add TTL

inspectit-ocelot-config/src/main/java/rocks/inspectit/ocelot/config/model/command/AgentCommandSettings.java

@@ -4,6 +4,8 @@
 import lombok.NoArgsConstructor;
 import rocks.inspectit.ocelot.config.model.config.RetrySettings;
 
+import javax.validation.Valid;
+import javax.validation.constraints.AssertFalse;
 import java.net.URL;
 import java.time.Duration;
 
@@ -42,6 +44,11 @@ public class AgentCommandSettings {
      */
     private Duration socketTimeout;
 
+    /**
+     * The TTL - the time to keep an HTTP connection alive
+     */
+    private Duration timeToLive;
+
     /**
      * The used interval for polling commands.
      */
@@ -60,5 +67,14 @@ public class AgentCommandSettings {
     /**
      * Settings how retries are handled regarding fetching an agent command.
      */
+    @Valid
     private RetrySettings retry;
+
+    @AssertFalse(message = "The specified time values should not be negative!")
+    public boolean isNegativeTimeout() {
+        boolean negativeLiveReadTimeout = liveSocketTimeout != null && liveSocketTimeout.isNegative();
+        boolean negativeReadTimeout = socketTimeout != null && socketTimeout.isNegative();
+        boolean negativeTTL = timeToLive != null && timeToLive.isNegative();
+        return negativeLiveReadTimeout || negativeReadTimeout || negativeTTL;
+    }
 }

inspectit-ocelot-config/src/main/java/rocks/inspectit/ocelot/config/model/config/HttpConfigSettings.java

@@ -20,7 +20,7 @@
 public class HttpConfigSettings {
 
     /**
-     * Whether a HTTP property source should be used.
+     * Whether an HTTP property source should be used.
      */
     private boolean enabled;
 
@@ -68,17 +68,23 @@ public class HttpConfigSettings {
      */
     private Duration socketTimeout;
 
+    /**
+     * The TTL - the time to keep an HTTP connection alive
+     */
+    private Duration timeToLive;
+
     /**
      * Settings how retries are handled regarding fetching an HTTP property source.
      */
     @Valid
     private RetrySettings retry;
 
-    @AssertFalse(message = "The specified timeout values should not be negative!")
+    @AssertFalse(message = "The specified time values should not be negative!")
     public boolean isNegativeTimeout() {
         boolean negativeConnectionTimeout = connectionTimeout != null && connectionTimeout.isNegative();
         boolean negativeConnectionRequestTimeout = connectionRequestTimeout != null && connectionRequestTimeout.isNegative();
         boolean negativeReadTimeout = socketTimeout != null && socketTimeout.isNegative();
-        return negativeConnectionTimeout || negativeConnectionRequestTimeout || negativeReadTimeout;
+        boolean negativeTTL = timeToLive != null && timeToLive.isNegative();
+        return negativeConnectionTimeout || negativeConnectionRequestTimeout || negativeReadTimeout || negativeTTL;
     }
 }

inspectit-ocelot-config/src/main/resources/rocks/inspectit/ocelot/config/default/basics.yml

@@ -136,6 +136,8 @@ inspectit:
     socket-timeout: 5s
     # the used interval for polling commands
     polling-interval: 15s
+    # the time to keep an HTTP connection alive
+    time-to-live: 4m
     # the maximum time to run one agent command polling task
     task-timeout: 32m
     # how long the agent will stay in the live mode, before falling back to the normal mode

inspectit-ocelot-core/src/main/java/rocks/inspectit/ocelot/core/command/HttpCommandFetcher.java

@@ -24,6 +24,7 @@
 import java.lang.management.RuntimeMXBean;
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.util.concurrent.TimeUnit;
 
 @Slf4j
 @Component
@@ -78,13 +79,20 @@ private void updateHttpClients() {
         AgentCommandSettings settings = environment.getCurrentConfig().getAgentCommands();
         int timeout = (int) settings.getSocketTimeout().toMillis();
         int liveTimeout = (int) settings.getLiveSocketTimeout().toMillis();
+        int timeToLive = (int) settings.getTimeToLive().toMillis();
 
         RequestConfig normalConfig = RequestConfig.custom().setSocketTimeout(timeout).build();
 
         RequestConfig liveConfig = RequestConfig.custom().setSocketTimeout(liveTimeout).build();
 
