Adding a new proposal based on two flags at the pipelinerun spec leveL.

Adding alternatives solutions.

teps/0047-finallytask-execution-post-timeout.md

@@ -19,6 +19,9 @@ authors:
 - [Proposal](#proposal)
 - [Test Plan](#test-plan)
 - [Alternatives](#alternatives)
+  - [Finally block level timeout flag](#finally-block-level-timeout-flag)
+  - [Pipelinerun timeout is inclusive of the finally tasks timeout](#pipelinerun-timeout-is-inclusive-of-the-finally-tasks-timeout)
+  - [Finally Timeout flag at Pipelinerun Spec](#finally-timeout-flag-at-pipelinerun-spec)
 <!-- /toc -->
 
 ## Summary
@@ -168,24 +171,43 @@ implementation.  The "Design Details" section below is for the real
 nitty-gritty.
 -->
 
-Enable finally task to run when a pipeline times out. This implies a behavioral change, as finally tasks will run no matter what. 
+Enable finally task to run when a pipeline times out.
 
-Enable pipeline authors to specify a timeout field for finally tasks. In all normal run, that timeout is not needed and finally tasks execute after non-finally tasks. But in case of timed out pipeline, the finally task execution is bounded by the declared timeout.
+We propose to deprecate the current `timeout` as the pipelinerun level. This timeout is as of today used as the timeout of each newly created taskrun by the controller.
+
+Instead we propose to have to new flags: 
+- tasksTimeout
+- runTimeout
+
+`tasksTimeout` will define a timeout for the dag tasks. `runTimeout` will define a timeout for the whole pipelinerun. The finally tasks timeout willbe `runTimeout - tasksTimeout` with `runTimeout > tasksTimeout`.
+
+When `tasksTimeout` is not defined, `runTimeout` is used for the tasks timeout.
 
+This will enable users to manage run time behavior and make sure their finally tasks run as intended by scoping the tasks runtime period.
+
+.
 ```yaml
 spec:
-  tasks:
+  tasksTimeout: "1h0m0s"
+  runTimeout: "2h0m0s"
+  pipelineSpec:
+    tasks:
     - name: tests
       taskRef:
         Name: integration-test
-  finally:
-    timeout: "0h0m10s"
+    finally:
     - name: cleanup-test
       taskRef:
         Name: cleanup
 ```
 
-In order to keep older declaration working, we set the timeout field optional with a `default 20 minutes timeout`. 
+The default default-timeout-minutes configurable via configmap is kept and will be applied to the `runTimeout`.
+
+In order to keep older declaration working. We will use the [`Feature Flag for all alpha features`](https://github.com/tektoncd/community/pull/280) to enable the new feature.
+
+When we opt-in the feature, we may specify a `tasksTimeout` and a `runTimeout` flags. The will be used to define dags tasks timeout and the pipelinerun timeout. We cannot use the current `timeout` flag. It would result in a validation error.
+
+When we opt-out, the current behaviour is kept. We cannot use `tasksTimeout` and a `runTimeout` flags. It would result in a validation error.
 
 
 ## Test Plan
@@ -215,4 +237,33 @@ not need to be as detailed as the proposal, but should include enough
 information to express the idea and why it was not acceptable.
 -->
 
-We could add a new field to decide whether to permits finally tasks to run in case of timeout.
+### Finally block level timeout flag
+
+Enable finally task to run when a pipeline times out. This implies a behavioral change, as finally tasks will run no matter what. 
+
+Enable pipeline authors to specify a timeout field for finally tasks. In all normal run, that timeout is not needed and finally tasks execute after non-finally tasks. But in case of timed out pipeline, the finally task execution is bounded by the declared timeout.
+
+```yaml
+spec:
+  tasks:
+    - name: tests
+      taskRef:
+        Name: integration-test
+  finally:
+    timeout: "0h0m10s"
+    - name: cleanup-test
+      taskRef:
+        Name: cleanup
+```
+
+This solution is not backward compatible as the finally tasks are currently defined as a list field in the pipelineRunSpec type.
+### Pipelinerun timeout is inclusive of the finally tasks timeout
+
+We could consider that the pipelinerun timeout is inclusive of the finally tasks timeout. So, during execution, we could stop executing dag tasks at some point to give enough time for finally tasks to execute before timing out the pipelinerun (dag tasks timeout = pipelinerun timeout - finally tasks timeout).
+
+This solution was deemed confusing. The user could expect the `timeout` to be for the dag tasks entirely. This is reducing the dagtasks runtime and reduces the user possibilitie sto configure it.
+
+
+### Finally Timeout flag at Pipelinerun Spec
+
+We could add a new flag at the pipelineRun level `finallyTimeout` similar to the timeout flag. If specified, pipelineRun timeout (default is one hour) applies to dag tasks only. The dag tasks will stop executing once it meets the pipelineRun timeout. The finally tasks starts executing at this point and will be executed until meets the timeout specified in finallyTimeout.