curl http://localhost:3880/api/v1/srr > /pnfs/desy.de/cms/SRR/SRR_DESY-
HH_CMS.json && \
chown 40751:4075 /pnfs/desy.de/cms/SRR/SRR_DESY-HH_CMS.json

The service produces desired json output which contains `storageshares` that represented by space reservations and pool groups, if configured.
The `frontend.srr.shares` controls which pools groups should be published, for example:

frontend.srr.shares=user:/cms,store:/cms

publishes pool groups user and store for VO cms and will produce output like:

"storageshares" : [ {
"name" : "store",
"timestamp" : 1601977212,
"totalsize" : 5973622320626816,
"usedsize" : 4904609242438918,
"assignedendpoints" : [ "all" ],
"vos" : [ "/cms" ]
}, {
"name" : "user",
"timestamp" : 1601977212,
"totalsize" : 4078599175816242,
"usedsize" : 4025729976567280,
"assignedendpoints" : [ "all" ],
"vos" : [ "/cms" ]
} ]

Again, many thanks to TRIUMF, KIT, PIC and DESY-HH site admins for their
help and support.
On behalf of the dCache team,
Tigran

[1] https://www.dcache.org/downloads/1.9/release-notes-7.1.shtml#release7.1.9
[2] https://www.dcache.org/downloads/1.9/release-notes-7.0.shtml#release7.0.18
[3] https://www.dcache.org/downloads/1.9/release-notes-6.2.shtml#release6.2.29
[4] https://www.dcache.org/downloads/1.9/release-notes-6.1.shtml#release6.1.35
[5] https://www.dcache.org/downloads/1.9/release-notes-6.0.shtml#release6.0.45
[6] https://www.dcache.org/downloads/1.9/release-notes-5.2.shtml#release5.2.51

-- JuliaAndreeva - 2021-11-30