Concourse: basic support for 'tags' attribute

vscode-extensions/vscode-concourse/src/main/java/org/springframework/ide/vscode/concourse/PipelineYmlSchema.java

@@ -135,6 +135,7 @@ public class PipelineYmlSchema implements YamlSchema {
 		prop(step, "on_failure", step);
 		prop(step, "ensure", step);
 		prop(step, "attempts", t_strictly_pos_integer);
+		prop(step, "tags", t_strings);
 		
 		YBeanType resource = f.ybean("Resource");
 		prop(resource, "name", t_ne_string);

vscode-extensions/vscode-concourse/src/main/resources/desc/Step/tags.md

@@ -0,0 +1,9 @@
+Perform a step on certain workers.
+
+Any step can be directed at a pool of workers for a given set of tags, by adding the `tags` attribute to it.
+
+	tags: [string]
+
+*Optional. Default* `[]`. The tags by which to match workers.
+
+For example, if `[a, b]` is specified, only workers advertising the `a` and `b` tags (or any others) will be used for running the step.

vscode-extensions/vscode-concourse/src/test/java/org/springframework/ide/vscode/concourse/PipelineYamlEditorTest.java

@@ -106,6 +106,17 @@ public class PipelineYamlEditorTest {
 		editor.assertProblems(
 				"name: git\n  type: git|Expecting a 'Sequence' but found a 'Map'"
 		);
+		
+		editor = harness.newEditor(
+				"jobs:\n" +
+				"- name: a-job\n" +
+				"  plan:\n" +
+				"  - task: a-task\n" +
+				"    tags: a-single-string\n"
+		);
+		editor.assertProblems(
+				"a-single-string|Expecting a 'Sequence'"
+		);
 
 		//TODO: Add more test cases for structural problem?
 	}
@@ -217,6 +228,7 @@ public class PipelineYamlEditorTest {
 				"    output_mapping:\n" +
 				"      map: of-stuff\n" +
 				"    config: some-config\n" +
+				"    tags: [a, b, c]\n"+
 				"    attempts: 10\n" +
 				"    ensure:\n" +
 				"      bogus: bad\n" +
@@ -232,6 +244,7 @@ public class PipelineYamlEditorTest {
 		editor.assertHoverContains("input_mapping", "A map from task input names to concrete names in the build plan");
 		editor.assertHoverContains("output_mapping", "A map from task output names to concrete names");
 		editor.assertHoverContains("config", "Use `config` to inline the task config");
+		editor.assertHoverContains("tags", "Any step can be directed at a pool of workers");
 	}
 
 	@Test