[TEP-0076]Pipeline results support array

docs/pipelines.md

@@ -95,7 +95,7 @@ A `Pipeline` definition supports the following fields:
         a `Task` requires.
         - [`from`](#using-the-from-field) - Indicates the data for a [`PipelineResource`](resources.md)
           originates from the output of a previous `Task`.
-      - [`runAfter`](#using-the-runafter-field) - Indicates that a `Task` should execute after one or more other 
+      - [`runAfter`](#using-the-runafter-field) - Indicates that a `Task` should execute after one or more other
         `Tasks` without output linking.
       - [`retries`](#using-the-retries-field) - Specifies the number of times to retry the execution of a `Task` after
         a failure. Does not apply to execution cancellations.
@@ -109,7 +109,7 @@ A `Pipeline` definition supports the following fields:
   - [`results`](#emitting-results-from-a-pipeline) - Specifies the location to which the `Pipeline` emits its execution
     results.
   - [`description`](#adding-a-description) - Holds an informative description of the `Pipeline` object.
-  - [`finally`](#adding-finally-to-the-pipeline) - Specifies one or more `Tasks` to be executed in parallel after 
+  - [`finally`](#adding-finally-to-the-pipeline) - Specifies one or more `Tasks` to be executed in parallel after
     all other tasks have completed.
     - [`name`](#adding-finally-to-the-pipeline) - the name of this `Task` within the context of this `Pipeline`.
     - [`taskRef`](#adding-finally-to-the-pipeline) - a reference to a `Task` definition.
@@ -174,7 +174,7 @@ spec:
           workspace: pipeline-ws1
 ```
 
-For simplicity you can also map the name of the `Workspace` in `PipelineTask` to match with 
+For simplicity you can also map the name of the `Workspace` in `PipelineTask` to match with
 the `Workspace` from the `Pipeline`.
 For example:
 
@@ -191,12 +191,12 @@ spec:
       taskRef:
         name: gen-code # gen-code expects a Workspace named "source"
       workspaces:
-        - name: source # <- mapping workspace name 
+        - name: source # <- mapping workspace name
     - name: commit
       taskRef:
         name: commit # commit expects a Workspace named "source"
       workspaces:
-        - name: source # <- mapping workspace name 
+        - name: source # <- mapping workspace name
       runAfter:
         - gen-code
 ```
@@ -402,7 +402,7 @@ spec:
 `"true"` in the `feature-flags` configmap, see [`install.md`](./install.md#customizing-the-pipelines-controller-behavior)**
 
 You may also specify your `Task` reference using a `Tekton Bundle`. A `Tekton Bundle` is an OCI artifact that
-contains Tekton resources like `Tasks` which can be referenced within a `taskRef`.  
+contains Tekton resources like `Tasks` which can be referenced within a `taskRef`.
 
 There is currently a hard limit of 20 objects in a bundle.
 
@@ -628,7 +628,7 @@ To guard a `Task` and its dependent Tasks:
 
 ##### Cascade `when` expressions to the specific dependent `Tasks`
 
-Pick and choose which specific dependent `Tasks` to guard as well, and cascade the `when` expressions to those `Tasks`. 
+Pick and choose which specific dependent `Tasks` to guard as well, and cascade the `when` expressions to those `Tasks`.
 
 Taking the use case below, a user who wants to guard `manual-approval` and its dependent `Tasks`:
 
@@ -689,12 +689,12 @@ tasks:
       value: $(tasks.manual-approval.results.approver)
   taskRef:
     name: slack-msg
-```  
+```
 
 ##### Compose using Pipelines in Pipelines
 
-Compose a set of `Tasks` as a unit of execution using `Pipelines` in `Pipelines`, which allows for guarding a `Task` and 
-its dependent `Tasks` (as a sub-`Pipeline`) using `when` expressions. 
+Compose a set of `Tasks` as a unit of execution using `Pipelines` in `Pipelines`, which allows for guarding a `Task` and
+its dependent `Tasks` (as a sub-`Pipeline`) using `when` expressions.
 
 **Note:** `Pipelines` in `Pipelines` is an [experimental feature](https://github.com/tektoncd/experimental/tree/main/pipelines-in-pipelines)
 
@@ -742,7 +742,7 @@ tasks:
         value: $(tasks.manual-approval.results.approver)
     taskRef:
       name: slack-msg
-      
+
 ---
 ## main pipeline
 tasks:
@@ -765,12 +765,12 @@ tasks:
 
 When `when` expressions evaluate to `False`, the `Task` will be skipped and:
 - The ordering-dependent `Tasks` will be executed
-- The resource-dependent `Tasks` (and their dependencies) will be skipped because of missing `Results` from the skipped 
-  parent `Task`. When we add support for [default `Results`](https://github.com/tektoncd/community/pull/240), then the 
-  resource-dependent `Tasks` may be executed if the default `Results` from the skipped parent `Task` are specified. In 
+- The resource-dependent `Tasks` (and their dependencies) will be skipped because of missing `Results` from the skipped
+  parent `Task`. When we add support for [default `Results`](https://github.com/tektoncd/community/pull/240), then the
+  resource-dependent `Tasks` may be executed if the default `Results` from the skipped parent `Task` are specified. In
   addition, if a resource-dependent `Task` needs a file from a guarded parent `Task` in a shared `Workspace`, make sure
-  to handle the execution of the child `Task` in case the expected file is missing from the `Workspace` because the 
-  guarded parent `Task` is skipped. 
+  to handle the execution of the child `Task` in case the expected file is missing from the `Workspace` because the
+  guarded parent `Task` is skipped.
 
