feat: add file output(json/csv)

README.md

@@ -40,6 +40,11 @@ java -jar volta-master/target/volta-master-1.0-SNAPSHOT.jar \
   --agent=localhost:7070
 ```
 
+Stats file (optional): `--stats-out=path`
+
+- Ends with `.csv` → header row + CSV lines (`sample` each second + one `final` row).
+- Any other suffix (for example `.jsonl`) → one JSON object per line (serialized `StatsSnapshot`).
+
 Expected output:
 ```
 [RPS: 0 | Success: 0.0% | Avg: 0ms | Errors: 0]

volta-master/pom.xml

@@ -68,6 +68,10 @@
             <artifactId>mockito-junit-jupiter</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.dataformat</groupId>
+            <artifactId>jackson-dataformat-yaml</artifactId>
+        </dependency>
     </dependencies>
 
     <build>

volta-master/src/main/java/com/volta/master/StartupRunner.java

@@ -44,6 +44,7 @@ public void run(ApplicationArguments args) {
 
     agentClient.startTest(masterArgs.agentUrl(), masterArgs.testConfig());
 
-    statsReporter.startReporting(masterArgs.agentUrl(), masterArgs.testConfig().duration());
+    statsReporter.startReporting(
+        masterArgs.agentUrl(), masterArgs.testConfig().duration(), masterArgs.outputFile());
   }
 }

volta-master/src/main/java/com/volta/master/cli/ArgsParser.java

@@ -1,28 +1,83 @@
 package com.volta.master.cli;
 
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
 import com.volta.model.TestConfig;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Optional;
 import org.springframework.boot.ApplicationArguments;
 
 public class ArgsParser {
 
   private static final String USAGE =
       """
-      Usage:   java -jar volta-master.jar --url=<url> --rps=<rps> --duration=<seconds> --agent=<host:port>
-      Example: java -jar volta-master.jar --url=https://httpbin.org/get --rps=10 --duration=30 --agent=localhost:7070
-      """;
+              Usage:   java -jar volta-master.jar --url=<url> --rps=<rps> --duration=<seconds> --agent=<host:port>
+                       java -jar volta-master.jar --config=./<config.json(.yaml/.yml)> --agent=<host:port>
+
+              Example: java -jar volta-master.jar --url=https://httpbin.org/get --rps=10 --duration=30 --agent=localhost:7070
+                       java -jar volta-master.jar --config=./config.json --agent=localhost:7070 [--stats-out=report.jsonl|report.csv]
+              """;
 
   public static MasterArgs parse(ApplicationArguments args) {
-    String url = requireString(args, "url");
-    int rps = requirePositiveInt(args, "rps");
-    int duration = requirePositiveInt(args, "duration");
-    String agent = requireString(args, "agent");
 
-    validateUrl(url);
+    TestConfig testConfig;
+    if (args.containsOption("config")) {
+      String configPath = requireString(args, "config");
+
+      Path path = Path.of(configPath);
+      if (!Files.exists(path)) {
+        throw new ArgsException("Config file not found: " + configPath + "\n" + USAGE);
+      }
+      if (!Files.isRegularFile(path)) {
+        throw new ArgsException("Config path is not a regular file: " + configPath + "\n" + USAGE);
+      }
+
+      ObjectMapper mapper;
+      String name = path.getFileName().toString().toLowerCase();
+      if (name.endsWith(".json")) {
+        mapper = new ObjectMapper();
+      } else if (name.endsWith(".yaml") || name.endsWith(".yml")) {
+        mapper = new ObjectMapper(new YAMLFactory());
+      } else {
+        throw new ArgsException("Unsupported file format: " + configPath + "\n" + USAGE);
+      }
+
+      try {
+        testConfig = mapper.readValue(path.toFile(), TestConfig.class);
+      } catch (IOException e) {
+        throw new ArgsException(
+            "Failed to read/parse config: " + configPath + "\n" + e.getMessage() + "\n" + USAGE);
+      }
+
+      if (testConfig.rps() <= 0) {
+        throw new ArgsException("Argument rps in config must be positive\n" + USAGE);
+      }
+      if (testConfig.duration() <= 0) {
+        throw new ArgsException("Argument duration in config must be positive\n" + USAGE);
+      }
+      validateUrl(testConfig.url());
+
+    } else {
+      String url = requireString(args, "url");
+      int rps = requirePositiveInt(args, "rps");
+      int duration = requirePositiveInt(args, "duration");
+
+      validateUrl(url);
+      testConfig = new TestConfig(url, rps, duration);
+    }
+    String agent = requireString(args, "agent");
     validateAgent(agent);
 
     agent = "http://" + agent;
 
-    return new MasterArgs(new TestConfig(url, rps, duration), agent);
+    if (args.containsOption("stats-out")) {
+      String outputFile = requireString(args, "stats-out");
+      return new MasterArgs(testConfig, Optional.of(outputFile), agent);
+    }
+
+    return new MasterArgs(testConfig, Optional.empty(), agent);
   }
 
   private static String requireString(ApplicationArguments args, String name) {

volta-master/src/main/java/com/volta/master/cli/MasterArgs.java

@@ -1,5 +1,6 @@
 package com.volta.master.cli;
 
 import com.volta.model.TestConfig;
+import java.util.Optional;
 
-public record MasterArgs(TestConfig testConfig, String agentUrl) {}
+public record MasterArgs(TestConfig testConfig, Optional<String> outputFile, String agentUrl) {}