atomic update

Author: kahing

etleap/src/main/java/us/hxbc/etleap/Main.java

@@ -11,6 +11,6 @@ public static void main(String[] args) throws MalformedURLException {
         }
 
         URL url = new URL(args[0]);
-        new UpdateService(url).start();
+        new UpdateService(url).start(5 * 60 * 1024);
     }
 }

etleap/src/main/java/us/hxbc/etleap/UpdateService.java

@@ -42,7 +42,7 @@ void update() {
         }
     }
 
-    public void start() {
+    public void start(int sleep) {
         runner = new Thread(() -> {
             logger.info("started, polling {} every 5 minutes", url);
 
@@ -55,7 +55,7 @@ public void start() {
                     }
 
                     try {
-                        cv.wait(5 * 60 * 1000); // 5 minutes
+                        cv.wait(sleep);
                     } catch (InterruptedException e) {
                         continue;
                     }

etleap/src/main/java/us/hxbc/etleap/config/FileConfig.java

@@ -14,6 +14,7 @@
 import java.nio.file.OpenOption;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
 import java.nio.file.StandardOpenOption;
 
 import static com.google.common.base.Throwables.propagate;
@@ -36,21 +37,37 @@ public class FileConfig {
         tokens.pushBack(); // give the closing brace to parent
     }
 
+    InputStream openStream() throws IOException {
+        return getUpdatePath().openStream();
+    }
+
+    void update(InputStream is) throws IOException {
+        Path t = Files.createTempFile(getPath().getParent(), getPath().getFileName().toString(), ".tmp");
+
+        try (OutputStream os = Files.newOutputStream(t,
+                StandardOpenOption.CREATE, StandardOpenOption.WRITE)) {
+            ByteStreams.copy(is, os);
+        } catch (IOException e) {
+            logger.error("unable to write file", e);
+        }
+
+        try {
+            Files.move(t, getPath(), StandardCopyOption.ATOMIC_MOVE, StandardCopyOption.REPLACE_EXISTING);
+        } catch (IOException e) {
+            logger.error("unable to rename", e);
+        }
+    }
+
     void apply() {
-        logger.info("replacing {} with {}", path, updatePath);
+        logger.info("replacing {} with {}", getPath(), getUpdatePath());
         try {
-            Files.createDirectories(path.getParent());
+            Files.createDirectories(getPath().getParent());
         } catch (IOException e) {
             logger.error("unable to create path", e);
         }
 
-        try (InputStream is = updatePath.openStream()) {
-            try (OutputStream os = Files.newOutputStream(path,
-                    StandardOpenOption.CREATE, StandardOpenOption.WRITE)) {
-                ByteStreams.copy(is, os);
-            } catch (IOException e) {
-                logger.error("unable to replace file", e);
-            }
+        try (InputStream is = openStream()) {
+            update(is);
         } catch (IOException e) {
             logger.error("unable to download update", e);
             throw propagate(e);

etleap/src/test/java/us/hxbc/etleap/UpdateServiceTest.java

@@ -4,21 +4,15 @@
 import org.junit.Test;
 
 import java.io.StringReader;
-import java.net.URL;
 
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.when;
+import static org.mockito.Mockito.*;
 
 public class UpdateServiceTest {
     UpdateService service;
 
     @Before
     public void setUp() throws Exception {
         service = mock(UpdateService.class);
-    }
-
-    @Test
-    public void testUpdate() throws Exception {
         String data = "file { \"/tmp/hello\":\n" +
                 "source => \"http://host.com/path/to/hello\"\n" +
                 "}\n" +
@@ -27,6 +21,18 @@ public void testUpdate() throws Exception {
                 "}";
 
         when(service.openURL()).thenReturn(new StringReader(data));
+    }
+
+    @Test
+    public void testUpdate() throws Exception {
         service.update();
+        verify(service, atLeast(1)).update();
+    }
+
+    @Test
+    public void testStart() throws Exception {
+        service.start(1000);
+        Thread.sleep(1500);
+        service.stop();
     }
-}
+}

etleap/src/test/java/us/hxbc/etleap/config/FileConfigTest.java

@@ -2,19 +2,22 @@
 
 import org.junit.Before;
 import org.junit.Test;
+import org.mockito.verification.VerificationMode;
 
+import java.io.ByteArrayInputStream;
 import java.io.StreamTokenizer;
 import java.io.StringReader;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.*;
 
 public class FileConfigTest {
     FileConfig config;
 
     @Before
     public void setup() throws Exception {
         String data = "\"/tmp/hello\":\n" +
-                "source => \"http://host.com/path/to/hello\"\n" +
+                "source => \"http://example.com/path/to/hello\"\n" +
                 "}";
         StreamTokenizer tokens = new StreamTokenizer(new StringReader(data));
         tokens.quoteChar('"');
@@ -33,6 +36,17 @@ public void testGetPath() throws Exception {
 
     @Test
     public void testGetUpdatePath() throws Exception {
-        assertThat(config.getUpdatePath().toString()).isEqualTo("http://host.com/path/to/hello");
+        assertThat(config.getUpdatePath().toString()).isEqualTo("http://example.com/path/to/hello");
+    }
+
+    @Test
+    public void testApply() throws Exception {
+        FileConfig configMock = mock(FileConfig.class);
+        when(configMock.getPath()).thenReturn(config.getPath());
+        when(configMock.getUpdatePath()).thenReturn(config.getUpdatePath());
+        when(configMock.openStream()).thenReturn(new ByteArrayInputStream("hello world".getBytes()));
+        configMock.apply();
+        verify(configMock, atLeastOnce()).apply();
+        assertThat(configMock.getPath()).hasContent("hello world");
     }
 }