 On the other hand, the rest of the `Pipeline` will continue executing.
 
@@ -823,12 +823,12 @@ tasks:
     name: slack-msg
 ```
 
-If `manual-approval` is skipped, execution of its dependent `Tasks` (`slack-msg`, `build-image` and `deploy-image`) 
+If `manual-approval` is skipped, execution of its dependent `Tasks` (`slack-msg`, `build-image` and `deploy-image`)
 would be unblocked regardless:
 - `build-image` and `deploy-image` should be executed successfully
 - `slack-msg` will be skipped because it is missing the `approver` `Result` from `manual-approval`
   - dependents of `slack-msg` would have been skipped too if it had any of them
-  - if `manual-approval` specifies a default `approver` `Result`, such as "None", then `slack-msg` would be executed 
+  - if `manual-approval` specifies a default `approver` `Result`, such as "None", then `slack-msg` would be executed
     ([supporting default `Results` is in progress](https://github.com/tektoncd/community/pull/240))
 
 ### Configuring the failure timeout
@@ -944,7 +944,7 @@ when:
 
 For an end-to-end example, see [`Task` `Results` in a `PipelineRun`](../examples/v1beta1/pipelineruns/task_results_example.yaml).
 
-Note that `when` expressions are whitespace-sensitive.  In particular, when producing results intended for inputs to `when` 
+Note that `when` expressions are whitespace-sensitive.  In particular, when producing results intended for inputs to `when`
 expressions that may include newlines at their close (e.g. `cat`, `jq`), you may wish to truncate them.
 
 ```yaml
@@ -985,6 +985,8 @@ results:
 
 For an end-to-end example, see [`Results` in a `PipelineRun`](../examples/v1beta1/pipelineruns/pipelinerun-results.yaml).
 
+Array results is supported as alpha feature, see [`Array Results` in a `PipelineRun`](../examples/v1beta1/pipelineruns/alpha/pipelinerun-array-results.yaml).
+
 A `Pipeline Result` is not emitted if any of the following are true:
 - A `PipelineTask` referenced by the `Pipeline Result` failed. The `PipelineRun` will also
 have failed.
@@ -1009,9 +1011,9 @@ without getting stuck in an infinite loop.
 This is done using:
 - _resource dependencies_:
   - [`from`](#using-the-from-field) clauses on the [`PipelineResources`](resources.md) used by each `Task`
-  - [`results`](#emitting-results-from-a-pipeline) of one `Task` being passed into `params` or `when` expressions of 
+  - [`results`](#emitting-results-from-a-pipeline) of one `Task` being passed into `params` or `when` expressions of
     another
-    
+
 - _ordering dependencies_:
   - [`runAfter`](#using-the-runafter-field) clauses on the corresponding `Tasks`
 
