SUBMARINE-598. Support get environment list from database

submarine-server/server-core/src/main/java/org/apache/submarine/server/environment/EnvironmentManager.java

@@ -54,6 +54,8 @@ public class EnvironmentManager {
 
   private final AtomicInteger environmentIdCounter = new AtomicInteger(0);
 
+  private static Boolean readedDB = true;
+
   /**
    * Environment Cache
    */
@@ -206,6 +208,31 @@ public List<Environment> listEnvironments(String status)
       throws SubmarineRuntimeException {
     List<Environment> environmentList =
         new ArrayList<Environment>(cachedEnvironments.values());
+
+    // Is it available in cache?
+    if (this.readedDB == true) {
+      try (SqlSession sqlSession = MyBatisUtil.getSqlSession()) {
+        EnvironmentMapper environmentMapper =
+              sqlSession.getMapper(EnvironmentMapper.class);
+        List<EnvironmentEntity> environmentEntitys = environmentMapper.selectAll();
+        for (EnvironmentEntity environmentEntity : environmentEntitys) {
+          if (environmentEntity != null) {
+            Environment env = new Environment();
+            env.setEnvironmentSpec(new Gson().fromJson(
+                  environmentEntity.getEnvironmentSpec(), EnvironmentSpec.class));
+            env.setEnvironmentId(
+                  EnvironmentId.fromString(environmentEntity.getId()));
+            environmentList.add(env);
+            cachedEnvironments.put(env.getEnvironmentSpec().getName(), env);
+          }
+        }
+      } catch (Exception e) {
+        LOG.error(e.getMessage(), e);
+        throw new SubmarineRuntimeException(Status.BAD_REQUEST.getStatusCode(),
+              "Unable to get the environment list.");
+      }
+    }
+    this.readedDB = false;
     return environmentList;
   }
 

submarine-server/server-core/src/main/java/org/apache/submarine/server/environment/database/mappers/EnvironmentMapper.java

@@ -20,8 +20,12 @@
 
 import org.apache.submarine.server.environment.database.entity.EnvironmentEntity;
 
+import java.util.List;
+
 public interface EnvironmentMapper {
 
+  List<EnvironmentEntity> selectAll();
+
   EnvironmentEntity select(String environmentName);
 
   int insert(EnvironmentEntity environment);

submarine-server/server-core/src/main/resources/org/apache/submarine/database/mappers/EnvironmentMapper.xml

@@ -36,6 +36,12 @@
     id, environment_name, environment_spec, create_by, create_time, update_by, update_time
   </sql>
 
+  <select id="selectAll" parameterType="java.lang.String" resultMap="resultMap">
+    select
+    <include refid="Base_Column_List" />
+    from environment
+  </select>
+
   <select id="select" parameterType="java.lang.String" resultMap="resultMap">
     select
     <include refid="Base_Column_List" />

submarine-server/server-core/src/test/java/org/apache/submarine/server/rest/EnvironmentRestApiTest.java

@@ -124,9 +124,11 @@ public void listEnvironment() {
     Response getEnvResponse = environmentStoreApi.listEnvironment("");
     String entity = (String) getEnvResponse.getEntity();
     JsonResponse jsonResponse = gson.fromJson(entity, JsonResponse.class);
+
+    // environments.length = 2; One is created in this test, one is get from database
     Environment[] environments = gson
         .fromJson(gson.toJson(jsonResponse.getResult()), Environment[].class);
-    assertEquals(1, environments.length);
+    assertEquals(2, environments.length);
 
     Environment environment = environments[0];
     assertEquals("foo", environment.getEnvironmentSpec().getName());