Added switcher.snapshot.watcher configuration

README.md

@@ -74,6 +74,7 @@ switcher.check -> true/false When true, it will check Switcher Keys
 switcher.relay.restrict -> true/false When true, it will check snapshot relay status
 switcher.snapshot.location -> Folder from where snapshots will be saved/read
 switcher.snapshot.auto -> true/false Automated lookup for snapshot when initializing the client
+switcher.snapshot.watcher -> true/false Enable the watcher to monitor the snapshot file for changes during runtime
 switcher.snapshot.skipvalidation -> true/false Skip snapshotValidation() that can be used for UT executions
 switcher.snapshot.updateinterval -> Enable the Snapshot Auto Update given an interval of time - e.g. 1s (s: seconds, m: minutes)
 switcher.silent -> Enable contigency given the time for the client to retry - e.g. 5s (s: seconds - m: minutes - h: hours)
@@ -252,9 +253,9 @@ MyAppFeatures.scheduleSnapshotAutoUpdate("5s", new SnapshotCallback() {
 });
 ```
 
-## Real-time snapshot reload
+## Real-time snapshot reload (Hot-swapping)
 Let the Switcher Client manage your application local snapshot.<br>
-These features allow you to configure the SDK to automatically update the snapshot in the background.
+These features allow you to configure the SDK to automatically update the snapshot during runtime.
 
 1. This feature will update the in-memory Snapshot every time the file is modified.
 
@@ -263,6 +264,15 @@ MyAppFeatures.watchSnapshot();
 MyAppFeatures.stopWatchingSnapshot();
 ```
 
+Alternatively, you can also set the Switcher Context configuration to start watching the snapshot file during the client initialization.
+
+```java
+MyAppFeatures.configure(ContextBuilder.builder()
+    .snapshotWatcher(true));
+
+MyAppFeatures.initializeClient();
+```
+
 2. You can also perform snapshot update validation to verify if there are changes to be pulled.
 
 ```java
@@ -319,7 +329,6 @@ Alternatively, you can also set the Switcher Context configuration to check duri
 
 ```java
 MyAppFeatures.configure(ContextBuilder.builder()
-    ...
     .checkSwitchers(true));
 
 MyAppFeatures.initializeClient();

pom.xml

@@ -59,9 +59,9 @@
 
 		<!-- test -->
 		<okhttp.version>5.0.0-alpha.16</okhttp.version>
-		<junit-jupiter.version>5.13.0</junit-jupiter.version>
+		<junit-jupiter.version>5.13.1</junit-jupiter.version>
 		<junit-pioneer.version>2.3.0</junit-pioneer.version>
-		<junit-platform-launcher.version>1.13.0</junit-platform-launcher.version>
+		<junit-platform-launcher.version>1.13.1</junit-platform-launcher.version>
 
 		<!-- Plugins -->
 		<maven-compiler-plugin.version>3.14.0</maven-compiler-plugin.version>

src/main/java/com/github/switcherapi/client/ContextBuilder.java

@@ -147,6 +147,15 @@ public ContextBuilder snapshotSkipValidation(boolean snapshotSkipValidation) {
 		return this;
 	}
 
+	/**
+	 * @param snapshotWatcher true/false When true, it will watch the snapshot file for changes and update the switchers accordingly
+	 * @return ContextBuilder
+	 */
+	public ContextBuilder snapshotWatcher(boolean snapshotWatcher) {
+		switcherProperties.setValue(ContextKey.SNAPSHOT_WATCHER, snapshotWatcher);
+		return this;
+	}
+
 	/**
 	 * @param retryAfter Enable contingency given the time for the client to retry - e.g. 5s (s: seconds - m: minutes - h: hours)
 	 * @return ContextBuilder

src/main/java/com/github/switcherapi/client/SwitcherConfig.java

@@ -50,6 +50,7 @@ protected void updateSwitcherConfig(SwitcherProperties properties) {
 		snapshotConfig.setLocation(properties.getValue(ContextKey.SNAPSHOT_LOCATION));
 		snapshotConfig.setAuto(properties.getBoolean(ContextKey.SNAPSHOT_AUTO_LOAD));
 		snapshotConfig.setSkipValidation(properties.getBoolean(ContextKey.SNAPSHOT_SKIP_VALIDATION));
+		snapshotConfig.setWatcher(properties.getBoolean(ContextKey.SNAPSHOT_WATCHER));
 		snapshotConfig.setUpdateInterval(properties.getValue(ContextKey.SNAPSHOT_AUTO_UPDATE_INTERVAL));
 		setSnapshot(snapshotConfig);
 
