[dynamic control] Move to using SourceWrapper, simplifying parsing (#2708)

Author: jackshirazi

dynamic-control/src/main/java/io/opentelemetry/contrib/dynamic/policy/AbstractSourcePolicyValidator.java

@@ -0,0 +1,100 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.contrib.dynamic.policy;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import io.opentelemetry.contrib.dynamic.policy.source.JsonSourceWrapper;
+import io.opentelemetry.contrib.dynamic.policy.source.KeyValueSourceWrapper;
+import io.opentelemetry.contrib.dynamic.policy.source.SourceFormat;
+import io.opentelemetry.contrib.dynamic.policy.source.SourceWrapper;
+import javax.annotation.Nullable;
+
+/** Base validator with common source-dispatch and parse helpers. */
+public abstract class AbstractSourcePolicyValidator implements PolicyValidator {
+
+  @Override
+  @Nullable
+  public final TelemetryPolicy validate(SourceWrapper source) {
+    if (source == null) {
+      return null;
+    }
+    SourceFormat format = source.getFormat();
+    switch (format) {
+      case JSON: // transitional: same payload shape as JSONKEYVALUE until JSON is removed
+      case JSONKEYVALUE:
+        return validateJsonSource(((JsonSourceWrapper) source).asJsonNode());
+      case KEYVALUE:
+        return validateKeyValueSource((KeyValueSourceWrapper) source);
+    }
+    return null;
+  }
+
+  @Nullable
+  private TelemetryPolicy validateJsonSource(JsonNode node) {
+    JsonNode valueNode = node.get(getPolicyType());
+    if (valueNode == null) {
+      return null;
+    }
+    return validateJsonValue(valueNode);
+  }
+
+  @Nullable
+  private TelemetryPolicy validateKeyValueSource(KeyValueSourceWrapper source) {
+    if (!getPolicyType().equals(source.getKey().trim())) {
+      return null;
+    }
+    return validateKeyValueValue(source.getValue());
+  }
+
+  @Nullable
+  protected abstract TelemetryPolicy validateJsonValue(JsonNode valueNode);
+
+  @Nullable
+  protected abstract TelemetryPolicy validateKeyValueValue(String value);
+
+  @Nullable
+  protected static Double parseDouble(JsonNode valueNode) {
+    if (valueNode.isNumber()) {
+      return valueNode.asDouble();
+    }
+    if (valueNode.isTextual()) {
+      return parseDouble(valueNode.asText());
+    }
+    return null;
+  }
+
+  @Nullable
+  protected static Double parseDouble(String value) {
+    try {
+      return Double.parseDouble(value.trim());
+    } catch (NumberFormatException e) {
+      return null;
+    }
+  }
+
+  @Nullable
+  protected static Boolean parseBoolean(JsonNode valueNode) {
+    if (valueNode.isBoolean()) {
+      return valueNode.asBoolean();
+    }
+    if (valueNode.isTextual()) {
+      return parseBoolean(valueNode.asText());
+    }
+    return null;
+  }
+
+  @Nullable
+  protected static Boolean parseBoolean(String value) {
+    String normalized = value.trim();
+    if ("true".equalsIgnoreCase(normalized)) {
+      return true;
+    }
+    if ("false".equalsIgnoreCase(normalized)) {
+      return false;
+    }
+    return null;
+  }
+}

dynamic-control/src/main/java/io/opentelemetry/contrib/dynamic/policy/LinePerPolicyFileProvider.java

@@ -5,6 +5,8 @@
 
 package io.opentelemetry.contrib.dynamic.policy;
 
+import io.opentelemetry.contrib.dynamic.policy.source.SourceFormat;
+import io.opentelemetry.contrib.dynamic.policy.source.SourceWrapper;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -18,14 +20,13 @@
  * A {@link PolicyProvider} that reads policies from a local file, where each line represents a
  * separate policy configuration.
  *
- * <p>The file format supports two types of lines:
+ * <p>The file format supports JSON and key-value lines:
  *
  * <ul>
  *   <li><b>JSON Objects:</b> Lines starting with <code>{</code> are treated as JSON objects and
  *       validated against the registered {@link PolicyValidator}s.
- *   <li><b>Key-Value Pairs:</b> Lines in the format <code>key=value</code> are treated as aliases,
- *       where the key matches a validator's {@link PolicyValidator#getAlias()} and the value is
- *       parsed accordingly.
+ *   <li><b>Key-Value:</b> Lines containing <code>=</code> are treated as key-value policy lines and
+ *       validated against the registered {@link PolicyValidator}s.
  * </ul>
  *
  * <p>Empty lines and lines starting with <code>#</code> are ignored.
@@ -57,47 +58,33 @@ public List<TelemetryPolicy> fetchPolicies() throws IOException {
               return;
             }
 
-            TelemetryPolicy policy = null;
-
+            SourceFormat format;
             if (trimmedLine.startsWith("{")) {
-              for (PolicyValidator validator : validators) {
-                if (trimmedLine.contains("\"" + validator.getPolicyType() + "\"")) {
-                  policy = validator.validate(trimmedLine);
-                  if (policy != null) {
-                    break;
-                  }
-                }
-              }
+              format = SourceFormat.JSON;
+            } else if (trimmedLine.indexOf('=') >= 0) {
+              format = SourceFormat.KEYVALUE;
             } else {
-              int idx = trimmedLine.indexOf('=');
-              if (idx > 0) {
-                String key = trimmedLine.substring(0, idx).trim();
-                String valueStr = trimmedLine.substring(idx + 1).trim();
+              logger.info("Unsupported policy line format: " + trimmedLine);
+              return;
+            }
+            List<SourceWrapper> parsedSources = format.parse(trimmedLine);
+            if (parsedSources == null || parsedSources.size() != 1) {
+              logger.info("Invalid " + format.configValue() + " policy line: " + trimmedLine);
+              return;
+            }
 
-                for (PolicyValidator validator : validators) {
-                  String alias = validator.getAlias();
-                  if (alias != null && alias.equals(key)) {
-                    try {
-                      policy = validator.validateAlias(key, valueStr);
-                    } catch (UnsupportedOperationException e) {
-                      logger.info(
-                          "Validator does not support alias validation: "
-                              + validator.getClass().getName());
-                      continue;
-                    }
-                    if (policy != null) {
-                      break;
-                    }
-                  }
-                }
+            SourceWrapper parsedSource = parsedSources.get(0);
+            TelemetryPolicy policy = null;
+            for (PolicyValidator validator : validators) {
+              policy = validator.validate(parsedSource);
+              if (policy != null) {
+                break;
               }
             }
-
             if (policy == null) {
               logger.info("Validator not found or rejected for line: " + trimmedLine);
               return;
             }
-
             policies.add(policy);
           });
     }