[rules] Add support for pre-compilation of conditions and actions (#4289)

* ScriptConditionHandler/ScriptActionHandler: Add support for pre-compilation of scripts

Signed-off-by: Florian Hotze <florianh_dev@icloud.com>

bundles/org.openhab.core.automation.module.script/src/main/java/org/openhab/core/automation/module/script/internal/handler/AbstractScriptModuleHandler.java

@@ -18,10 +18,14 @@ import java.util.Map.Entry;
 import java.util.Optional;
 import java.util.UUID;
 
+import javax.script.Compilable;
+import javax.script.CompiledScript;
 import javax.script.ScriptContext;
 import javax.script.ScriptEngine;
+import javax.script.ScriptException;
 
 import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
 import org.openhab.core.automation.Module;
 import org.openhab.core.automation.handler.BaseModuleHandler;
 import org.openhab.core.automation.module.script.ScriptEngineContainer;
@@ -35,6 +39,7 @@ import org.slf4j.LoggerFactory;
  *
  * @author Kai Kreuzer - Initial contribution
  * @author Simon Merschjohann - Initial contribution
+ * @author Florian Hotze - Add support for script pre-compilation
  *
  * @param <T> the type of module the concrete handler can handle
  */
@@ -54,6 +59,7 @@ public abstract class AbstractScriptModuleHandler<T extends Module> extends Base
     private final String engineIdentifier;
 
     private Optional<ScriptEngine> scriptEngine = Optional.empty();
+    private Optional<CompiledScript> compiledScript = Optional.empty();
     private final String type;
     protected final String script;
 
@@ -80,6 +86,34 @@ public abstract class AbstractScriptModuleHandler<T extends Module> extends Base
         }
     }
 
+    /**
+     * Creates the {@link ScriptEngine} and compiles the script if the {@link ScriptEngine} implements
+     * {@link Compilable}.
+     */
+    protected void compileScript() throws ScriptException {
+        if (compiledScript.isPresent()) {
+            return;
+        }
+        if (!scriptEngineManager.isSupported(this.type)) {
+            logger.debug(
+                    "ScriptEngine for language '{}' could not be found, skipping compilation of script for identifier: {}",
+                    type, engineIdentifier);
+            return;
+        }
+        Optional<ScriptEngine> engine = getScriptEngine();
+        if (engine.isPresent()) {
+            ScriptEngine scriptEngine = engine.get();
+            if (scriptEngine instanceof Compilable) {
+                logger.debug("Pre-compiling script of rule with UID '{}'", ruleUID);
+                compiledScript = Optional.ofNullable(((Compilable) scriptEngine).compile(script));
+            } else {
+                logger.error(
+                        "Script engine of rule with UID '{}' does not implement Compilable but claims to support pre-compilation",
+                        module.getId());
+            }
+        }
+    }
+
     @Override
     public void dispose() {
         scriptEngineManager.removeEngine(engineIdentifier);
@@ -169,4 +203,26 @@ public abstract class AbstractScriptModuleHandler<T extends Module> extends Base
             executionContext.removeAttribute(key, ScriptContext.ENGINE_SCOPE);
         }
     }
+
+    /**
+     * Evaluates the passed script with the ScriptEngine.
+     *
+     * @param engine the script engine that is used
+     * @param script the script to evaluate
+     * @return the value returned from the execution of the script
+     */
+    protected @Nullable Object eval(ScriptEngine engine, String script) {
+        try {
+            if (compiledScript.isPresent()) {
+                logger.debug("Executing pre-compiled script of rule with UID '{}'", ruleUID);
+                return compiledScript.get().eval(engine.getContext());
+            }
+            logger.debug("Executing script of rule with UID '{}'", ruleUID);
+            return engine.eval(script);
+        } catch (ScriptException e) {
+            logger.error("Script execution of rule with UID '{}' failed: {}", ruleUID, e.getMessage(),
+                    logger.isDebugEnabled() ? e : null);
+            return null;
+        }
+    }
 }

bundles/org.openhab.core.automation.module.script/src/main/java/org/openhab/core/automation/module/script/internal/handler/ScriptActionHandler.java