@@ -143,6 +144,7 @@ public static class SnapshotConfig {
 		private String location;
 		private boolean auto;
 		private boolean skipValidation;
+		private boolean watcher;
 		private String updateInterval;
 
 		public String getLocation() {
@@ -169,6 +171,14 @@ public void setSkipValidation(boolean skipValidation) {
 			this.skipValidation = skipValidation;
 		}
 
+		public boolean isWatcher() {
+			return watcher;
+		}
+
+		public void setWatcher(boolean watcher) {
+			this.watcher = watcher;
+		}
+
 		public String getUpdateInterval() {
 			return updateInterval;
 		}

src/main/java/com/github/switcherapi/client/SwitcherContextBase.java

@@ -114,6 +114,7 @@ protected void configureClient() {
 				.poolConnectionSize(poolSize)
 				.snapshotLocation(snapshot.getLocation())
 				.snapshotAutoLoad(snapshot.isAuto())
+				.snapshotWatcher(snapshot.isWatcher())
 				.snapshotSkipValidation(snapshot.isSkipValidation())
 				.snapshotAutoUpdateInterval(snapshot.getUpdateInterval())
 				.truststorePath(truststore.getPath())
@@ -184,6 +185,7 @@ public static void initializeClient() {
 		switcherExecutor = buildInstance();
 
 		loadSwitchers();
+		scheduleSnapshotWatcher();
 		scheduleSnapshotAutoUpdate(contextStr(ContextKey.SNAPSHOT_AUTO_UPDATE_INTERVAL));
 		ContextBuilder.preConfigure(switcherProperties);
 		SwitcherUtils.debug(logger, "Switcher Client initialized");
@@ -269,6 +271,18 @@ private static void loadSwitchers() throws SwitchersValidationException {
 		}
 	}
 
+	/**
+	 * Schedule a task to watch the snapshot file for modifications.<br>
+	 * The task will be executed in a single thread executor service.
+	 * <p>
+	 * (*) Requires client to use local settings
+	 */
+	private static void scheduleSnapshotWatcher() {
+		if (contextBol(ContextKey.SNAPSHOT_WATCHER)) {
+			watchSnapshot();
+		}
+	}
+
 	/**
 	 * Schedule a task to update the snapshot automatically.<br>
 	 * The task will be executed in a single thread executor service.
@@ -387,8 +401,8 @@ public static SwitcherRequest getSwitcher(String key) {
 	}
 
 	/**
-	 * Validate if the snapshot version is the same as the one in the API.<br>
-	 * If the version is different, it will update the snapshot in memory.
+	 * Validate if the local snapshot version is the same as remote.<br>
+	 * If the version is different, it will update the local snapshot.
 	 * 
 	 * @return true if snapshot was updated
 	 */
@@ -403,7 +417,7 @@ public static boolean validateSnapshot() {
 
 	/**
 	 * Start watching snapshot files for modifications.<br>
-	 * When the file is modified the in-memory snapshot will reload
+	 * When the file is modified the local snapshot will reload
 	 *
 	 * <p>
 	 *     (*) Requires client to use local settings
@@ -414,7 +428,7 @@ public static void watchSnapshot() {
 
 	/**
 	 * Start watching snapshot files for modifications.<br>
-	 * When the file is modified the in-memory snapshot will reload
+	 * When the file is modified the local snapshot will reload
 	 *
 	 * <p>
 	 *     (*) Requires client to use local settings

src/main/java/com/github/switcherapi/client/SwitcherPropertiesImpl.java

@@ -2,52 +2,58 @@
 
 import com.github.switcherapi.client.exception.SwitcherContextException;
 import com.github.switcherapi.client.model.ContextKey;
-import com.github.switcherapi.client.utils.SwitcherUtils;
 import org.apache.commons.lang3.StringUtils;
 
