Full advisory locking (#167)

Implement full advisory locking, a side-struct which is used to coordinate, but do not lock the actual data we operate on, as some OS-es does not know to handle that.

This means that Mimir now does not lock data it operates on, to make possible combining of features like exclusive access and cache purge on certain operating systems.

Author: cstamas

core/src/main/java/eu/maveniverse/maven/mimir/shared/SessionConfig.java

@@ -83,6 +83,8 @@ public interface SessionConfig {
 
     Path basedir();
 
+    Path baseLocksDir();
+
     Path propertiesPath();
 
     Map<String, String> userProperties();
@@ -272,6 +274,7 @@ private static class Impl implements SessionConfig {
             private final boolean ignoreErrorAtSessionEnd;
             private final String mimirVersion;
             private final Path basedir;
+            private final Path baseLocksDir;
             private final Path propertiesPath;
             private final Map<String, String> userProperties;
             private final Map<String, String> systemProperties;
@@ -301,6 +304,7 @@ private Impl(
                 this.basedir = basedir == null
                         ? FileUtils.discoverBaseDirectory("mimir.basedir", ".mimir")
                         : FileUtils.canonicalPath(basedir);
+                this.baseLocksDir = this.basedir.resolve("locks");
                 this.propertiesPath = propertiesPath == null
                         ? this.basedir.resolve("session.properties")
                         : FileUtils.canonicalPath(this.basedir.resolve(propertiesPath));
@@ -382,6 +386,11 @@ public Path basedir() {
                 return basedir;
             }
 
+            @Override
+            public Path baseLocksDir() {
+                return baseLocksDir;
+            }
+
             @Override
             public Path propertiesPath() {
                 return propertiesPath;

daemon-slim/src/main/java/eu/maveniverse/maven/mimir/daemon/DaemonConfig.java

@@ -22,7 +22,7 @@ public class DaemonConfig {
     public static DaemonConfig with(SessionConfig sessionConfig) {
         requireNonNull(sessionConfig, "config");
 
-        Path daemonLockDir = sessionConfig.basedir().resolve("daemon");
+        Path daemonLockDir = sessionConfig.baseLocksDir().resolve("daemon");
         Path socketPath = sessionConfig.basedir().resolve(Handle.DEFAULT_SOCKET_PATH);
         String systemNode = "file";
         boolean preSeedItself = false;

node/daemon/src/main/java/eu/maveniverse/maven/mimir/node/daemon/DaemonNodeConfig.java

@@ -27,9 +27,10 @@ public static DaemonNodeConfig with(SessionConfig sessionConfig) {
                     .basedir()
                     .resolve(sessionConfig.effectiveProperties().get("mimir.daemon.basedir")));
         }
-
-        Path daemonLockDir = daemonBasedir.resolve("daemon");
-        Path daemonStarterLockDir = daemonBasedir.resolve("daemonStarter");
+        // here we cannot use sessionConfig.baseLocksDir() as we may moved daemon basedir above
+        Path locks = daemonBasedir.resolve("locks");
+        Path daemonLockDir = locks.resolve("daemon");
+        Path daemonStarterLockDir = locks.resolve("starter");
         Path socketPath = daemonBasedir.resolve(Handle.DEFAULT_SOCKET_PATH);
         Path daemonJavaHome = FileUtils.canonicalPath(daemonBasedir.resolve(sessionConfig
                 .effectiveProperties()

node/file/src/main/java/eu/maveniverse/maven/mimir/node/file/FileNode.java

@@ -48,6 +48,7 @@
 public final class FileNode extends NodeSupport implements SystemNode {
 
     private final Path basedir;
+    private final Path baseLockDir;
     private final boolean mayLink;
     private final boolean exclusiveAccess;
     private final FileNodeConfig.CachePurge cachePurge;
@@ -60,6 +61,7 @@ public final class FileNode extends NodeSupport implements SystemNode {
 
     public FileNode(
             Path basedir,
+            Path baseLockDir,
             boolean mayLink,
             boolean exclusiveAccess,
             FileNodeConfig.CachePurge cachePurge,
@@ -83,7 +85,9 @@ public FileNode(
         }
 
         Files.createDirectories(basedir);
-        this.directoryLocker.lockDirectory(basedir, exclusiveAccess);
+        Files.createDirectories(baseLockDir);
+        this.baseLockDir = baseLockDir;
+        this.directoryLocker.lockDirectory(baseLockDir, exclusiveAccess);
 
         // at this point, if cachePurge != OFF we have exclusiveAccess=true and we "own" exclusive lock over storage
         if (cachePurge == FileNodeConfig.CachePurge.OFF) {
@@ -253,7 +257,7 @@ protected void doClose() throws IOException {
                 FileUtils.deleteRecursively(backup);
             }
         } finally {
-            directoryLocker.unlockDirectory(basedir);
+            directoryLocker.unlockDirectory(baseLockDir);
         }
     }
 

node/file/src/main/java/eu/maveniverse/maven/mimir/node/file/FileNodeConfig.java

@@ -63,6 +63,7 @@ public static FileNodeConfig with(SessionConfig sessionConfig) {
         requireNonNull(sessionConfig, "config");
 
