feat(SpEL): implement to configure the limit of characters for SpEL expressions

Spring Expression Lanuage (SpEL) has a default limit of 10,000 characters. Springframework provides the feature to configure the limit. This feature allows to configure the limit of characters for SpEL expressions.

Approach:
In order to use an expression with characters more than the given default limit, require to follow either of the below approaches:
1. For Springframework >=5.3.28 and <6.1.3, by setting `maximumExpressionLength` field while instantiating the custom `SpelParserConfiguration` class.
spring-projects/spring-framework#30380
spring-projects/spring-framework#30446

2. For Springframework >=6.1.3, by setting a JVM system property or Spring property named `spring.context.expression.maxLength` to the maximum expression length needed by your application.
spring-projects/spring-framework#31952
spring-projects/spring-framework@7855986

Spinnaker supports spring boot 2.7.18, that brings springframework 5.3.31 [https://docs.spring.io/spring-boot/docs/2.7.18/reference/html/dependency-versions.html#appendix.dependency-versions.propertie9]. So first approach need to be implemented along with spinnaker enhancement to expose the `maximumExpressionLength` field.

Author: j-sandy

echo-pipelinetriggers/src/main/java/com/netflix/spinnaker/echo/config/PipelineTriggerConfiguration.java

@@ -13,6 +13,7 @@
 import com.netflix.spinnaker.fiat.shared.FiatPermissionEvaluator;
 import com.netflix.spinnaker.fiat.shared.FiatStatus;
 import com.netflix.spinnaker.kork.dynamicconfig.DynamicConfigService;
+import com.netflix.spinnaker.kork.expressions.config.ExpressionProperties;
 import com.netflix.spinnaker.retrofit.Slf4jRetrofitLogger;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
@@ -34,7 +35,8 @@
 @EnableConfigurationProperties({
   FiatClientConfigurationProperties.class,
   PipelineCacheConfigurationProperties.class,
-  QuietPeriodIndicatorConfigurationProperties.class
+  QuietPeriodIndicatorConfigurationProperties.class,
+  ExpressionProperties.class
 })
 public class PipelineTriggerConfiguration {
   private OkHttpClientProvider clientProvider;

echo-pipelinetriggers/src/main/java/com/netflix/spinnaker/echo/pipelinetriggers/postprocessors/ExpectedArtifactExpressionEvaluationPostProcessor.java

@@ -6,15 +6,18 @@
 import com.netflix.spinnaker.kork.artifacts.model.ExpectedArtifact;
 import com.netflix.spinnaker.kork.expressions.ExpressionEvaluationSummary;
 import com.netflix.spinnaker.kork.expressions.ExpressionTransform;
+import com.netflix.spinnaker.kork.expressions.config.ExpressionProperties;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.function.Function;
 import java.util.stream.Collectors;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.expression.EvaluationContext;
 import org.springframework.expression.ExpressionParser;
 import org.springframework.expression.ParserContext;
 import org.springframework.expression.common.TemplateParserContext;
+import org.springframework.expression.spel.SpelParserConfiguration;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.expression.spel.support.StandardEvaluationContext;
 import org.springframework.stereotype.Component;
@@ -26,11 +29,18 @@
 @Component
 public class ExpectedArtifactExpressionEvaluationPostProcessor implements PipelinePostProcessor {
   private final ObjectMapper mapper;
-  private final ExpressionParser parser = new SpelExpressionParser();
+  private final ExpressionParser parser;
   private final ParserContext parserContext = new TemplateParserContext("${", "}");
 
-  public ExpectedArtifactExpressionEvaluationPostProcessor(ObjectMapper mapper) {
+  public ExpectedArtifactExpressionEvaluationPostProcessor(
+      ObjectMapper mapper, @Autowired ExpressionProperties expressionProperties) {
     this.mapper = mapper;
+    parser =
+        new SpelExpressionParser(
+            expressionProperties.getMaxExpressionLength() > 0
+                ? new SpelParserConfiguration(
+                    null, null, false, false, 0, expressionProperties.getMaxExpressionLength())
+                : new SpelParserConfiguration());
   }
 
