Vidocq Documentation

Knock implements the standard MicroProfile Health 4.0 contract. Application code written against the spec — HealthCheck, HealthCheckResponse, @Liveness/@Readiness/@Startup — ports without change. Migration effort is concentrated in build configuration and in dropping vendor-specific extensions.

From SmallRye Health

SmallRye Knock Note

HealthCheck beans

HealthCheck beans

Identical. Keep your classes as-is.

@Liveness / @Readiness / @Startup

Same annotations

Standard MicroProfile Health. No change.

Vendor JSON extensions / extra fields

Standard JSON only

Knock emits the spec payload exactly (status, checks[], optional data). Drop non-standard fields.

Reactive / Mutiny checks

Synchronous HealthCheck

Knock runs each call() on a virtual thread; no reactive API is exposed.

mp.health.* config knobs

Not applicable

Knock has no vendor configuration surface; behaviour follows the spec.

Migration steps

  1. Replace the SmallRye Health dependency with knock-api, knock-core, knock-cdi-vauban and knock-jaxrs (see Reference).

  2. Ensure each HealthCheck carries exactly one probe qualifier — Knock rejects unqualified checks at deployment time.

  3. Remove any vendor-specific extra data fields if downstream consumers required the strict spec payload.

  4. Add a module-info.java requiring microprofile.health.api (Knock is strict JPMS).

  5. Verify the four endpoints respond and the aggregate HTTP status is 200/503 as expected.

Pitfalls

  • Unqualified checks — a HealthCheck without @Liveness/@Readiness/@Startup fails CDI validation. Add the missing qualifier.

  • Non-standard JSON — consumers relying on vendor fields must be updated; Knock emits only the spec shape.

  • data typing — only String, long, boolean and int are rendered natively; other types are stringified.

  • Module path — missing requires clauses surface as JPMS resolution errors rather than classpath warnings.

Going further