feat: gateway integration on BTP (#15)

Author: jurosens

pom.xml

@@ -260,6 +260,11 @@
       <groupId>com.sap.hcp.cf.logging</groupId>
       <artifactId>cf-java-logging-support-logback</artifactId>
     </dependency>
+    <dependency>
+      <groupId>com.nimbusds</groupId>
+      <artifactId>nimbus-jose-jwt</artifactId>
+      <version>9.9.2</version>
+    </dependency>
   </dependencies>
 
   <build>

src/main/java/eu/europa/ec/dgc/businessrule/config/btp/SapCredentialStoreCfEnvProcessor.java

@@ -0,0 +1,68 @@
+package eu.europa.ec.dgc.businessrule.config.btp;
+
+import io.pivotal.cfenv.core.CfCredentials;
+import io.pivotal.cfenv.core.CfService;
+import io.pivotal.cfenv.spring.boot.CfEnvProcessor;
+import io.pivotal.cfenv.spring.boot.CfEnvProcessorProperties;
+import java.util.Map;
+
+/**
+ * Custom implementation of {@link CfEnvProcessor} for reading the SAP credential store parameters from the <code>
+ * VCAP_SERVICES</code> environment variable and making them available as properties in the spring context.
+ * <br/><br/>
+ * The following properties are available in the context after the processor is done:
+ * <code>
+ * <ul>
+ *     <li>sap.btp.credstore.url</li>
+ *     <li>sap.btp.credstore.password</li>
+ *     <li>sap.btp.credstore.username</li>
+ *     <li>sap.btp.credstore.clientPrivateKey</li>
+ *     <li>sap.btp.credstore.serverPublicKey</li>
+ * </ul>
+ * </code>
+ *
+ * @see CfEnvProcessor
+ */
+public class SapCredentialStoreCfEnvProcessor implements CfEnvProcessor {
+
+    private static final String CRED_STORE_SCHEME = "credstore";
+    private static final String CRED_STORE_PROPERTY_PREFIX = "sap.btp.credstore";
+
+    @Override
+    public boolean accept(CfService service) {
+        return service.existsByTagIgnoreCase(CRED_STORE_SCHEME, "securestore", "keystore", "credentials")
+            || service.existsByLabelStartsWith(CRED_STORE_SCHEME)
+            || service.existsByUriSchemeStartsWith(CRED_STORE_SCHEME);
+    }
+
+    @Override
+    public void process(CfCredentials cfCredentials, Map<String, Object> properties) {
+        properties.put(CRED_STORE_PROPERTY_PREFIX + ".url", cfCredentials.getString("url"));
+        properties.put(CRED_STORE_PROPERTY_PREFIX + ".password", cfCredentials.getString("password"));
+        properties.put(CRED_STORE_PROPERTY_PREFIX + ".username", cfCredentials.getString("username"));
+
+        @SuppressWarnings("unchecked")
+        Map<String, Object> encryption = (Map<String, Object>) cfCredentials.getMap().get("encryption");
+        if (encryption == null) {
+            // Encryption features have been disabled on this BTP instance.
+            properties.put(CRED_STORE_PROPERTY_PREFIX + ".clientPrivateKey", "encryption-disabled");
+            properties.put(CRED_STORE_PROPERTY_PREFIX + ".serverPublicKey", "encryption-disabled");
+            return;
+        }
+
+        String clientPrivateKey = encryption.get("client_private_key").toString();
+        String serverPublicKey = encryption.get("server_public_key").toString();
+
+        properties.put(CRED_STORE_PROPERTY_PREFIX + ".clientPrivateKey", clientPrivateKey);
+        properties.put(CRED_STORE_PROPERTY_PREFIX + ".serverPublicKey", serverPublicKey);
+    }
+
+    @Override
+    public CfEnvProcessorProperties getProperties() {
+        return CfEnvProcessorProperties.builder()
+                .propertyPrefixes(CRED_STORE_PROPERTY_PREFIX)
+                .serviceName("CredentialStore")
+                .build();
+    }
+
+}