RTFM · Medical healthchecks
lb.saphira.dicom.wado: retrieve an object over HTTP (WADO-RS)
QIDO asks: WADO delivers. This check retrieves an actual object and demands the one thing a healthy WADO-RS service must return: HTTP 200 with application/dicom. A different verb, a different capability, a different check.
What it proves
The WADO-RS retrieve path: a configured instance/study URL returns 200 with content type application/dicom. This exercises the archive's object store: the part of the system a query check never touches. Continuous-safe, read-only.
How it works
curl issues a GET with Accept: application/dicom to the configured full instance URL; the status line and Content-Type header are both verified. TLS verification follows the same opt-in knob as the rest of the DICOMweb family.
Configuration
| Variable / positional | Default | Meaning |
|---|---|---|
| $6 or LB_SAPHIRA_DICOM_WADO_URL | (required) | Full WADO instance URL |
| LB_SAPHIRA_DICOMWEB_TLS_VERIFY | 0 | 1 = enforce certificate verification |
| LB_SAPHIRA_TIMEOUT | 3 | Transaction deadline |
Point it at a permanent, synthetic test object the archive keeps (stored once by the health-check SCP): retrieval then proves the object store without ever touching patient data.
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.wado"Run it by hand
LB_SAPHIRA_DICOM_WADO_URL='https://pacs/dicomweb/aets/ACPACS/studies/…/series/…/instances/…' \
/var/lib/lb/saphira/lb.saphira.dicom.wado pacs 8081 192.168.20.23 8081
echo $?
# 0 = 200 + application/dicom
# 1 = non-200, wrong content type, or connection failure
# 2 = no URL configuredFailure modes
- 404 on a permanent object: the object store lost the test object: exactly the storage-layer regression this check watches for
- Wrong content type: an HTML login page or error handler answered: a proxy is in the way
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