-        normalHttpClient = HttpClientBuilder.create().setDefaultRequestConfig(normalConfig).build();
-        liveHttpClient = HttpClientBuilder.create().setDefaultRequestConfig(liveConfig).build();
+        normalHttpClient = HttpClientBuilder.create()
+                .setDefaultRequestConfig(normalConfig)
+                .setConnectionTimeToLive(timeToLive, TimeUnit.MILLISECONDS)
+                .build();
+        liveHttpClient = HttpClientBuilder.create()
+                .setDefaultRequestConfig(liveConfig)
+                .setConnectionTimeToLive(timeToLive, TimeUnit.MILLISECONDS)
+                .build();
     }
 
     /**

inspectit-ocelot-core/src/main/java/rocks/inspectit/ocelot/core/config/propertysources/http/HttpClientHolder.java

@@ -8,6 +8,7 @@
 
 import java.io.IOException;
 import java.time.Duration;
+import java.util.concurrent.TimeUnit;
 
 /**
  * Stores an instance of a {@link CloseableHttpClient} and it's relevant {@link HttpConfigSettings}.
@@ -24,6 +25,8 @@ public class HttpClientHolder {
 
     private Duration socketTimeout;
 
+    private Duration timeToLive;
+
     /**
      * Returns a {@link HttpClient}, which is used for fetching the configuration.
      * If the HTTP settings changed, a new client will be created and the old one will be closed.
@@ -32,39 +35,54 @@ public class HttpClientHolder {
      */
     public CloseableHttpClient getHttpClient(HttpConfigSettings httpSettings) throws IOException {
         if(isUpdated(httpSettings) || httpClient == null) {
-            RequestConfig.Builder configBuilder = RequestConfig.custom();
+            RequestConfig config = getRequestConfig(httpSettings);
+            HttpClientBuilder builder = HttpClientBuilder.create().setDefaultRequestConfig(config);
 
-            if (httpSettings.getConnectionTimeout() != null) {
-                int connectionTimeout = (int) httpSettings.getConnectionTimeout().toMillis();
-                configBuilder = configBuilder.setConnectTimeout(connectionTimeout);
-            }
-            if (httpSettings.getConnectionRequestTimeout() != null) {
-                int connectionRequestTimeout = (int) httpSettings.getConnectionRequestTimeout().toMillis();
-                configBuilder = configBuilder.setConnectionRequestTimeout(connectionRequestTimeout);
+            if (httpSettings.getTimeToLive() != null) {
+                int timeToLive = (int) httpSettings.getTimeToLive().toMillis();
+                builder.setConnectionTimeToLive(timeToLive, TimeUnit.MILLISECONDS);
             }
-            if (httpSettings.getSocketTimeout() != null) {
-                int socketTimeout = (int) httpSettings.getSocketTimeout().toMillis();
-                configBuilder = configBuilder.setSocketTimeout(socketTimeout);
-            }
-
-            RequestConfig config = configBuilder.build();
 
             if (httpClient != null) httpClient.close();
-            httpClient = HttpClientBuilder.create().setDefaultRequestConfig(config).build();
-
+            httpClient = builder.build();
             connectionTimeout = httpSettings.getConnectionTimeout();
             connectionRequestTimeout = httpSettings.getConnectionRequestTimeout();
             socketTimeout = httpSettings.getSocketTimeout();
+            timeToLive = httpSettings.getTimeToLive();
         }
         return httpClient;
     }
 
+    /**
+     * @param httpSettings the current HTTP settings
+     * @return the derived request configuration
+     */
+    private static RequestConfig getRequestConfig(HttpConfigSettings httpSettings) {
+        RequestConfig.Builder configBuilder = RequestConfig.custom();
+
+        if (httpSettings.getConnectionTimeout() != null) {
+            int connectionTimeout = (int) httpSettings.getConnectionTimeout().toMillis();
+            configBuilder = configBuilder.setConnectTimeout(connectionTimeout);
+        }
+        if (httpSettings.getConnectionRequestTimeout() != null) {
+            int connectionRequestTimeout = (int) httpSettings.getConnectionRequestTimeout().toMillis();
+            configBuilder = configBuilder.setConnectionRequestTimeout(connectionRequestTimeout);
+        }
+        if (httpSettings.getSocketTimeout() != null) {
+            int socketTimeout = (int) httpSettings.getSocketTimeout().toMillis();
+            configBuilder = configBuilder.setSocketTimeout(socketTimeout);
+        }
+
+        return configBuilder.build();
+    }
+
     /**
      * @return true, if the provided settings differ from the active settings
      */
     private boolean isUpdated(HttpConfigSettings settings) {
         return settings.getConnectionTimeout() != connectionTimeout ||
                 settings.getConnectionRequestTimeout() != connectionRequestTimeout ||
-                settings.getSocketTimeout() != socketTimeout;
+                settings.getSocketTimeout() != socketTimeout ||
+                settings.getTimeToLive() != timeToLive;
     }
 }