Instruction file imported from navikt/sokos-skattekort (.github/instructions/kotlin-ktor.instructions.md). Copyright stays with the author.

Kotlin/Ktor general patterns

Ktor backend service on NAIS (not Rapids & Rivers, not Spring Boot). For tests see testing.instructions.md and the kotest skill.

Configuration

All config access via PropertiesConfig singleton. See the kotlin-app-config skill for full HOCON layering and @Serializable data-class pattern.

val appName = PropertiesConfig.getApplicationProperties().naisAppName

Ktor routing

Health/metrics endpoints are unauthenticated; domain routes sit behind authenticate(AUTHENTICATION_NAME). Expose: /internal/isAlive, /internal/isReady, /internal/metrics.

Logging

• Regular messages → Logback → Grafana Loki.
• Sensitive data (PII, case numbers, request/response bodies, tokens) → must use TEAM_LOGS_MARKER:

logger.error(marker = TEAM_LOGS_MARKER) { "Error for case: $caseId" }

Metrics

Use the Metrics object (Micrometer PrometheusMeterRegistry). Define a namespace constant matching the app name (e.g. sokos_my_app). Register counters via Counter.builder().

Boundaries

✅ Always

• PropertiesConfig for config — never System.getenv() in business logic
• TEAM_LOGS_MARKER for sensitive data

🚫 Never

• Commit defaults.properties
• Log PII/request bodies without TEAM_LOGS_MARKER
• Use !! without a preceding null check