use @Slf4j (+logback) for logging instead of System.out/err.println (#165)

Co-authored-by: Michael Hoennig <michael@hoennig.de>
Reviewed-on: https://dev.hostsharing.net/hostsharing/hs.hsadmin.ng/pulls/165
Reviewed-by: Marc Sandlus <marc.sandlus@hostsharing.net>

src/main/java/net/hostsharing/hsadminng/config/RealCasAuthenticator.java

@@ -2,6 +2,7 @@ package net.hostsharing.hsadminng.config;
 
 import io.micrometer.core.annotation.Timed;
 import lombok.SneakyThrows;
+import lombok.extern.slf4j.Slf4j;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.security.authentication.BadCredentialsException;
 import org.springframework.util.LinkedMultiValueMap;
@@ -14,6 +15,8 @@ import javax.xml.parsers.DocumentBuilderFactory;
 import javax.xml.parsers.ParserConfigurationException;
 import java.io.IOException;
 
+// HOWTO add logger
+@Slf4j
 public class RealCasAuthenticator implements CasAuthenticator {
 
     @Value("${hsadminng.cas.server}")
@@ -32,7 +35,8 @@ public class RealCasAuthenticator implements CasAuthenticator {
                 ? fetchServiceTicket(ticket)
                 : ticket;
         final var userName = extractUserName(verifyServiceTicket(serviceTicket));
-        System.err.println("CAS-user: " + userName);
+        // HOWTO log some message for a certain log level (trace, debug, info, warn, error)
+        log.debug("CAS-user: {}", userName);
         return userName;
     }
 
@@ -65,9 +69,7 @@ public class RealCasAuthenticator implements CasAuthenticator {
     private String extractUserName(final Document verification) {
 
         if (verification.getElementsByTagName("cas:authenticationSuccess").getLength() == 0) {
-            System.err.println("CAS service ticket could not be validated");
-            System.err.println(verification);
-            throwBadCredentialsException("CAS service ticket could not be validated");
+            throwBadCredentialsException("CAS service ticket could not be verified");
         }
         return verification.getElementsByTagName("cas:user").item(0).getTextContent();
     }

src/main/java/net/hostsharing/hsadminng/errors/RestResponseEntityExceptionHandler.java

@@ -28,6 +28,7 @@ import java.util.regex.Pattern;
 import static net.hostsharing.hsadminng.errors.CustomErrorResponse.*;
 
 @ControllerAdvice
+// HOWTO handle exceptions to produce specific http error codes and sensible error messages
 public class RestResponseEntityExceptionHandler
         extends ResponseEntityExceptionHandler {
 

src/main/java/net/hostsharing/hsadminng/hash/HashGenerator.java

@@ -121,10 +121,4 @@ public final class HashGenerator {
         }
         return withSalt(stringBuilder.toString());
     }
-
-    public static void main(String[] args) {
-        System.out.println(
-            HashGenerator.using(Algorithm.LINUX_YESCRYPT).withRandomSalt().hash("my plaintext domain transfer passphrase")
-        );
-    }
 }

src/main/java/net/hostsharing/hsadminng/hs/hosting/asset/validators/Dns.java

@@ -125,10 +125,4 @@ public class Dns {
             return Result.fromException(exception);
         }
     }
-
-    public static void main(String[] args) {
-        final var result = new Dns("example.org").fetchRecordsOfType("TXT");
-        System.out.println(result);
-    }
-
 }

src/main/java/net/hostsharing/hsadminng/rbac/generator/RbacSpec.java

@@ -1261,15 +1261,11 @@ public class RbacSpec {
                         m -> isStatic(m.getModifiers()) && m.getName().equals("main")
                 )
                 .findFirst()
-                .orElse(null);
-        if (mainMethod != null) {
-            try {
-                mainMethod.invoke(null, new Object[] { null });
-            } catch (IllegalAccessException | InvocationTargetException e) {
-                throw new RuntimeException(e);
-            }
-        } else {
-            System.err.println("WARNING: no main method in: " + c.getName() + " => no RBAC rules generated");
+                .orElseThrow(() -> new RuntimeException("no main method in: " + c.getName() + " => cannot generate RBAC rules"));
+        try {
+            mainMethod.invoke(null, new Object[] { null });
+        } catch (IllegalAccessException | InvocationTargetException e) {
+            throw new RuntimeException(e);
         }
     }
 

src/main/java/net/hostsharing/hsadminng/rbac/generator/RbacViewMermaidFlowchartGenerator.java

@@ -202,6 +202,5 @@ public class RbacViewMermaidFlowchartGenerator {
                     .replace("%{flowchart}", flowchart.toString())
                     .replace("%{case}", forCase == null ? "" : " " + forCase),
                 StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING);
-        System.out.println("Markdown-File: " + path.toAbsolutePath());
     }
 }

src/main/java/net/hostsharing/hsadminng/rbac/generator/RbacViewPostgresGenerator.java

@@ -49,6 +49,5 @@ public class RbacViewPostgresGenerator {
                 toString(),
                 StandardOpenOption.CREATE,
                 StandardOpenOption.TRUNCATE_EXISTING);
-        System.out.println(outputPath.toAbsolutePath());
     }
 }

src/main/java/net/hostsharing/hsadminng/rbac/generator/RolesGrantsAndPermissionsGenerator.java

@@ -358,9 +358,6 @@ class RolesGrantsAndPermissionsGenerator {
     }
 
     private String roleRef(final PostgresTriggerReference rootRefVar, final RbacSpec.RbacRoleDefinition roleDef) {
-        if (roleDef == null) {
-            System.out.println("null");
-        }
         if (roleDef.getEntityAlias().isGlobal()) {
             return "rbac.global_ADMIN()";
         }

src/main/resources/application.yml

@@ -68,8 +68,10 @@ metrics:
                 server:
                     requests: true
 
+# HOWTO set logging-levels for certain Java packages (trace, debug, info, warn, error)
 logging:
     level:
-        org:
-            springframework:
-                security: TRACE
+        org.springframework.security: info
+# HOWTO configure logging, e.g. logging to a separate file, see:
+#   https://docs.spring.io/spring-boot/reference/features/logging.html
+