Merge pull request #691 from HubSpot/limit-eager-tokens

[Eager Execution] Add max number of eager tokens to store

Author: jasmith-hs

src/main/java/com/hubspot/jinjava/JinjavaConfig.java

@@ -59,6 +59,7 @@ public class JinjavaConfig {
   private final int maxListSize;
   private final int maxMapSize;
   private final int rangeLimit;
+  private final int maxNumEagerTokens;
   private final InterpreterFactory interpreterFactory;
   private TokenScannerSymbols tokenScannerSymbols;
   private final ELResolver elResolver;
@@ -111,6 +112,7 @@ private JinjavaConfig(Builder builder) {
     maxListSize = builder.maxListSize;
     maxMapSize = builder.maxMapSize;
     rangeLimit = builder.rangeLimit;
+    maxNumEagerTokens = builder.maxNumEagerTokens;
     interpreterFactory = builder.interpreterFactory;
     tokenScannerSymbols = builder.tokenScannerSymbols;
     elResolver = builder.elResolver;
@@ -150,6 +152,10 @@ public int getRangeLimit() {
     return rangeLimit;
   }
 
+  public int getMaxNumEagerTokens() {
+    return maxNumEagerTokens;
+  }
+
   public RandomNumberGeneratorStrategy getRandomNumberGeneratorStrategy() {
     return randomNumberGenerator;
   }
@@ -242,6 +248,7 @@ public static class Builder {
     private boolean validationMode = false;
     private long maxStringLength = 0;
     private int rangeLimit = DEFAULT_RANGE_LIMIT;
+    private int maxNumEagerTokens = 1000;
     private InterpreterFactory interpreterFactory = new JinjavaInterpreterFactory();
     private TokenScannerSymbols tokenScannerSymbols = new DefaultTokenScannerSymbols();
     private ELResolver elResolver = JinjavaInterpreterResolver.DEFAULT_RESOLVER_READ_ONLY;
@@ -357,6 +364,11 @@ public Builder withRangeLimit(int rangeLimit) {
       return this;
     }
 
+    public Builder withMaxNumEagerTokens(int maxNumEagerTokens) {
+      this.maxNumEagerTokens = maxNumEagerTokens;
+      return this;
+    }
+
     public Builder withInterperterFactory(InterpreterFactory interperterFactory) {
       this.interpreterFactory = interperterFactory;
       return this;

src/main/java/com/hubspot/jinjava/interpret/Context.java

@@ -365,6 +365,15 @@ public Set<Node> getDeferredNodes() {
   }
 
   public void handleEagerToken(EagerToken eagerToken) {
+    int maxNumEagerTokens = JinjavaInterpreter
+      .getCurrentMaybe()
+      .map(i -> i.getConfig().getMaxNumEagerTokens())
+      .orElse(1000);
+    if (eagerTokens.size() >= maxNumEagerTokens) {
+      throw new DeferredValueException(
+        "Too many Deferred Tokens, max is " + maxNumEagerTokens
+      );
+    }
     eagerTokens.add(eagerToken);
     DeferredValueUtils.findAndMarkDeferredProperties(this, eagerToken);
     if (getParent() != null) {