fix cannot create empty flow

Author: gy2006

core/src/main/java/com/flowci/core/flow/domain/CreateOption.java

@@ -22,13 +22,17 @@
 import lombok.Data;
 import lombok.experimental.Accessors;
 
+import java.util.Objects;
+
 /**
  * @author yang
  */
 @Data
 @Accessors(chain = true)
 public class CreateOption {
 
+    private static final String TEMPLATE_BLANK = "_blank_";
+
     private String groupName;
 
     @JsonProperty("title")
@@ -40,6 +44,10 @@ public class CreateOption {
     @JsonProperty("yml")
     private String rawYaml;
 
+    public boolean isBlank() {
+        return Objects.equals(templateTitle, TEMPLATE_BLANK);
+    }
+
     public boolean hasGroupName() {
         return StringHelper.hasValue(groupName);
     }

core/src/main/java/com/flowci/core/flow/service/FlowServiceImpl.java

@@ -279,6 +279,10 @@ public void onGitHookEvent(GitHookEvent event) {
     // ====================================================================
 
     private String getYmlContent(CreateOption option) {
+        if (option.isBlank()) {
+            return StringHelper.EMPTY;
+        }
+
         if (option.hasTemplateTitle()) {
             try {
                 return loadYmlFromTemplate(option.getTemplateTitle());

core/src/main/java/com/flowci/core/flow/service/YmlService.java

@@ -56,6 +56,7 @@ public interface YmlService {
     /**
      * Create or update yml for flow
      *
+     * @param yml could be null or empty string
      * @throws com.flowci.exception.ArgumentException if yml string is empty or null
      */
     Yml saveYml(Flow flow, String name, String yml);

core/src/main/java/com/flowci/core/flow/service/YmlServiceImpl.java

@@ -105,10 +105,6 @@ public String getYmlString(String flowId, String name) {
 
     @Override
     public Yml saveYml(Flow flow, String name, String yaml) {
-        if (!StringHelper.hasValue(yaml)) {
-            throw new ArgumentException("YAML content cannot be null or empty");
-        }
-
         FlowNode root = YmlParser.load(yaml);
         NodeTree tree = NodeTree.create(root);
 

tree/src/main/java/com/flowci/tree/YmlParser.java

@@ -18,6 +18,7 @@
 
 import com.flowci.exception.YmlException;
 import com.flowci.tree.yml.FlowYml;
+import com.flowci.util.StringHelper;
 import com.flowci.util.YamlHelper;
 import org.yaml.snakeyaml.Yaml;
 import org.yaml.snakeyaml.error.YAMLException;
@@ -33,9 +34,12 @@ public class YmlParser {
      * Create Node instance from yml
      */
     public static synchronized FlowNode load(String yml) {
-        Yaml yaml = YamlHelper.create(FlowYml.class);
+        if (!StringHelper.hasValue(yml)) {
+            return new FlowNode(DEFAULT_ROOT_NAME);
+        }
 
         try {
+            Yaml yaml = YamlHelper.create(FlowYml.class);
             FlowYml root = yaml.load(yml);
             root.setName(DEFAULT_ROOT_NAME);
             return root.toNode(null);

tree/src/test/java/com/flowci/tree/test/YmlParserTest.java

@@ -47,6 +47,12 @@ public void init() throws IOException {
         content = loadContent("flow.yml");
     }
 
+    @Test
+    public void should_parse_empty_string() {
+        FlowNode node = YmlParser.load("");
+        Assert.assertNotNull(node);
+    }
+
     @Test(expected = YmlException.class)
     public void should_yml_exception_if_name_is_invalid() throws IOException {
         content = loadContent("flow-with-invalid-name.yml");