feat(storage): add FilesystemArtifactStore (one impl of ArtifactStore)

cameleer-server-app/src/main/java/com/cameleer/server/app/storage/FilesystemArtifactStore.java

@@ -0,0 +1,68 @@
+package com.cameleer.server.app.storage;
+
+import com.cameleer.server.core.storage.ArtifactCoordinates;
+import com.cameleer.server.core.storage.ArtifactStore;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+public class FilesystemArtifactStore implements ArtifactStore {
+
+    private final Path root;
+
+    public FilesystemArtifactStore(String root) {
+        this.root = Path.of(root);
+    }
+
+    private Path pathOf(ArtifactCoordinates coords) {
+        return root.resolve(coords.filesystemKey());
+    }
+
+    @Override
+    public String put(ArtifactCoordinates coords, InputStream bytes, long size) throws IOException {
+        Path target = pathOf(coords);
+        Files.createDirectories(target.getParent());
+        try (InputStream in = bytes) {
+            Files.copy(in, target, java.nio.file.StandardCopyOption.REPLACE_EXISTING);
+        }
+        return target.toString();
+    }
+
+    @Override
+    public InputStream get(ArtifactCoordinates coords) throws IOException {
+        return Files.newInputStream(pathOf(coords));
+    }
+
+    @Override
+    public boolean exists(ArtifactCoordinates coords) {
+        return Files.exists(pathOf(coords));
+    }
+
+    @Override
+    public void delete(ArtifactCoordinates coords) throws IOException {
+        Path target = pathOf(coords);
+        Files.deleteIfExists(target);
+        // Sweep empty {appId}/v{n}/ then {appId}/ if now empty.
+        Path versionDir = target.getParent();
+        if (versionDir != null && Files.isDirectory(versionDir) && isEmpty(versionDir)) {
+            Files.delete(versionDir);
+            Path appDir = versionDir.getParent();
+            if (appDir != null && Files.isDirectory(appDir) && isEmpty(appDir)) {
+                Files.delete(appDir);
+            }
+        }
+    }
+
+    @Override
+    public String locator(ArtifactCoordinates coords) {
+        return pathOf(coords).toString();
+    }
+
+    private static boolean isEmpty(Path dir) throws IOException {
+        try (var entries = Files.list(dir)) {
+            return entries.findFirst().isEmpty();
+        }
+    }
+}

cameleer-server-app/src/test/java/com/cameleer/server/app/storage/FilesystemArtifactStoreTest.java

@@ -0,0 +1,61 @@
+package com.cameleer.server.app.storage;
+
+import com.cameleer.server.core.storage.ArtifactCoordinates;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.UUID;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class FilesystemArtifactStoreTest {
+
+    @Test
+    void roundTripsBytes(@TempDir Path tmp) throws Exception {
+        FilesystemArtifactStore store = new FilesystemArtifactStore(tmp.toString());
+        ArtifactCoordinates c = new ArtifactCoordinates("default", UUID.randomUUID(), 1);
+
+        byte[] payload = "hello-jar".getBytes();
+        store.put(c, new ByteArrayInputStream(payload), payload.length);
+
+        assertThat(store.exists(c)).isTrue();
+        try (InputStream in = store.get(c)) {
+            assertThat(in.readAllBytes()).isEqualTo(payload);
+        }
+    }
+
+    @Test
+    void deleteRemovesFileAndEmptyParents(@TempDir Path tmp) throws Exception {
+        FilesystemArtifactStore store = new FilesystemArtifactStore(tmp.toString());
+        UUID appId = UUID.randomUUID();
+        ArtifactCoordinates c = new ArtifactCoordinates("default", appId, 1);
+        store.put(c, new ByteArrayInputStream("x".getBytes()), 1);
+
+        store.delete(c);
+
+        assertThat(store.exists(c)).isFalse();
+        // {tmp}/{appId}/v1/ should be gone too
+        assertThat(Files.exists(tmp.resolve(appId.toString()).resolve("v1"))).isFalse();
+    }
+
+    @Test
+    void deleteIsIdempotent(@TempDir Path tmp) throws Exception {
+        FilesystemArtifactStore store = new FilesystemArtifactStore(tmp.toString());
+        ArtifactCoordinates c = new ArtifactCoordinates("default", UUID.randomUUID(), 1);
+        store.delete(c); // no exception
+        assertThat(store.exists(c)).isFalse();
+    }
+
+    @Test
+    void locatorMatchesLegacyAbsolutePath(@TempDir Path tmp) {
+        FilesystemArtifactStore store = new FilesystemArtifactStore(tmp.toString());
+        UUID appId = UUID.fromString("11111111-1111-1111-1111-111111111111");
+        ArtifactCoordinates c = new ArtifactCoordinates("default", appId, 7);
+        assertThat(store.locator(c))
+                .isEqualTo(tmp.resolve("11111111-1111-1111-1111-111111111111/v7/app.jar").toString());
+    }
+}