Synchronize betweem VOMS/IAM/CS from VOMS2CSAgent

[chaen]

Edit: I add an extra usecase to this task

The VOMS interface provided by IAM does not actually expose the voms-admin API, which means we need to query the IAM API to list the users.

TODO:

• [ ] Query IAM and expose the info like if it was coming from VOMS for it to be synced in VOMS2CSAgent
• [ ] populate /DiracX/<vo>/UserSubjects

In the VOMS2CSAgent, update the /DiracX/<vo><UserSubjects> section directly from IAM (https://indigo-iam.github.io/v/v1.8.3/docs/reference/api/account-api/#get-iamaccountsearch)

curl -q -L -s  -u ${CLIENT_ID}:${CLIENT_SECRET}  -d grant_type=client_credentials -d scope=iam:admin.read     ${IAM_TOKEN_ENDPOINT} > /tmp/token.json

export AT=$(cat /tmp/token.json  | jq ".access_token")

import requests, json
import os
token = os.environ.get('AT')

headers = {"Authorization": f"Bearer {token}"}
iam_list_url = 'https://lhcb-auth.web.cern.ch/iam/account/search'
results = []
startIndex = 1
totalResults = 1000  # total number of users
itemsPerPage = 10
while(startIndex < totalResults):
    resp = requests.get(iam_list_url, headers=headers, params = {'startIndex':startIndex})
    resp.raise_for_status()
    data = resp.json()
    # These 2 should never change, but just to be sure...
    totalResults = data['totalResults']
    itemsPerPage = data['itemsPerPage']

    startIndex += itemsPerPage
    results.extend(data['Resources'])
with open('accounts.json', 'w+') as fp:
    fp.write(json.dumps(results))

Originally posted by @chaen in https://github.com/DIRACGrid/diracx/issues/191#issuecomment-1904135971

[chaen]

There's another API, probably better, because it only requires scim:read scope

https://indigo-iam.github.io/v/v1.8.3/docs/reference/api/scim-api/#get-scimusers