Support json config (#131)

* Support json config

Signed-off-by: Pavol Loffay <[email protected]>

* Simplify

Signed-off-by: Pavol Loffay <[email protected]>

* simplify test

Signed-off-by: Pavol Loffay <[email protected]>

* format

Author: pavolloffay

javaagent-core/src/main/java/org/hypertrace/agent/core/HypertraceConfig.java

@@ -23,10 +23,13 @@
 import com.google.protobuf.Int32Value;
 import com.google.protobuf.StringValue;
 import com.google.protobuf.util.JsonFormat;
+import com.google.protobuf.util.JsonFormat.Parser;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.Reader;
 import org.hypertrace.agent.config.Config.AgentConfig;
 import org.hypertrace.agent.config.Config.DataCapture;
 import org.hypertrace.agent.config.Config.Message;
@@ -100,13 +103,18 @@ static AgentConfig load(String filename) throws IOException {
           String.format("Config file %s either does not exist or cannot be read", configFile));
     }
 
-    InputStream fileInputStream = new FileInputStream(configFile);
-    String json = convertYamlToJson(fileInputStream);
-
     AgentConfig.Builder configBuilder = AgentConfig.newBuilder();
-    JsonFormat.parser().ignoringUnknownFields().merge(json, configBuilder);
-
-    return EnvironmentConfig.applyPropertiesAndEnvVars(applyDefaults(configBuilder)).build();
+    Parser jsonParser = JsonFormat.parser().ignoringUnknownFields();
+    try (InputStream fileInputStream = new FileInputStream(configFile)) {
+      if (filename.toLowerCase().endsWith("json")) {
+        Reader targetReader = new InputStreamReader(fileInputStream);
+        jsonParser.merge(targetReader, configBuilder);
+      } else {
+        String json = convertYamlToJson(fileInputStream);
+        jsonParser.merge(json, configBuilder);
+      }
+      return EnvironmentConfig.applyPropertiesAndEnvVars(applyDefaults(configBuilder)).build();
+    }
   }
 
   private static AgentConfig.Builder applyDefaults(AgentConfig.Builder configBuilder) {

javaagent-core/src/test/java/org/hypertrace/agent/core/HypertraceConfigTest.java

@@ -16,13 +16,17 @@
 
 package org.hypertrace.agent.core;
 
+import com.google.protobuf.util.JsonFormat;
+import java.io.File;
+import java.io.FileOutputStream;
 import java.io.IOException;
 import java.net.URL;
 import java.util.Arrays;
 import org.hypertrace.agent.config.Config.AgentConfig;
 import org.hypertrace.agent.config.Config.PropagationFormat;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 import org.junitpioneer.jupiter.ClearSystemProperty;
 
 public class HypertraceConfigTest {
@@ -66,6 +70,25 @@ public void defaultValues() throws IOException {
   public void config() throws IOException {
     URL resource = getClass().getClassLoader().getResource("config.yaml");
     AgentConfig agentConfig = HypertraceConfig.load(resource.getPath());
+    assertConfig(agentConfig);
+  }
+
+  @Test
+  public void jsonConfig(@TempDir File tempFolder) throws IOException {
+    URL resource = getClass().getClassLoader().getResource("config.yaml");
+    AgentConfig agentConfig = HypertraceConfig.load(resource.getPath());
+
+    String jsonConfig = JsonFormat.printer().print(agentConfig);
+    Assertions.assertTrue(!jsonConfig.contains("value"));
+    File jsonFile = new File(tempFolder, "config.jSon");
+    FileOutputStream fileOutputStream = new FileOutputStream(jsonFile);
+    fileOutputStream.write(jsonConfig.getBytes());
+
+    agentConfig = HypertraceConfig.load(jsonFile.getAbsolutePath());
+    assertConfig(agentConfig);
+  }
+
+  private void assertConfig(AgentConfig agentConfig) {
     Assertions.assertEquals("service", agentConfig.getServiceName().getValue());
     Assertions.assertEquals(
         Arrays.asList(PropagationFormat.B3), agentConfig.getPropagationFormatsList());