@@ -31,6 +31,7 @@ import org.slf4j.LoggerFactory;
  *
  * @author Kai Kreuzer - Initial contribution
  * @author Simon Merschjohann - Initial contribution
+ * @author Florian Hotze - Add support for script pre-compilation
  */
 @NonNullByDefault
 public class ScriptActionHandler extends AbstractScriptModuleHandler<Action> implements ActionHandler {
@@ -61,6 +62,11 @@ public class ScriptActionHandler extends AbstractScriptModuleHandler<Action> imp
         super.dispose();
     }
 
+    @Override
+    public void compile() throws ScriptException {
+        super.compileScript();
+    }
+
     @Override
     public @Nullable Map<String, Object> execute(final Map<String, Object> context) {
         Map<String, Object> resultMap = new HashMap<>();
@@ -71,13 +77,8 @@ public class ScriptActionHandler extends AbstractScriptModuleHandler<Action> imp
 
         getScriptEngine().ifPresent(scriptEngine -> {
             setExecutionContext(scriptEngine, context);
-            try {
-                Object result = scriptEngine.eval(script);
-                resultMap.put("result", result);
-            } catch (ScriptException e) {
-                logger.error("Script execution of rule with UID '{}' failed: {}", ruleUID, e.getMessage(),
-                        logger.isDebugEnabled() ? e : null);
-            }
+            Object result = eval(scriptEngine, script);
+            resultMap.put("result", result);
             resetExecutionContext(scriptEngine, context);
         });
 

bundles/org.openhab.core.automation.module.script/src/main/java/org/openhab/core/automation/module/script/internal/handler/ScriptConditionHandler.java

@@ -30,6 +30,7 @@ import org.slf4j.LoggerFactory;
  *
  * @author Kai Kreuzer - Initial contribution
  * @author Simon Merschjohann - Initial contribution
+ * @author Florian Hotze - Add support for script pre-compilation
  */
 @NonNullByDefault
 public class ScriptConditionHandler extends AbstractScriptModuleHandler<Condition> implements ConditionHandler {
@@ -42,6 +43,11 @@ public class ScriptConditionHandler extends AbstractScriptModuleHandler<Conditio
         super(module, ruleUID, scriptEngineManager);
     }
 
+    @Override
+    public void compile() throws ScriptException {
+        super.compileScript();
+    }
+
     @Override
     public boolean isSatisfied(final Map<String, Object> context) {
         boolean result = false;
@@ -55,18 +61,14 @@ public class ScriptConditionHandler extends AbstractScriptModuleHandler<Conditio
         if (engine.isPresent()) {
             ScriptEngine scriptEngine = engine.get();
             setExecutionContext(scriptEngine, context);
-            try {
-                Object returnVal = scriptEngine.eval(script);
-                if (returnVal instanceof Boolean boolean1) {
-                    result = boolean1;
-                } else {
-                    logger.error("Script of rule with UID '{}' did not return a boolean value, but '{}'", ruleUID,
-                            returnVal);
-                }
-            } catch (ScriptException e) {
-                logger.error("Script execution of rule with UID '{}' failed: {}", ruleUID, e.getMessage(),
-                        logger.isDebugEnabled() ? e : null);
+            Object returnVal = eval(scriptEngine, script);
+            if (returnVal instanceof Boolean boolean1) {
+                result = boolean1;
+            } else {
+                logger.error("Script of rule with UID '{}' did not return a boolean value, but '{}'", ruleUID,
+                        returnVal);
             }
+            resetExecutionContext(scriptEngine, context);
         }
 
         return result;

bundles/org.openhab.core.automation/src/main/java/org/openhab/core/automation/handler/ActionHandler.java

