RTFM · Medical healthchecks
lb.saphira.dicom.qido: query the archive over HTTP (QIDO-RS)
DICOMweb is DICOM's modern REST dialect, and QIDO-RS is its search verb. The check queries a real endpoint with a synthetic key and demands the one thing a healthy QIDO service must return: HTTP 200 with application/dicom+json.
What it proves
The QIDO-RS read path end to end: the endpoint answers 200 and the content type is genuinely application/dicom+json; not a generic HTML error page in disguise. Continuous-safe and read-only. Kept separate from WADO and STOW by the package rule: query, retrieve and store are different capabilities and get different checks.
How it works
curl issues a GET with Accept: application/dicom+json to the configured full URL; including the AE-title path and query parameters, because that is what a real DICOMweb client sends. Both the status line and the Content-Type header are verified.
Configuration
| Variable / positional | Default | Meaning |
|---|---|---|
| $6 or LB_SAPHIRA_DICOM_QIDO_URL | (required) | Full QIDO URL incl. aets and query; per-VIP in dicom.qido/<service>.conf |
| LB_SAPHIRA_DICOMWEB_TLS_VERIFY | 0 | 1 = enforce certificate verification |
| LB_SAPHIRA_TIMEOUT | 3 | Transaction deadline |
Wiring it up
# ldirectord.cf - DICOMweb pool
virtual = 203.0.113.10:8081
protocol = tcp
scheduler = wlc
real = 192.168.20.23:8081 gate 1
checktype = external
checkcommand = "/var/lib/lb/saphira/lb.saphira.dicom.qido"# /etc/saphira/lb-healthchecks.d/dicom.qido/pacs.conf
LB_SAPHIRA_DICOM_QIDO_URL=https://pacs.internal/dicomweb/aets/ACPACS/studies?PatientID=SAPHIRA-SYNTHETIC-HEALTHCHECKRun it by hand
LB_SAPHIRA_DICOM_QIDO_URL='https://pacs/dicomweb/aets/ACPACS/studies?PatientID=X' \
/var/lib/lb/saphira/lb.saphira.dicom.qido pacs 8081 192.168.20.23 8081
echo $?
# 0 = 200 + application/dicom+json
# 1 = non-200, wrong content type, or connection failure
# 2 = no URL configuredFailure modes
- 200 with the wrong content type; a proxy or gateway answered instead of the DICOMweb service: the subtle failure this check exists for
- 401/403 under load: auth tiers degrading: visible here, not at the modality
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