configuration accepted for kakfa

src/config.rs

@@ -22,6 +22,13 @@ pub struct Stream {
 #[derive(Serialize, Deserialize, Debug)]
 pub struct Engine {
    pub name: String,
+   pub kafka: Option<Kafka>,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct Kafka {
+   topic: String,
+   consumer_group: String,
 }
 
 pub fn build_config() -> Result<Config, String> {
@@ -36,9 +43,9 @@ fn build_config_yaml(path: String) -> Result<Config, String> {
    match fs::read_to_string(&path) {
       Ok(buffer) => match serde_yaml::from_str(&buffer) {
          Ok(result) => Ok(result),
-         Err(_) => Err("failed to read ".to_string()+&path.as_str()),
+         Err(err) => Err(err.to_string()),
       },
-      Err(_) => Err("failed to read ".to_string()+&path.as_str()),
+      Err(err) => Err(err.to_string()),
    }
 }
 
@@ -46,10 +53,16 @@ fn build_config_std() -> Config {
    return Config {
       streams: Streams{
          input: Stream {
-            engine: Engine{ name: String::from("stdin") },
+            engine: Engine{
+               name: String::from("stdin"),
+               kafka: None,
+            },
          },
          output: Stream {
-            engine: Engine{ name: String::from("stdout") },
+            engine: Engine{
+               name: String::from("stdout"),
+               kafka: None,
+            },
          },
       },
    };

src/engine.rs

@@ -7,10 +7,23 @@ pub trait InputEngine {
 pub fn build_input_engine(cfg: &Engine) -> Result<Box<dyn InputEngine>, String> {
    match cfg.name.as_str() {
       "stdin" => return Ok(Box::new(InputEngineStdin{})),
+      "kafka" => return build_input_engine_kafka(&cfg),
       _ => return Err("unknown input engine name".to_string() + &cfg.name),
    }
 }
 
+pub fn build_input_engine_kafka(_cfg: &Engine) -> Result<Box<dyn InputEngine>, String> {
+   return Err("not impl".to_string());
+}
+
+struct InputEngineKafka {}
+
+impl InputEngine for InputEngineKafka {
+   fn get(&self) -> Vec<char> {
+      Err("not impl".to_string()).unwrap()
+   }
+}
+
 struct InputEngineStdin {}
 
 impl InputEngine for InputEngineStdin {

src/testdata/config-kafka-to-stdout.yaml

@@ -0,0 +1,11 @@
+streams:
+  input:
+    engine:
+      name: kafka
+      kafka:
+        topic: xyz
+        consumer_group: uvw
+  output:
+    engine:
+      name: stdout
+

src/testdata/config-kinesis-to-kafka.json

@@ -13,7 +13,8 @@
          "engine": {
             "name": "kafka",
             "kafka": {
-               "topic": "topic-name"
+               "topic": "topic-name",
+               "consumer_group": "consumer-group-name"
             }
          }
       }