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Properties;
 
 import static com.github.switcherapi.client.remote.Constants.*;
+import static com.github.switcherapi.client.utils.SwitcherUtils.*;
 
 public class SwitcherPropertiesImpl implements SwitcherProperties {
 
 	private final Map<String, Object> properties = new HashMap<>();
 
 	public SwitcherPropertiesImpl() {
+		initDefaults();
+	}
+
+	private void initDefaults() {
 		setValue(ContextKey.ENVIRONMENT, DEFAULT_ENV);
 		setValue(ContextKey.REGEX_TIMEOUT, DEFAULT_REGEX_TIMEOUT);
 		setValue(ContextKey.TIMEOUT_MS, DEFAULT_TIMEOUT);
 		setValue(ContextKey.POOL_CONNECTION_SIZE, DEFAULT_POOL_SIZE);
 		setValue(ContextKey.SNAPSHOT_AUTO_LOAD, false);
 		setValue(ContextKey.SNAPSHOT_SKIP_VALIDATION, false);
+		setValue(ContextKey.SNAPSHOT_WATCHER, false);
 		setValue(ContextKey.LOCAL_MODE, false);
 		setValue(ContextKey.CHECK_SWITCHERS, false);
 		setValue(ContextKey.RESTRICT_RELAY, true);
 	}
 
