Merge pull request #921 from hapifhir/health-check

Standalone Java Health Check & Hibernate Dialect Override Fix

Dockerfile

@@ -15,6 +15,9 @@ FROM build-hapi AS build-distroless
 RUN mvn package -DskipTests spring-boot:repackage -Pboot
 RUN mkdir /app && cp /tmp/hapi-fhir-jpaserver-starter/target/ROOT.war /app/main.war
 
+COPY src/main/java/HealthCheck.java /app/HealthCheck.java
+RUN javac /app/HealthCheck.java
+
 
 ########### Use the official Tomcat image as base image for the Tomcat variant
 ########### it can be built using eg. `docker build --target tomcat .`

README.md

@@ -475,6 +475,20 @@ jpa:
     # Then comment all hibernate.search.backend.*
 ```
 
+## Docker Health Check
+
+The distroless Docker image includes a built-in health check that verifies the FHIR server is operational by calling the `/fhir/metadata` endpoint and confirming a valid `CapabilityStatement` is returned. It uses a standalone Java class with no external dependencies, making it compatible with the distroless base image which has no shell or utilities like `curl`.
+
+To run the health check inside a running container:
+
+```
+docker exec hapi-fhir-jpaserver-start java -cp /app HealthCheck
+```
+
+An exit code of `0` indicates the server is healthy. An exit code of `1` indicates a failure, with diagnostic details written to stderr.
+
+To enable periodic health checks, uncomment the `healthcheck` block in `docker-compose.yml`.
+
 ## Running hapi-fhir-jpaserver directly from IntelliJ as Spring Boot
 Make sure you run with the maven profile called ```boot``` and NOT also ```jetty```. Then you are ready to press debug the project directly without any extra Application Servers.
 

docker-compose.yml

@@ -8,9 +8,17 @@ services:
       SPRING_DATASOURCE_USERNAME: "admin"
       SPRING_DATASOURCE_PASSWORD: "admin"
       SPRING_DATASOURCE_DRIVER_CLASS_NAME: "org.postgresql.Driver"
-      SPRING_JPA_PROPERTIES_HIBERNATE_DIALECT: ca.uhn.fhir.jpa.model.dialect.HapiFhirPostgresDialect
+      HIBERNATE_DIALECT: ca.uhn.fhir.jpa.model.dialect.HapiFhirPostgresDialect
     ports:
       - "8080:8080"
+    # Uncomment to enable periodic health checks.
+    # Can also be run manually: docker exec hapi-fhir-jpaserver-start java -cp /app HealthCheck
+    # healthcheck:
+    #   test: ["CMD", "java", "-cp", "/app", "HealthCheck"]
+    #   interval: 30s
+    #   timeout: 10s
+    #   start_period: 60s
+    #   retries: 3
     depends_on:
       hapi-fhir-postgres:
         condition: service_healthy

src/main/java/HealthCheck.java

@@ -0,0 +1,45 @@
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.util.regex.Pattern;
+
+public class HealthCheck {
+
+	public static void main(String[] args) {
+		try {
+			var port = System.getenv().getOrDefault("SERVER_PORT", "8080");
+			var url = new URL("http://localhost:" + port + "/fhir/metadata");
+			var conn = (HttpURLConnection) url.openConnection();
+			conn.setRequestMethod("GET");
+			conn.setRequestProperty("Accept", "application/fhir+json");
+			conn.setConnectTimeout(10000);
+			conn.setReadTimeout(10000);
+
+			var status = conn.getResponseCode();
+			if (status != 200) {
+				System.err.println("Health check failed: HTTP " + status);
+				System.exit(1);
+			}
+
+			var body = new StringBuilder();
+			try (var reader = new BufferedReader(new InputStreamReader(conn.getInputStream()))) {
+				String line;
+				while ((line = reader.readLine()) != null) {
+					body.append(line);
+				}
+			}
+
+			var pattern = Pattern.compile("\"resourceType\"\\s*:\\s*\"CapabilityStatement\"");
+			if (pattern.matcher(body.toString()).find()) {
+				System.exit(0);
+			} else {
+				System.err.println("Health check failed: CapabilityStatement not found in response");
+				System.exit(1);
+			}
+		} catch (Exception e) {
+			System.err.println("Health check failed: " + e.getMessage());
+			System.exit(1);
+		}
+	}
+}

src/main/resources/application.yaml

@@ -120,7 +120,7 @@ spring:
         # Hibernate dialect is auto-detected except for H2/Postgres.
         # If using H2:     ca.uhn.fhir.jpa.model.dialect.HapiFhirH2Dialect
         # If using Postgres: ca.uhn.fhir.jpa.model.dialect.HapiFhirPostgresDialect
-        dialect: ca.uhn.fhir.jpa.model.dialect.HapiFhirH2Dialect
+        dialect: ${HIBERNATE_DIALECT:ca.uhn.fhir.jpa.model.dialect.HapiFhirH2Dialect}
 
         # --- Optional Hibernate DDL & tuning (commented out from source) ---
         hbm2ddl: