feat: added json and yaml parsing

README.md

@@ -32,6 +32,36 @@ Agent started on port 7070
 
 ### 3. Run the Master (Terminal 2)
 
+#### Option A (recommended): run from config file
+
+Create a config file (JSON/YAML). Example `config.json`:
+
+```json
+{
+  "url": "https://httpbin.org/get",
+  "rps": 5,
+  "duration": 10
+}
+```
+
+Or `config.yaml`:
+
+```yaml
+url: "https://httpbin.org/get"
+rps: 5
+duration: 10
+```
+
+Run:
+
+```bash
+java -jar volta-master/target/volta-master-1.0-SNAPSHOT.jar \
+  --config=./config.json \
+  --agent=localhost:7070
+```
+
+#### Option B (legacy, still supported): pass parameters via CLI flags
+
 ```bash
 java -jar volta-master/target/volta-master-1.0-SNAPSHOT.jar \
   --url=https://httpbin.org/get \

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/cli/ArgsParser.java

@@ -1,28 +1,77 @@
 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 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
+          """;
 
   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);
+    return new MasterArgs(testConfig, agent);
   }
 
   private static String requireString(ApplicationArguments args, String name) {

volta-master/src/test/java/com/volta/master/cli/ArgsParserTest.java

@@ -3,15 +3,25 @@
 import static org.junit.jupiter.api.Assertions.*;
 
 import com.volta.model.TestConfig;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 import org.springframework.boot.DefaultApplicationArguments;
 
-class CliArgsParserTest {
+class ArgsParserTest {
 
   private static DefaultApplicationArguments args(String... rawArgs) {
     return new DefaultApplicationArguments(rawArgs);
   }
 
+  private static Path writeTempFile(Path dir, String fileName, String content) throws IOException {
+    Path path = dir.resolve(fileName);
+    Files.writeString(path, content);
+    return path;
+  }
+
   @Test
   void validArgsProduceCorrectMasterArgs() {
     MasterArgs result =
@@ -29,6 +39,159 @@ void validArgsProduceCorrectMasterArgs() {
     assertEquals("http://localhost:7070", result.agentUrl());
   }
 
+  @Test
+  void configJsonProducesCorrectMasterArgs(@TempDir Path tempDir) throws Exception {
+    Path configPath =
+        writeTempFile(
+            tempDir,
+            "config.json",
+            """
+            {
+              "url": "https://httpbin.org/get",
+              "rps": 10,
+              "duration": 30
+            }
+            """);
+
+    MasterArgs result =
+        ArgsParser.parse(args("--config=" + configPath.toString(), "--agent=localhost:7070"));
+
+    TestConfig config = result.testConfig();
+    assertEquals("https://httpbin.org/get", config.url());
+    assertEquals(10, config.rps());
+    assertEquals(30, config.duration());
+    assertEquals("http://localhost:7070", result.agentUrl());
+  }
+
+  @Test
+  void missingConfigFileThrows() {
+    assertThrows(
+        ArgsException.class,
+        () ->
+            ArgsParser.parse(
+                args("--config=./definitely-not-exists.json", "--agent=localhost:7070")));
+  }
+
+  @Test
+  void invalidJsonInConfigThrows(@TempDir Path tempDir) throws Exception {
+    Path configPath = writeTempFile(tempDir, "config.json", "{ this is not json }");
+
+    assertThrows(
+        ArgsException.class,
+        () ->
+            ArgsParser.parse(args("--config=" + configPath.toString(), "--agent=localhost:7070")));
+  }
+
+  @Test
+  void zeroRpsInConfigThrows(@TempDir Path tempDir) throws Exception {
+    Path configPath =
+        writeTempFile(
+            tempDir,
+            "config.json",
+            """
+            { "url": "https://example.com", "rps": 0, "duration": 10 }
+            """);
+
+    assertThrows(
+        ArgsException.class,
+        () ->
+            ArgsParser.parse(args("--config=" + configPath.toString(), "--agent=localhost:7070")));
+  }
+
+  @Test
+  void zeroDurationInConfigThrows(@TempDir Path tempDir) throws Exception {
+    Path configPath =
+        writeTempFile(
+            tempDir,
+            "config.json",
+            """
+            { "url": "https://example.com", "rps": 10, "duration": 0 }
+            """);
+
+    assertThrows(
+        ArgsException.class,
+        () ->
+            ArgsParser.parse(args("--config=" + configPath.toString(), "--agent=localhost:7070")));
+  }
+
+  @Test
+  void urlWithoutProtocolInConfigThrows(@TempDir Path tempDir) throws Exception {
+    Path configPath =
+        writeTempFile(
+            tempDir,
+            "config.json",
+            """
+            { "url": "example.com", "rps": 10, "duration": 10 }
+            """);
+
+    assertThrows(
+        ArgsException.class,
+        () ->
+            ArgsParser.parse(args("--config=" + configPath.toString(), "--agent=localhost:7070")));
+  }
+
+  @Test
+  void configYamlProducesCorrectMasterArgs(@TempDir Path tempDir) throws Exception {
+    Path configPath =
+        writeTempFile(
+            tempDir,
+            "config.yaml",
+            """
+            url: "https://httpbin.org/get"
+            rps: 10
+            duration: 30
+            """);
+
+    MasterArgs result =
+        ArgsParser.parse(args("--config=" + configPath.toString(), "--agent=localhost:7070"));
+
+    TestConfig config = result.testConfig();
+    assertEquals("https://httpbin.org/get", config.url());
+    assertEquals(10, config.rps());
+    assertEquals(30, config.duration());
+    assertEquals("http://localhost:7070", result.agentUrl());
+  }
+
+  @Test
+  void configYmlProducesCorrectMasterArgs(@TempDir Path tempDir) throws Exception {
+    Path configPath =
+        writeTempFile(
+            tempDir,
+            "config.yml",
+            """
+            url: "https://httpbin.org/get"
+            rps: 10
+            duration: 30
+            """);
+
+    MasterArgs result =
+        ArgsParser.parse(args("--config=" + configPath.toString(), "--agent=localhost:7070"));
+
+    TestConfig config = result.testConfig();
+    assertEquals("https://httpbin.org/get", config.url());
+    assertEquals(10, config.rps());
+    assertEquals(30, config.duration());
+    assertEquals("http://localhost:7070", result.agentUrl());
+  }
+
+  @Test
+  void unsupportedConfigExtensionThrows(@TempDir Path tempDir) throws Exception {
+    Path configPath =
+        writeTempFile(
+            tempDir,
+            "config.txt",
+            """
+            url=https://example.com
+            rps=10
+            duration=30
+            """);
+
+    assertThrows(
+        ArgsException.class,
+        () ->
+            ArgsParser.parse(args("--config=" + configPath.toString(), "--agent=localhost:7070")));
+  }
+
   @Test
   void httpUrlIsAccepted() {
     assertDoesNotThrow(