Add Step and Sidecar Overrides to TaskRun API

This commit adds TaskRunStepOverrides and TaskRunSidecarOverrides to TaskRun.Spec and
PipelineRun.Spec.PipelineTaskRunSpec, gated behind the "alpha" API flag.
This is part 1 of implementing TEP-0094: Configuring Resource Requirements at Runtime.
https://github.com/tektoncd/community/blob/main/teps/0094-configuring-resources-at-runtime.md

docs/install.md

@@ -404,6 +404,7 @@ Features currently in "alpha" are:
 | [Windows Scripts](./tasks.md#windows-scripts)                                                         | [TEP-0057](https://github.com/tektoncd/community/blob/main/teps/0057-windows-support.md)                    | [v0.28.0](https://github.com/tektoncd/pipeline/releases/tag/v0.28.0) |                             |
 | [Remote Tasks](./taskruns.md#remote-tasks) and [Remote Pipelines](./pipelineruns.md#remote-pipelines) | [TEP-0060](https://github.com/tektoncd/community/blob/main/teps/0060-remote-resolutiond.md)                 |                                                                      |                             |
 | [Debug](./debug.md) | [TEP-0042](https://github.com/tektoncd/community/blob/main/teps/0042-taskrun-breakpoint-on-failure.md) | [v0.26.0](https://github.com/tektoncd/pipeline/releases/tag/v0.26.0) | |
+| [Step and Sidecar Overrides](./taskruns.md#overriding-task-steps-and-sidecars)| [TEP-0094](https://github.com/tektoncd/community/blob/main/teps/0094-specifying-resource-requirements-at-runtime.md)                 |                                                                      |                             |
 
 ## Configuring High Availability
 

docs/pipelineruns.md

@@ -472,6 +472,8 @@ spec:
 ```
 
 If used with this `Pipeline`,  `build-task` will use the task specific `PodTemplate` (where `nodeSelector` has `disktype` equal to `ssd`).
+`PipelineTaskRunSpec` may also contain `StepOverrides` and `SidecarOverrides`; see
+[Overriding `Task` `Steps` and `Sidecars`](./taskruns.md#overriding-task-steps-and-sidecars) for more information.
 
 ### Specifying `Workspaces`
 

docs/taskruns.md

@@ -21,6 +21,7 @@ weight: 300
   - [Specifying a `Pod` template](#specifying-a-pod-template)
   - [Specifying `Workspaces`](#specifying-workspaces)
   - [Specifying `Sidecars`](#specifying-sidecars)
+  - [Overriding `Task` `Steps` and `Sidecars`](#overriding-task-steps-and-sidecars)
   - [Specifying `LimitRange` values](#specifying-limitrange-values)
   - [Configuring the failure timeout](#configuring-the-failure-timeout)
   - [Specifying `ServiceAccount` credentials](#specifying-serviceaccount-credentials)
@@ -306,7 +307,8 @@ spec:
 ### Specifying `Resource` limits
 
 Each Step in a Task can specify its resource requirements. See
-[Defining `Steps`](tasks.md#defining-steps)
+[Defining `Steps`](tasks.md#defining-steps). Resource requirements defined in Steps and Sidecars
+may be overridden by a TaskRun's StepOverrides and SidecarOverrides.
 
 ### Specifying a `Pod` template
 
@@ -399,6 +401,56 @@ inside the `Pod`. Only the above command is affected. The `Pod's` description co
 denotes a "Failed" status and the container statuses correctly denote their exit codes
 and reasons.
 
+### Overriding Task Steps and Sidecars
+
+**([alpha only](https://github.com/tektoncd/pipeline/blob/main/docs/install.md#alpha-features))**
+**Warning: This feature is still under development and is not yet functional. Do not use it.**
+
+A TaskRun can specify `StepOverrides` or `SidecarOverrides` to override Step or Sidecar
+configuration specified in a Task.
+
+For example, given the following Task definition:
+
+```yaml
+apiVersion: tekton.dev/v1beta1
+kind: Task
+metadata:
+  name: image-build-task
+spec:
+  steps:
+    - name: build
+      image: gcr.io/kaniko-project/executor:latest
+  sidecars:
+    - name: logging
+      image: my-logging-image
+```
+
+An example TaskRun definition could look like:
+
+```yaml
+apiVersion: tekton.dev/v1beta1
+kind: TaskRun
+metadata:
+  name: image-build-taskrun
+spec:
+  taskRef:
+    name: image-build-task
+  stepOverrides:
+    - name: build
+      resources:
+        requests:
+          memory: 1Gi
+  sidecarOverrides:
+    - name: logging
+      resources:
+        requests:
+          cpu: 100m
+        limits:
+          cpu: 500m
+```
+`StepOverrides` and `SidecarOverrides` must include the `name` field and may include `resources`.
+No other fields can be overridden.
+
 ### Specifying `LimitRange` values
 
 In order to only consume the bare minimum amount of resources needed to execute one `Step` at a

pkg/apis/pipeline/v1beta1/pipelinerun_types.go

@@ -511,9 +511,11 @@ type PipelineTaskRun struct {
 // PipelineTaskRunSpec  can be used to configure specific
 // specs for a concrete Task
 type PipelineTaskRunSpec struct {
-	PipelineTaskName       string       `json:"pipelineTaskName,omitempty"`
-	TaskServiceAccountName string       `json:"taskServiceAccountName,omitempty"`
-	TaskPodTemplate        *PodTemplate `json:"taskPodTemplate,omitempty"`
+	PipelineTaskName       string                   `json:"pipelineTaskName,omitempty"`
+	TaskServiceAccountName string                   `json:"taskServiceAccountName,omitempty"`
+	TaskPodTemplate        *PodTemplate             `json:"taskPodTemplate,omitempty"`
+	StepOverrides          []TaskRunStepOverride    `json:"stepOverrides,omitempty"`
+	SidecarOverrides       []TaskRunSidecarOverride `json:"sidecarOverrides,omitempty"`
 }
 
 // GetTaskRunSpec returns the task specific spec for a given

pkg/apis/pipeline/v1beta1/pipelinerun_validation.go

@@ -112,6 +112,10 @@ func (ps *PipelineRunSpec) Validate(ctx context.Context) (errs *apis.FieldError)
 		}
 	}
 
+	for idx, trs := range ps.TaskRunSpecs {
+		errs = errs.Also(validateTaskRunSpec(ctx, trs).ViaIndex(idx).ViaField("taskRunSpecs"))
+	}
+
 	return errs
 }
 
@@ -188,3 +192,23 @@ func (ps *PipelineRunSpec) validatePipelineTimeout(timeout time.Duration, errorM
 	}
 	return errs
 }
+
+func validateTaskRunSpec(ctx context.Context, trs PipelineTaskRunSpec) (errs *apis.FieldError) {
+	cfg := config.FromContextOrDefaults(ctx)
+	if cfg.FeatureFlags.EnableAPIFields == config.AlphaAPIFields {
+		if trs.StepOverrides != nil {
+			errs = errs.Also(validateStepOverrides(trs.StepOverrides).ViaField("stepOverrides"))
+		}
+		if trs.SidecarOverrides != nil {
+			errs = errs.Also(validateSidecarOverrides(trs.SidecarOverrides).ViaField("sidecarOverrides"))
+		}
+	} else {
+		if trs.StepOverrides != nil {
+			errs = errs.Also(apis.ErrDisallowedFields("stepOverrides"))
+		}
+		if trs.SidecarOverrides != nil {
+			errs = errs.Also(apis.ErrDisallowedFields("sidecarOverrides"))
+		}
+	}
+	return errs
+}