Detect which condition didn't match and log the cause when configuring DPS as default DNS (mageddo#585)

* adjusting dev

* refactoring file edition conditions to rule pattern this way I can detect which condition didn't match and log the cause

* [Gradle Release Plugin] - new version commit:  '3.30.2-snapshot'.

* release notes

Author: mageddo

RELEASE-NOTES.md

@@ -1,3 +1,7 @@
+## 3.30.2
+* Detect which condition didn't match and log the cause when configuring DPS as default DNS #580
+* Fixed backend develop docker-compose.yml
+
 ## 3.30.1
 * Implemented but not exposed Canary Rate Threshold Circuit Breaker Strategy. #533
 

docker-compose-dev.yml

@@ -1,11 +1,12 @@
 version: '3'
 services:
   backend:
-    image: openjdk:19-jdk
+    image: openjdk:21-jdk
     environment:
+      MG_RESOLVCONF: /host/run/stub-resolv.conf
       MG_DPS_NETWORK: true
       MG_DPS_NETWORK_AUTO_CONNECT: true
-      MG_NO_REMOTE_SERVERS: true
+      MG_NO_REMOTE_SERVERS: false
       MG_LOG_LEVEL: DEBUG
 #      MG_LOG_LEVEL: DEBUG
 #      MG_DPS_NETWORK: true
@@ -18,7 +19,7 @@ services:
     volumes:
       - ./build/libs:/app
       - /var/run/docker.sock:/var/run/docker.sock
-#      - /etc/resolv.conf:/etc/resolv.conf
+#      - /run/systemd/resolve/:/host/run/
     #      - /etc/systemd/:/host/etc/systemd/
     working_dir: /app
     command: java -jar dns-proxy-server-3.16.1-snapshot-all.jar

gradle.properties

@@ -1 +1 @@
-version=3.30.1-snapshot
+version=3.30.2-snapshot

src/main/java/com/mageddo/dnsproxyserver/dnsconfigurator/linux/DnsConfiguratorLinux.java

@@ -5,20 +5,25 @@
 import com.mageddo.dnsproxyserver.dnsconfigurator.DnsConfigurator;
 import com.mageddo.dnsproxyserver.dnsconfigurator.linux.ResolvFile.Type;
 import com.mageddo.dnsproxyserver.systemd.ResolvedService;
+import com.mageddo.io.path.predicate.PathExistsPredicate;
+import com.mageddo.io.path.predicate.PathIsFilePredicate;
+import com.mageddo.io.path.predicate.PathIsWritablePredicate;
 import com.mageddo.net.IpAddr;
 import com.mageddo.utils.Tests;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
+import org.apache.commons.lang3.ClassUtils;
 
 import javax.enterprise.inject.Default;
 import javax.inject.Inject;
 import javax.inject.Singleton;
-import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Collections;
 import java.util.List;
+import java.util.Optional;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.Predicate;
 
 import static com.mageddo.dnsproxyserver.utils.Splits.splitToPaths;
 import static org.apache.commons.lang3.ObjectUtils.firstNonNull;
@@ -32,6 +37,11 @@ public class DnsConfiguratorLinux implements DnsConfigurator {
   private final AtomicBoolean resolvedConfigured = new AtomicBoolean();
 
   private volatile AtomicReference<ResolvFile> confFile;
+  private final List<Predicate<Path>> pathPredicates = List.of(
+    new PathExistsPredicate(),
+    new PathIsFilePredicate(),
+    new PathIsWritablePredicate()
+  );
 
   @Override
   public void configure(IpAddr addr) {
@@ -46,8 +56,7 @@ public void configure(IpAddr addr) {
     if (confFile.isResolvconf()) {
       final var overrideNameServers = Configs
         .getInstance()
-        .getResolvConfOverrideNameServers()
-        ;
+        .getResolvConfOverrideNameServers();
       ResolvconfConfigurator.process(confFile.getPath(), addr, overrideNameServers);
     } else if (confFile.isResolved()) {
       this.configureResolved(addr, confFile);
@@ -81,16 +90,14 @@ ResolvFile getConfFile() {
   }
 
   ResolvFile findBestConfFile() {
-    return buildConfPaths()
+    return this.buildConfPaths()
       .stream()
       .filter(it -> {
-          final var valid = Files.exists(it)
-            && !Files.isDirectory(it)
-            && Files.isWritable(it);
-          if (!valid) {
-            log.info("status=noValidConfFile, file={}", it);
-          }
-          return valid;
+          final var unmetPredicate = this.findUnmetPredicate(it);
+          unmetPredicate.ifPresent(pathPredicate -> {
+            log.info("status=noValidConfFile, file={}, condition={}", it, ClassUtils.getSimpleName(pathPredicate));
+          });
+          return unmetPredicate.isEmpty();
         }
       )
       .map(this::toResolvFile)
@@ -99,6 +106,13 @@ ResolvFile findBestConfFile() {
       ;
   }
 
+  private Optional<Predicate<Path>> findUnmetPredicate(Path it) {
+    return this.pathPredicates
+      .stream()
+      .filter(p -> !p.test(it))
+      .findFirst();
+  }
+
   List<Path> buildConfPaths() {
     return Objects.firstNonNull(
       splitToPaths(getConfigResolvPaths()),
@@ -144,7 +158,7 @@ static void tryRestartResolved() {
     } catch (Throwable e) {
       log.warn(
         "status=can't restart resolved service, please run: "
-          + "'service systemd-resolved restart' to apply DPS as default DNS.\n{}",
+        + "'service systemd-resolved restart' to apply DPS as default DNS.\n{}",
         e.getMessage()
       );
     }

src/main/java/com/mageddo/io/path/predicate/PathExistsPredicate.java

@@ -0,0 +1,12 @@
+package com.mageddo.io.path.predicate;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.function.Predicate;
+
+public class PathExistsPredicate implements Predicate<Path> {
+  @Override
+  public boolean test(Path p) {
+    return Files.exists(p);
+  }
+}

src/main/java/com/mageddo/io/path/predicate/PathIsFilePredicate.java

@@ -0,0 +1,12 @@
+package com.mageddo.io.path.predicate;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.function.Predicate;
+
+public class PathIsFilePredicate implements Predicate<Path> {
+  @Override
+  public boolean test(Path path) {
+    return !Files.isDirectory(path);
+  }
+}

src/main/java/com/mageddo/io/path/predicate/PathIsWritablePredicate.java

@@ -0,0 +1,13 @@
+package com.mageddo.io.path.predicate;
+
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.function.Predicate;
+
+public class PathIsWritablePredicate implements Predicate<Path> {
+  @Override
+  public boolean test(Path path) {
+    return Files.isWritable(path);
+  }
+}