UnixPath support for atomicWrite, getFilename, getParent, setLastModifiedTime

2 files changed, 80 insertions, 10 deletions

diff --git a/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/task/util/file/UnixPath.java b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/task/util/file/UnixPath.java
index 268e0a5ccfd..f6eb7190db3 100644
--- a/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/task/util/file/UnixPath.java
+++ b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/task/util/file/UnixPath.java
@@ -11,6 +11,7 @@ import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.nio.file.StandardCopyOption;
 import java.nio.file.attribute.FileAttribute;
+import java.nio.file.attribute.FileTime;
 import java.nio.file.attribute.GroupPrincipal;
 import java.nio.file.attribute.PosixFileAttributeView;
 import java.nio.file.attribute.PosixFileAttributes;
@@ -37,22 +38,33 @@ import static com.yahoo.yolean.Exceptions.uncheck;
 public class UnixPath {
     private final Path path;
 
-    public UnixPath(Path path) {
-        this.path = path;
-    }
+    public UnixPath(Path path) { this.path = path; }
+    public UnixPath(String path) { this(Paths.get(path)); }
 
-    public UnixPath(String path) {
-        this(Paths.get(path));
-    }
+    public Path toPath() { return path; }
+    public UnixPath resolve(String relativeOrAbsolutePath) { return new UnixPath(path.resolve(relativeOrAbsolutePath)); }
+
+    public UnixPath getParent() {
+        Path parentPath = path.getParent();
+        if (parentPath == null) {
+            throw new IllegalStateException("Path has no parent directory: '" + path + "'");
+        }
 
-    public Path toPath() {
-        return path;
+        return new UnixPath(parentPath);
     }
 
-    public boolean exists() {
-        return Files.exists(path);
+    public String getFilename() {
+        Path filename = path.getFileName();
+        if (filename == null) {
+            // E.g. "/".
+            throw new IllegalStateException("Path has no filename: '" + path.toString() + "'");
+        }
+
+        return filename.toString();
     }
 
+    public boolean exists() { return Files.exists(path); }
+
     public String readUtf8File() {
         return new String(readBytes(), StandardCharsets.UTF_8);
     }
@@ -91,6 +103,18 @@ public class UnixPath {
         return this;
     }
 
+    public void atomicWriteUt8(String content) {
+        atomicWriteBytes(content.getBytes(StandardCharsets.UTF_8));
+    }
+
+    /** Write a file to the same dir as this, and then atomically move it to this' path. */
+    public void atomicWriteBytes(byte[] content) {
+        Path tempPath = path.getParent().resolve(path.getFileName() + ".10Ia2f4N5");
+        UnixPath temporaryPath = getParent().resolve(getFilename() + ".10Ia2f4N5");
+        temporaryPath.writeBytes(content);
+        temporaryPath.atomicMove(path);
+    }
+
     public String getPermissions() {
         return getAttributes().permissions();
     }
@@ -135,6 +159,10 @@ public class UnixPath {
         return getAttributes().lastModifiedTime();
     }
 
+    public void setLastModifiedTime(Instant instant) {
+        uncheck(() -> Files.setLastModifiedTime(path, FileTime.from(Instant.now())));
+    }
+
     public FileAttributes getAttributes() {
         PosixFileAttributes attributes = uncheck(() ->
                 Files.getFileAttributeView(path, PosixFileAttributeView.class).readAttributes());
diff --git a/node-admin/src/test/java/com/yahoo/vespa/hosted/node/admin/task/util/file/UnixPathTest.java b/node-admin/src/test/java/com/yahoo/vespa/hosted/node/admin/task/util/file/UnixPathTest.java
index 3b839f7f446..3159689c22e 100644
--- a/node-admin/src/test/java/com/yahoo/vespa/hosted/node/admin/task/util/file/UnixPathTest.java
+++ b/node-admin/src/test/java/com/yahoo/vespa/hosted/node/admin/task/util/file/UnixPathTest.java
@@ -3,6 +3,7 @@
 package com.yahoo.vespa.hosted.node.admin.task.util.file;
 
 import com.yahoo.vespa.test.file.TestFileSystem;
+import org.junit.ComparisonFailure;
 import org.junit.Test;
 
 import java.nio.file.FileSystem;
@@ -13,6 +14,7 @@ import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 /**
  * @author hakonhall
@@ -124,4 +126,44 @@ public class UnixPathTest {
         assertFalse(dir1 + " deleted recursively", Files.exists(dir1));
     }
 
+    @Test
+    public void atomicWrite() {
+        var path = new UnixPath(fs.getPath("/dir/foo"));
+        path.createParents();
+        path.writeUtf8File("bar");
+        path.atomicWriteUt8("bar v2");
+        assertEquals("bar v2", path.readUtf8File());
+    }
+
+    @Test
+    public void testParentAndFilename() {
+        var absolutePath = new UnixPath("/foo/bar");
+        assertEquals("/foo", absolutePath.getParent().toString());
+        assertEquals("bar", absolutePath.getFilename());
+
+        var pathWithoutSlash = new UnixPath("foo");
+        assertRuntimeException(IllegalStateException.class, "Path has no parent directory: 'foo'", () -> pathWithoutSlash.getParent());
+        assertEquals("foo", pathWithoutSlash.getFilename());
+
+        var pathWithSlash = new UnixPath("/foo");
+        assertEquals("/", pathWithSlash.getParent().toString());
+        assertEquals("foo", pathWithSlash.getFilename());
+
+        assertRuntimeException(IllegalStateException.class, "Path has no parent directory: '/'", () -> new UnixPath("/").getParent());
+        assertRuntimeException(IllegalStateException.class, "Path has no filename: '/'", () -> new UnixPath("/").getFilename());
+    }
+
+    private <T extends RuntimeException> void assertRuntimeException(Class<T> baseClass, String message, Runnable runnable) {
+        try {
+            runnable.run();
+            fail("No exception was thrown");
+        } catch (RuntimeException e) {
+            if (!baseClass.isInstance(e)) {
+                throw new ComparisonFailure("Exception class mismatch", baseClass.getName(), e.getClass().getName());
+            }
+
+            assertEquals(message, e.getMessage());
+        }
+    }
+
 }