@@ -1197,7 +1199,7 @@ spec:
           value: "someURL"
       matrix:
         - name: slack-channel
-          value: 
+          value:
           - "foo"
           - "bar"
 ```

examples/v1beta1/pipelineruns/alpha/pipeline-array-results.yaml

@@ -0,0 +1,40 @@
+apiVersion: tekton.dev/v1beta1
+kind: PipelineRun
+metadata:
+  name: pipelinerun-array-indexing-results
+spec:
+  pipelineSpec:
+    tasks:
+      - name: task1
+        taskSpec:
+          results:
+            - name: array-results
+              type: array
+              description: The array results
+          steps:
+            - name: write-array
+              image: bash:latest
+              script: |
+                #!/usr/bin/env bash
+                echo -n "[\"1\",\"2\",\"3\"]" | tee $(results.array-results.path)
+      - name: task2
+        taskSpec:
+          results:
+            - name: array-results
+              type: array
+              description: The array results
+          steps:
+            - name: write-array
+              image: bash:latest
+              script: |
+                #!/usr/bin/env bash
+                echo -n "[\"4\",\"5\",\"6\"]" | tee $(results.array-results.path)
+    results:
+      - name: echo-indexing-array-results
+        type: string
+        description: array element
+        value: $(tasks.task1.results.array-results[1])
+      - name: echo-array-results
+        type: array
+        description: whole array
+        value: $(tasks.task2.results.array-results[*])

pkg/apis/pipeline/v1beta1/param_types.go

@@ -228,7 +228,7 @@ func (arrayOrString *ArrayOrString) applyOrCorrect(stringReplacements map[string
 
 	// trim the head "$(" and the tail ")" or "[*])"
 	// i.e. get "params.name" from "$(params.name)" or "$(params.name[*])"
-	trimedStringVal := strings.TrimSuffix(strings.TrimSuffix(strings.TrimPrefix(stringVal, "$("), ")"), "[*]")
+	trimedStringVal := StripStarVarSubExpression(stringVal)
 
 	// if the stringVal is a reference to a string param
 	if _, ok := stringReplacements[trimedStringVal]; ok {
@@ -250,6 +250,11 @@ func (arrayOrString *ArrayOrString) applyOrCorrect(stringReplacements map[string
 	}
 }
 
+// StripStarVarSubExpression strips "$(target[*])"" to get "target"
+func StripStarVarSubExpression(s string) string {
+	return strings.TrimSuffix(strings.TrimSuffix(strings.TrimPrefix(s, "$("), ")"), "[*]")
+}
+
 // NewArrayOrString creates an ArrayOrString of type ParamTypeString or ParamTypeArray, based on
 // how many inputs are given (>1 input will create an array, not string).
 func NewArrayOrString(value string, values ...string) *ArrayOrString {

pkg/apis/pipeline/v1beta1/pipeline_types.go

@@ -123,12 +123,17 @@ type PipelineResult struct {
 	// Name the given name
 	Name string `json:"name"`
 
+	// Type is the user-specified type of the result.
+	// The possible types are 'string', 'array', and 'object', with 'string' as the default.
+	// 'array' and 'object' types are alpha features.
+	Type ResultsType `json:"type,omitempty"`
+
 	// Description is a human-readable description of the result
 	// +optional
 	Description string `json:"description"`
 
 	// Value the expression used to retrieve the value
-	Value string `json:"value"`
+	Value ArrayOrString `json:"value"`
 }
 
 // PipelineTaskMetadata contains the labels or annotations for an EmbeddedTask

pkg/apis/pipeline/v1beta1/pipeline_validation_test.go

@@ -129,7 +129,7 @@ func TestPipeline_Validate_Success(t *testing.T) {
 				Results: []PipelineResult{{
 					Name:        "pipeline-result",
 					Description: "this is my pipeline result",
-					Value:       "$(tasks.my-task.results.my-result)",
+					Value:       *NewArrayOrString("$(tasks.my-task.results.my-result)"),
 				}},
 			},
 		},
@@ -1143,11 +1143,11 @@ func TestValidatePipelineResults_Success(t *testing.T) {
 	results := []PipelineResult{{
 		Name:        "my-pipeline-result",
 		Description: "this is my pipeline result",
-		Value:       "$(tasks.a-task.results.output)",
+		Value:       *NewArrayOrString("$(tasks.a-task.results.output)"),
 	}, {
 		Name:        "my-pipeline-object-result",
 		Description: "this is my pipeline result",
-		Value:       "$(tasks.a-task.results.gitrepo.commit)",
+		Value:       *NewArrayOrString("$(tasks.a-task.results.gitrepo.commit)"),
 	}}
 	if err := validatePipelineResults(results); err != nil {
 		t.Errorf("Pipeline.validatePipelineResults() returned error for valid pipeline: %s: %v", desc, err)
@@ -1164,7 +1164,7 @@ func TestValidatePipelineResults_Failure(t *testing.T) {
 		results: []PipelineResult{{
 			Name:        "my-pipeline-result",
 			Description: "this is my pipeline result",
-			Value:       "$(tasks.a-task.results.output.key1.extra)",
+			Value:       *NewArrayOrString("$(tasks.a-task.results.output.key1.extra)"),
 		}},
 		expectedError: apis.FieldError{
 			Message: `invalid value: expected all of the expressions [tasks.a-task.results.output.key1.extra] to be result expressions but only [] were`,
@@ -1175,7 +1175,7 @@ func TestValidatePipelineResults_Failure(t *testing.T) {
 		results: []PipelineResult{{
 			Name:        "my-pipeline-result",
 			Description: "this is my pipeline result",
-			Value:       "foo.bar",
+			Value:       *NewArrayOrString("foo.bar"),
 		}},
 		expectedError: apis.FieldError{
 			Message: `invalid value: expected pipeline results to be task result expressions but no expressions were found`,
@@ -1186,7 +1186,7 @@ func TestValidatePipelineResults_Failure(t *testing.T) {
 		results: []PipelineResult{{
 			Name:        "my-pipeline-result",
 			Description: "this is my pipeline result",
-			Value:       "$(foo.bar)",
+			Value:       *NewArrayOrString("$(foo.bar)"),
 		}},
 		expectedError: apis.FieldError{
 			Message: `invalid value: expected pipeline results to be task result expressions but an invalid expressions was found`,

pkg/apis/pipeline/v1beta1/pipelinerun_types.go

@@ -478,7 +478,7 @@ type PipelineRunResult struct {
 	Name string `json:"name"`
 
 	// Value is the result returned from the execution of this PipelineRun
-	Value string `json:"value"`
+	Value ArrayOrString `json:"value"`
 }
 
 // PipelineRunTaskRunStatus contains the name of the PipelineTask for this TaskRun and the TaskRun's Status