   @Override

echo-pipelinetriggers/src/test/groovy/com/netflix/spinnaker/echo/pipelinetriggers/postprocessors/ExpectedArtifactExpressionEvaluationPostProcessorSpec.groovy

@@ -6,13 +6,14 @@ import com.netflix.spinnaker.echo.model.Trigger
 import com.netflix.spinnaker.echo.test.RetrofitStubs
 import com.netflix.spinnaker.kork.artifacts.model.Artifact
 import com.netflix.spinnaker.kork.artifacts.model.ExpectedArtifact
+import com.netflix.spinnaker.kork.expressions.config.ExpressionProperties
 import spock.lang.Shared
 import spock.lang.Specification
 import spock.lang.Subject
 
 class ExpectedArtifactExpressionEvaluationPostProcessorSpec extends Specification implements RetrofitStubs {
   @Subject
-  def artifactPostProcessor = new ExpectedArtifactExpressionEvaluationPostProcessor(EchoObjectMapper.getInstance())
+  def artifactPostProcessor = new ExpectedArtifactExpressionEvaluationPostProcessor(EchoObjectMapper.getInstance(), new ExpressionProperties())
 
   @Shared
   def trigger = Trigger.builder()

echo-pipelinetriggers/src/test/java/com/netflix/spinnaker/echo/pipelinetriggers/postprocessors/ExpectedArtifactExpressionLengthTest.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright 2024 OpsMx, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.netflix.spinnaker.echo.pipelinetriggers.postprocessors;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import com.netflix.spinnaker.echo.jackson.EchoObjectMapper;
+import com.netflix.spinnaker.echo.model.Pipeline;
+import com.netflix.spinnaker.echo.model.Trigger;
+import com.netflix.spinnaker.kork.artifacts.model.Artifact;
+import com.netflix.spinnaker.kork.artifacts.model.ExpectedArtifact;
+import com.netflix.spinnaker.kork.expressions.config.ExpressionProperties;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicInteger;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.TestPropertySource;
+
+@ContextConfiguration(classes = ExpectedArtifactExpressionLengthTest.class)
+@SpringBootTest
+@EnableConfigurationProperties(ExpressionProperties.class)
+@TestPropertySource(properties = {"expression.max-expression-length=11000"})
+class ExpectedArtifactExpressionLengthTest {
+  @Autowired private ExpressionProperties expressionProperties;
+
+  @Test
+  void customExpressionLength() {
+    String expression = String.format("%s", repeat("T", 10900));
+
+    ExpectedArtifactExpressionEvaluationPostProcessor artifactPostProcessor =
+        new ExpectedArtifactExpressionEvaluationPostProcessor(
+            EchoObjectMapper.getInstance(), expressionProperties);
+
+    Trigger trigger =
+        Trigger.builder()
+            .enabled(true)
+            .type("jenkins")
+            .master("master")
+            .job(expression)
+            .buildNumber(100)
+            .build();
+
+    ExpectedArtifact artifact =
+        ExpectedArtifact.builder()
+            .matchArtifact(
+                Artifact.builder()
+                    .name(
+                        "group:artifact:${trigger['job'] == '"
+                            + expression
+                            + "' ? 'expr-worked' : 'expr-not-worked'}")
+                    .version("${trigger['buildNumber']}")
+                    .type("maven/file")
+                    .build())
+            .id("testId")
+            .build();
+
+    Pipeline inputPipeline =
+        Pipeline.builder()
+            .application("application")
+            .name("name")
+            .id(Integer.toString(new AtomicInteger(1).getAndIncrement()))
+            .trigger(trigger)
+            .expectedArtifacts(List.of(artifact))
+            .build()
+            .withTrigger(trigger);
+
+    Pipeline outputPipeline = artifactPostProcessor.processPipeline(inputPipeline);
+
+    Artifact evaluatedArtifact = outputPipeline.getExpectedArtifacts().get(0).getMatchArtifact();
+
+    assertTrue(evaluatedArtifact.getName().equalsIgnoreCase("group:artifact:expr-worked"));
+  }
+
+  private String repeat(String str, int count) {
+    String res = "";
+    for (int i = 0; i < count; i++) {
+      res += str;
+    }
+    return res;
+  }
+}