Use ResourceLoader for keys

Spring's ResourceLoader supports prefixing with `classpath:`. This way
we can use the `resources` directory locally but something else in k8s.

src/main/java/de/bund/digitalservice/a2j/config/FitConnectConfig.java

@@ -11,16 +11,18 @@
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.nio.file.Paths;
 import java.text.ParseException;
 import java.util.List;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
-import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.ResourceLoader;
 
 @Configuration
 public class FitConnectConfig {
+  private final ResourceLoader resourceLoader;
+
   @Value("${fitConnect.sender.clientId}")
   String senderClientId;
 
@@ -39,6 +41,10 @@ public class FitConnectConfig {
   @Value("${fitConnect.subscriber.privateSigningKeyPath}")
   String subscriberPrivateSigningKeyPath;
 
+  public FitConnectConfig(ResourceLoader resourceLoader) {
+    this.resourceLoader = resourceLoader;
+  }
+
   @Bean
   public SenderClient senderClient() {
     SenderConfig senderConfig =
@@ -73,7 +79,8 @@ public SubscriberClient subscriberClient() throws IOException, ParseException {
   }
 
   private JWK loadKey(String filePath) throws IOException, ParseException {
-    Path path = Paths.get(new ClassPathResource(filePath).getURI());
+    Resource resource = resourceLoader.getResource(filePath);
+    Path path = resource.getFile().toPath();
     String jwkContent = Files.readString(path);
 
     return JWK.parse(jwkContent);

src/main/resources/application-local.yaml.example

@@ -5,8 +5,8 @@ fitConnect:
   subscriber:
     clientId: subscriberClientId
     clientSecret: s3cr3t
-    privateDecryptionKeyPath: decryption_key.json
-    privateSigningKeyPath: signing_key.json
+    privateDecryptionKeyPath: classpath:decryption_key.json
+    privateSigningKeyPath: classpath:signing_key.json
   activeEnvironment: TEST
   submission:
     destination: destinationId

src/test/resources/application-test.yaml

@@ -5,8 +5,8 @@ fitConnect:
   subscriber:
     clientId: subscriberClientId
     clientSecret: s3cr3t
-    privateDecryptionKeyPath: decryption_key.json
-    privateSigningKeyPath: signing_key.json
+    privateDecryptionKeyPath: classpath:decryption_key.json
+    privateSigningKeyPath: classpath:signing_key.json
   activeEnvironment: TEST
   submission:
     destination: destinationId