@@ -31,6 +31,14 @@ import org.openhab.core.automation.Trigger;
  */
 @NonNullByDefault
 public interface ActionHandler extends ModuleHandler {
+    /**
+     * Called to compile an {@link Action} of the {@link Rule} when the rule is initialized.
+     *
+     * @throws Exception if the compilation fails
+     */
+    default void compile() throws Exception {
+        // Do nothing by default
+    }
 
     /**
      * Called to execute an {@link Action} of the {@link Rule} when it is needed.

bundles/org.openhab.core.automation/src/main/java/org/openhab/core/automation/handler/ConditionHandler.java

@@ -29,6 +29,14 @@ import org.openhab.core.automation.Trigger;
  */
 @NonNullByDefault
 public interface ConditionHandler extends ModuleHandler {
+    /**
+     * Called to compile the {@link Condition} when the {@link Rule} is initialized.
+     *
+     * @throws Exception if the compilation fails
+     */
+    default void compile() throws Exception {
+        // Do nothing by default
+    }
 
     /**
      * Checks if the Condition is satisfied in the given {@code context}.

bundles/org.openhab.core.automation/src/main/java/org/openhab/core/automation/internal/RuleEngineImpl.java

@@ -110,6 +110,7 @@ import org.slf4j.LoggerFactory;
  * @author Benedikt Niehues - change behavior for unregistering ModuleHandler
  * @author Markus Rathgeb - use a managed rule
  * @author Ana Dimova - new reference syntax: list[index], map["key"], bean.field
+ * @author Florian Hotze - add support for script condition/action compilation
  */
 @Component(immediate = true, service = { RuleManager.class })
 @NonNullByDefault
@@ -819,6 +820,8 @@ public class RuleEngineImpl implements RuleManager, RegistryChangeListener<Modul
      * <ul>
      * <li>Set the module handlers. If there are errors, set the rule status (handler error) and return with error
      * indication.
+     * <li>Compile the conditions and actions. If there are errors, set the rule status (handler error) and return with
+     * indication.
      * <li>Register the rule. Set the rule status and return with success indication.
      * </ul>
      *
@@ -845,6 +848,11 @@ public class RuleEngineImpl implements RuleManager, RegistryChangeListener<Modul
             return false;
         }
 
+        // Compile the conditions and actions and so check if they are valid.
+        if (!compileRule(rule)) {
+            return false;
+        }
+
         // Register the rule and set idle status.
         register(rule);
         setStatus(ruleUID, new RuleStatusInfo(RuleStatus.IDLE));
@@ -862,6 +870,58 @@ public class RuleEngineImpl implements RuleManager, RegistryChangeListener<Modul
         return true;
     }
 
+    /**
+     * Compile the conditions and actions of the given rule.
+     * If there are errors, set the rule status (handler error) and return with indication.
+     *
+     * @param rule the rule whose conditions and actions should be compiled
+     * @return true if compilation succeeded, otherwise false
+     */
+    private boolean compileRule(final WrappedRule rule) {
+        try {
+            compileConditions(rule);
+            compileActions(rule);
+            return true;
+        } catch (Throwable t) {
+            setStatus(rule.getUID(), new RuleStatusInfo(RuleStatus.UNINITIALIZED,
+                    RuleStatusDetail.HANDLER_INITIALIZING_ERROR, t.getMessage()));
+            unregister(rule);
+            return false;
+        }
+    }
+
+    /**
+     * Compile the conditions and actions of the given rule.
+     * If there are errors, set the rule status (handler error).
+     *
+     * @param ruleUID the UID of the rule whose conditions and actions should be compiled
+     */
+    private void compileRule(String ruleUID) {
+        final WrappedRule rule = getManagedRule(ruleUID);
+        if (rule == null) {
+            logger.warn("Failed to compile rule '{}': Invalid Rule UID", ruleUID);
+            return;
+        }
+        synchronized (this) {
+            final RuleStatus ruleStatus = getRuleStatus(ruleUID);
+            if (ruleStatus != null && ruleStatus != RuleStatus.IDLE) {
+                logger.error("Failed to compile rule ‘{}' with status '{}'", ruleUID, ruleStatus.name());
+                return;
+            }
+            // change state to INITIALIZING
+            setStatus(ruleUID, new RuleStatusInfo(RuleStatus.INITIALIZING));
+        }
+        if (!compileRule(rule)) {
+            return;
+        }
+        // change state to IDLE only if the rule has not been DISABLED.
+        synchronized (this) {
+            if (getRuleStatus(ruleUID) == RuleStatus.INITIALIZING) {
+                setStatus(ruleUID, new RuleStatusInfo(RuleStatus.IDLE));
+            }
+        }
+    }
+
     @Override
     public @Nullable RuleStatusInfo getStatusInfo(String ruleUID) {
         final WrappedRule rule = managedRules.get(ruleUID);
@@ -1134,6 +1194,32 @@ public class RuleEngineImpl implements RuleManager, RegistryChangeListener<Modul
         return context;
     }
 
