SUBMARINE-598. Support get environment list from database

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

@@ -204,9 +204,31 @@ public Environment getEnvironment(String name)
    */
   public List<Environment> listEnvironments(String status)
       throws SubmarineRuntimeException {
-    List<Environment> environmentList =
+    List<Environment> envs =
         new ArrayList<Environment>(cachedEnvironments.values());
-    return environmentList;
+
+    if (envs.size() != 0) {
+      return envs;
+    }
+    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));
+          envs.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 details.");
+    }
+    return envs;
   }
 
   private void checkSpec(EnvironmentSpec spec)

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" />