 	@Override
 	public void loadFromProperties(Properties prop) {
-		setValue(ContextKey.CONTEXT_LOCATION, SwitcherUtils.resolveProperties(ContextKey.CONTEXT_LOCATION.getParam(), prop));
-		setValue(ContextKey.URL, SwitcherUtils.resolveProperties(ContextKey.URL.getParam(), prop));
-		setValue(ContextKey.APIKEY, SwitcherUtils.resolveProperties(ContextKey.APIKEY.getParam(), prop));
-		setValue(ContextKey.DOMAIN, SwitcherUtils.resolveProperties(ContextKey.DOMAIN.getParam(), prop));
-		setValue(ContextKey.COMPONENT, SwitcherUtils.resolveProperties(ContextKey.COMPONENT.getParam(), prop));
-		setValue(ContextKey.ENVIRONMENT, getValueDefault(SwitcherUtils.resolveProperties(ContextKey.ENVIRONMENT.getParam(), prop), DEFAULT_ENV));
-		setValue(ContextKey.SNAPSHOT_LOCATION, SwitcherUtils.resolveProperties(ContextKey.SNAPSHOT_LOCATION.getParam(), prop));
-		setValue(ContextKey.SNAPSHOT_SKIP_VALIDATION, getBoolDefault(SwitcherUtils.resolveProperties(ContextKey.SNAPSHOT_SKIP_VALIDATION.getParam(), prop), false));
-		setValue(ContextKey.SNAPSHOT_AUTO_LOAD, getBoolDefault(SwitcherUtils.resolveProperties(ContextKey.SNAPSHOT_AUTO_LOAD.getParam(), prop), false));
-		setValue(ContextKey.SNAPSHOT_AUTO_UPDATE_INTERVAL, SwitcherUtils.resolveProperties(ContextKey.SNAPSHOT_AUTO_UPDATE_INTERVAL.getParam(), prop));
-		setValue(ContextKey.SILENT_MODE, SwitcherUtils.resolveProperties(ContextKey.SILENT_MODE.getParam(), prop));
-		setValue(ContextKey.LOCAL_MODE, getBoolDefault(SwitcherUtils.resolveProperties(ContextKey.LOCAL_MODE.getParam(), prop), false));
-		setValue(ContextKey.CHECK_SWITCHERS, getBoolDefault(SwitcherUtils.resolveProperties(ContextKey.CHECK_SWITCHERS.getParam(), prop), false));
-		setValue(ContextKey.RESTRICT_RELAY, getBoolDefault(SwitcherUtils.resolveProperties(ContextKey.RESTRICT_RELAY.getParam(), prop), true));
-		setValue(ContextKey.REGEX_TIMEOUT, getIntDefault(SwitcherUtils.resolveProperties(ContextKey.REGEX_TIMEOUT.getParam(), prop), DEFAULT_REGEX_TIMEOUT));
-		setValue(ContextKey.TRUSTSTORE_PATH, SwitcherUtils.resolveProperties(ContextKey.TRUSTSTORE_PATH.getParam(), prop));
-		setValue(ContextKey.TRUSTSTORE_PASSWORD, SwitcherUtils.resolveProperties(ContextKey.TRUSTSTORE_PASSWORD.getParam(), prop));
-		setValue(ContextKey.TIMEOUT_MS, getIntDefault(SwitcherUtils.resolveProperties(ContextKey.TIMEOUT_MS.getParam(), prop), DEFAULT_TIMEOUT));
-		setValue(ContextKey.POOL_CONNECTION_SIZE, getIntDefault(SwitcherUtils.resolveProperties(ContextKey.POOL_CONNECTION_SIZE.getParam(), prop), DEFAULT_POOL_SIZE));
+		setValue(ContextKey.CONTEXT_LOCATION, resolveProperties(ContextKey.CONTEXT_LOCATION.getParam(), prop));
+		setValue(ContextKey.URL, resolveProperties(ContextKey.URL.getParam(), prop));
+		setValue(ContextKey.APIKEY, resolveProperties(ContextKey.APIKEY.getParam(), prop));
+		setValue(ContextKey.DOMAIN, resolveProperties(ContextKey.DOMAIN.getParam(), prop));
+		setValue(ContextKey.COMPONENT, resolveProperties(ContextKey.COMPONENT.getParam(), prop));
+		setValue(ContextKey.ENVIRONMENT, getValueDefault(resolveProperties(ContextKey.ENVIRONMENT.getParam(), prop), DEFAULT_ENV));
+		setValue(ContextKey.SNAPSHOT_LOCATION, resolveProperties(ContextKey.SNAPSHOT_LOCATION.getParam(), prop));
+		setValue(ContextKey.SNAPSHOT_SKIP_VALIDATION, getBoolDefault(resolveProperties(ContextKey.SNAPSHOT_SKIP_VALIDATION.getParam(), prop), false));
+		setValue(ContextKey.SNAPSHOT_AUTO_LOAD, getBoolDefault(resolveProperties(ContextKey.SNAPSHOT_AUTO_LOAD.getParam(), prop), false));
+		setValue(ContextKey.SNAPSHOT_AUTO_UPDATE_INTERVAL, resolveProperties(ContextKey.SNAPSHOT_AUTO_UPDATE_INTERVAL.getParam(), prop));
+		setValue(ContextKey.SNAPSHOT_WATCHER, getBoolDefault(resolveProperties(ContextKey.SNAPSHOT_WATCHER.getParam(), prop), false));
+		setValue(ContextKey.SILENT_MODE, resolveProperties(ContextKey.SILENT_MODE.getParam(), prop));
+		setValue(ContextKey.LOCAL_MODE, getBoolDefault(resolveProperties(ContextKey.LOCAL_MODE.getParam(), prop), false));
+		setValue(ContextKey.CHECK_SWITCHERS, getBoolDefault(resolveProperties(ContextKey.CHECK_SWITCHERS.getParam(), prop), false));
+		setValue(ContextKey.RESTRICT_RELAY, getBoolDefault(resolveProperties(ContextKey.RESTRICT_RELAY.getParam(), prop), true));
+		setValue(ContextKey.REGEX_TIMEOUT, getIntDefault(resolveProperties(ContextKey.REGEX_TIMEOUT.getParam(), prop), DEFAULT_REGEX_TIMEOUT));
+		setValue(ContextKey.TRUSTSTORE_PATH, resolveProperties(ContextKey.TRUSTSTORE_PATH.getParam(), prop));
+		setValue(ContextKey.TRUSTSTORE_PASSWORD, resolveProperties(ContextKey.TRUSTSTORE_PASSWORD.getParam(), prop));
+		setValue(ContextKey.TIMEOUT_MS, getIntDefault(resolveProperties(ContextKey.TIMEOUT_MS.getParam(), prop), DEFAULT_TIMEOUT));
+		setValue(ContextKey.POOL_CONNECTION_SIZE, getIntDefault(resolveProperties(ContextKey.POOL_CONNECTION_SIZE.getParam(), prop), DEFAULT_POOL_SIZE));
 	}
 