         Path basedir = sessionConfig.basedir().resolve("local");
+        Path baseLockDir = sessionConfig.baseLocksDir().resolve(NAME);
         boolean mayLink = true;
         List<String> checksumAlgorithms = Arrays.asList("SHA-1", "SHA-512");
         String keyResolver = SimpleKeyResolverFactory.NAME;
@@ -95,28 +96,26 @@ public static FileNodeConfig with(SessionConfig sessionConfig) {
             cachePurge = CachePurge.valueOf(sessionConfig.effectiveProperties().get("mimir.file.cachePurge"));
         }
 
-        return new FileNodeConfig(basedir, mayLink, checksumAlgorithms, keyResolver, exclusiveAccess, cachePurge);
+        return new FileNodeConfig(
+                basedir, baseLockDir, mayLink, checksumAlgorithms, keyResolver, exclusiveAccess, cachePurge);
     }
 
     public static FileNodeConfig of(
             Path basedir,
+            Path baseLockDir,
             boolean mayLink,
             List<String> checksumAlgorithms,
             String keyResolver,
             boolean exclusiveAccess,
             CachePurge cachePurge) {
         return new FileNodeConfig(
-                FileUtils.canonicalPath(basedir),
-                mayLink,
-                checksumAlgorithms,
-                keyResolver,
-                exclusiveAccess,
-                cachePurge);
+                basedir, baseLockDir, mayLink, checksumAlgorithms, keyResolver, exclusiveAccess, cachePurge);
     }
 
     public static final String NAME = "file";
 
     private final Path basedir;
+    private final Path baseLockDir;
     private final boolean mayLink;
     private final List<String> checksumAlgorithms;
     private final String keyResolver;
@@ -125,12 +124,14 @@ public static FileNodeConfig of(
 
     private FileNodeConfig(
             Path basedir,
+            Path baseLockDir,
             boolean mayLink,
             List<String> checksumAlgorithms,
             String keyResolver,
             boolean exclusiveAccess,
             CachePurge cachePurge) {
         this.basedir = basedir;
+        this.baseLockDir = baseLockDir;
         this.mayLink = mayLink;
         this.checksumAlgorithms = List.copyOf(checksumAlgorithms);
         this.keyResolver = keyResolver;
@@ -146,6 +147,10 @@ public Path basedir() {
         return basedir;
     }
 
+    public Path baseLockDir() {
+        return baseLockDir;
+    }
+
     public boolean mayLink() {
         return mayLink;
     }

node/file/src/main/java/eu/maveniverse/maven/mimir/node/file/FileNodeFactory.java

@@ -62,6 +62,7 @@ public FileNode createSystemNode(SessionConfig sessionConfig) throws IOException
 
         return new FileNode(
                 fileNodeConfig.basedir(),
+                fileNodeConfig.baseLockDir(),
                 fileNodeConfig.mayLink(),
                 fileNodeConfig.exclusiveAccess(),
                 fileNodeConfig.cachePurge(),

node/jgroups/src/test/java/eu/maveniverse/maven/mimir/jgroups/JGroupsNodeTest.java

@@ -43,6 +43,7 @@ void smoke() throws Exception {
         Files.writeString(contentPath, content);
 
         FileNodeConfig configOne = FileNodeConfig.of(
+                one,
                 one,
                 true,
                 Collections.singletonList("SHA-1"),
@@ -51,6 +52,7 @@ void smoke() throws Exception {
                 FileNodeConfig.CachePurge.OFF);
         FileNode nodeOne = new FileNode(
                 configOne.basedir(),
+                configOne.baseLockDir(),
                 configOne.mayLink(),
                 configOne.exclusiveAccess(),
                 configOne.cachePurge(),
@@ -59,6 +61,7 @@ void smoke() throws Exception {
                 Map.of(Sha1ChecksumAlgorithmFactory.NAME, new Sha1ChecksumAlgorithmFactory()),
                 DirectoryLocker.INSTANCE);
         FileNodeConfig configTwo = FileNodeConfig.of(
+                two,
                 two,
                 true,
                 Collections.singletonList("SHA-1"),
@@ -67,6 +70,7 @@ void smoke() throws Exception {
                 FileNodeConfig.CachePurge.OFF);
         FileNode nodeTwo = new FileNode(
                 configTwo.basedir(),
+                configTwo.baseLockDir(),
                 configTwo.mayLink(),
                 configTwo.exclusiveAccess(),
                 configTwo.cachePurge(),