+    /**
+     * This method compiles conditions of the {@link Rule} when they exist.
+     * It is called when the rule is initialized.
+     *
+     * @param rule compiled rule.
+     */
+    private void compileConditions(WrappedRule rule) {
+        final Collection<WrappedCondition> conditions = rule.getConditions();
+        if (conditions.isEmpty()) {
+            return;
+        }
+        for (WrappedCondition wrappedCondition : conditions) {
+            final Condition condition = wrappedCondition.unwrap();
+            ConditionHandler cHandler = wrappedCondition.getModuleHandler();
+            if (cHandler != null) {
+                try {
+                    cHandler.compile();
+                } catch (Throwable t) {
+                    String errMessage = "Failed to pre-compile condition: " + condition.getId() + "(" + t.getMessage()
+                            + ")";
+                    throw new RuntimeException(errMessage, t);
+                }
+            }
+        }
+    }
+
     /**
      * This method checks if all rule's condition are satisfied or not.
      *
@@ -1163,6 +1249,31 @@ public class RuleEngineImpl implements RuleManager, RegistryChangeListener<Modul
         return true;
     }
 
+    /**
+     * This method compiles actions of the {@link Rule} when they exist.
+     * It is called when the rule is initialized.
+     *
+     * @param rule compiled rule.
+     */
+    private void compileActions(WrappedRule rule) {
+        final Collection<WrappedAction> actions = rule.getActions();
+        if (actions.isEmpty()) {
+            return;
+        }
+        for (WrappedAction wrappedAction : actions) {
+            final Action action = wrappedAction.unwrap();
+            ActionHandler aHandler = wrappedAction.getModuleHandler();
+            if (aHandler != null) {
+                try {
+                    aHandler.compile();
+                } catch (Throwable t) {
+                    String errMessage = "Failed to pre-compile action: " + action.getId() + "(" + t.getMessage() + ")";
+                    throw new RuntimeException(errMessage, t);
+                }
+            }
+        }
+    }
+
     /**
      * This method evaluates actions of the {@link Rule} and set their {@link Output}s when they exist.
      *
@@ -1435,7 +1546,7 @@ public class RuleEngineImpl implements RuleManager, RegistryChangeListener<Modul
 
     @Override
     public void onReadyMarkerAdded(ReadyMarker readyMarker) {
-        executeRulesWithStartLevel();
+        compileRules();
     }
 
     @Override
@@ -1443,6 +1554,20 @@ public class RuleEngineImpl implements RuleManager, RegistryChangeListener<Modul
         started = false;
     }
 
+    /**
+     * This method compiles the conditions and actions of all rules. It is called when the rule engine is started.
+     * By compiling when the rule engine is started, we make sure all conditions and actions are compiled, even if their
+     * handlers weren't available when the rule was added to the rule engine.
+     */
+    private void compileRules() {
+        getScheduledExecutor().submit(() -> {
+            ruleRegistry.getAll().forEach(r -> {
+                compileRule(r.getUID());
+            });
+            executeRulesWithStartLevel();
+        });
+    }
+
     private void executeRulesWithStartLevel() {
         getScheduledExecutor().submit(() -> {
             ruleRegistry.getAll().stream() //