 	@Override

src/main/java/com/github/switcherapi/client/model/ContextKey.java

@@ -58,6 +58,11 @@ public enum ContextKey {
 	 * (String) Interval given to the library to update the snapshot
 	 */
 	SNAPSHOT_AUTO_UPDATE_INTERVAL("switcher.snapshot.updateinterval"),
+
+	/**
+	 * (boolean) Defines if the client will watch the snapshot file for changes and update the switchers accordingly. (default is false)
+	 */
+	SNAPSHOT_WATCHER("switcher.snapshot.watcher"),
 
 	/**
 	 * (String) Defines if client will work in silent mode by specifying the time interval to retry

src/test/java/com/github/switcherapi/client/utils/SnapshotTest.java

@@ -0,0 +1,77 @@
+package com.github.switcherapi.client.utils;
+
+import com.github.switcherapi.SwitchersBase;
+import com.github.switcherapi.client.model.criteria.Data;
+import com.github.switcherapi.client.model.criteria.Domain;
+import com.github.switcherapi.client.model.criteria.Snapshot;
+import com.github.switcherapi.client.service.WorkerName;
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import org.apache.commons.lang3.StringUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.BufferedWriter;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+abstract class SnapshotTest {
+
+	private static final Logger logger = LoggerFactory.getLogger(SnapshotTest.class);
+
+	protected static final String SNAPSHOTS_LOCAL = Paths.get(StringUtils.EMPTY).toAbsolutePath() + "/src/test/resources";
+
+	protected static void removeGeneratedFiles() throws IOException {
+		SwitchersBase.stopWatchingSnapshot();
+		Files.deleteIfExists(Paths.get(SNAPSHOTS_LOCAL + "\\generated_watcher_default.json"));
+	}
+
+	protected static void generateFixture() {
+		final Snapshot mockedSnapshot = new Snapshot();
+		final Data data = new Data();
+		data.setDomain(SnapshotLoader.loadSnapshot(SNAPSHOTS_LOCAL + "/snapshot_watcher.json"));
+		mockedSnapshot.setData(data);
+
+		SnapshotLoader.saveSnapshot(mockedSnapshot, SNAPSHOTS_LOCAL, "generated_watcher_default");
+	}
+
+	protected void changeFixture() {
+		final Snapshot mockedSnapshot = new Snapshot();
+		final Data data = new Data();
+		data.setDomain(SnapshotLoader.loadSnapshot(SNAPSHOTS_LOCAL + "/snapshot_watcher.json"));
+		mockedSnapshot.setData(data);
+
+		data.setDomain(new Domain(
+				data.getDomain().getName(),
+				data.getDomain().getDescription(),
+				!data.getDomain().isActivated(),
+				data.getDomain().getVersion(),
+				data.getDomain().getGroup()));
+
+		final Gson gson = new GsonBuilder().setPrettyPrinting().create();
+		writeFixture(gson.toJson(mockedSnapshot));
+	}
+
+	protected void writeFixture(String content) {
+		try (
+				final FileWriter fileWriter = new FileWriter(
+						String.format("%s/%s.json", SNAPSHOTS_LOCAL, "generated_watcher_default"));
+
+				final BufferedWriter bw = new BufferedWriter(fileWriter);
+				final PrintWriter wr = new PrintWriter(bw)) {
+			wr.write(content);
+		} catch (Exception e) {
+			logger.error(e.getMessage(), e);
+		}
+	}
+
+	protected void assertWorker(boolean exists) {
+		assertEquals(exists, Thread.getAllStackTraces().keySet().stream()
+				.anyMatch(t -> t.getName().equals(WorkerName.SNAPSHOT_WATCH_WORKER.toString())));
+	}
+}