fix(resources)!: publish_pipeline should be re-created every time

Selectively publishing a pipeline doesn't really work in Terraform due
to race conditions. The pipeline resources are updated atomically
outside of the scope of `publish_pipeline`, therefore it's possible that
states will update even if the publish command fails (paused pipeline,
for example). This causes a situation where no changes are detected, and
thus `publish_pipeline` does not become part of the `plan`.

To fix this, constantly remove the `publish_pipeline` from state every
time `Read()` is called. This will force "re-creation" of the publish
resource such that it will be executed every time. Since the
`ENOCHANGES` error is ignored, this operation becomes idempotent.

BREAKING CHANGE: This removes the required `updated_at` property from
the schema. Users will get an error if `updated_at` is required, so this
is a breaking change.

Ref: LOG-20085

docs/resources/publish_pipeline.md

@@ -78,7 +78,6 @@ module "pipeline" {
 
 resource "mezmo_publish_pipeline" "publisher" {
   pipeline_id = module.pipeline.my_pipeline.id
-  updated_at  = module.pipeline.my_pipeline.updated_at
   depends_on  = [module.pipeline]
 }
 ```
@@ -89,4 +88,3 @@ resource "mezmo_publish_pipeline" "publisher" {
 ### Required
 
 - `pipeline_id` (String) The id of the pipeline to monitor for publishing. Any changes to its components will trigger a publish. This pipeline must be configured in a child module with an `output`.
-- `updated_at` (String) The timestamp of the pipeline's last update. This should always be a reference to the `updated_at` field of the child module's `output` of the pipeline to be pusblished.

examples/resources/mezmo_publish_pipeline/resource.tf

@@ -16,6 +16,5 @@ module "pipeline" {
 
 resource "mezmo_publish_pipeline" "publisher" {
   pipeline_id = module.pipeline.my_pipeline.id
-  updated_at  = module.pipeline.my_pipeline.updated_at
   depends_on  = [module.pipeline]
 }

internal/client/types.go

@@ -67,6 +67,5 @@ type SharedSource struct {
 }
 
 type PublishPipeline struct {
-	PipelineId string     `json:"id"`
-	UpdatedAt  *time.Time `json:"updated_at"`
+	PipelineId string `json:"id"`
 }

internal/provider/models/publish_pipeline.go

@@ -1,8 +1,6 @@
 package models
 
 import (
-	"time"
-
 	"github.com/hashicorp/terraform-plugin-framework/resource/schema"
 	"github.com/hashicorp/terraform-plugin-framework/resource/schema/planmodifier"
 	"github.com/hashicorp/terraform-plugin-framework/resource/schema/stringplanmodifier"
@@ -12,7 +10,6 @@ import (
 
 type PublishPipelineResourceModel struct {
 	PipelineId StringValue `tfsdk:"pipeline_id"`
-	UpdatedAt  StringValue `tfsdk:"updated_at"`
 }
 
 func PublishPipelineResourceSchema() schema.Schema {
@@ -55,34 +52,19 @@ resource "mezmo_pipeline" "my_pipeline" {
 					stringplanmodifier.RequiresReplace(),
 				},
 			},
-			"updated_at": schema.StringAttribute{
-				Description: "The timestamp of the pipeline's last update. This should always " +
-					"be a reference to the `updated_at` field of the child module's `output` of the pipeline " +
-					"to be pusblished.",
-				Required: true,
-				PlanModifiers: []planmodifier.String{
-					stringplanmodifier.RequiresReplace(),
-				},
-			},
 		},
 	}
 }
 
 // From terraform schema/model to a struct for sending to the API
 func PublishPipelineFromModel(plan *PublishPipelineResourceModel) *PublishPipeline {
-	updatedAt, _ := time.Parse(time.RFC3339Nano, plan.UpdatedAt.ValueString())
-
 	publishPipeline := PublishPipeline{
 		PipelineId: plan.PipelineId.ValueString(),
-		UpdatedAt:  &updatedAt,
 	}
 	return &publishPipeline
 }
 
 // From an API response to a terraform model
 func PublishPipelineToModel(plan *PublishPipelineResourceModel, publishPipeline *PublishPipeline) {
 	plan.PipelineId = NewStringValue(publishPipeline.PipelineId)
-	if publishPipeline.UpdatedAt != nil {
-		plan.UpdatedAt = NewStringValue(publishPipeline.UpdatedAt.Format(time.RFC3339Nano))
-	}
 }

internal/provider/publish_pipeline_resource.go

@@ -67,14 +67,7 @@ func (r *PublishPipelineResource) Create(ctx context.Context, req resource.Creat
 		return
 	}
 	publish := PublishPipelineFromModel(&plan)
-
-	// The "trick" here is that we don't actually want to change any of the
-	// values based on the response. The response here will have the most
-	// recent `updated_at` timestamp, but we need it to stay consistent
-	// with the state of the pipeline's `updated_at` timestamp. This way,
-	// we never have the plan values deviate from what's stored in the DB,
-	// and the parent pipeline can trigger another publish when it refreshes
-	// and sees that the `updated_at` timestamp has changed on the server.
+	// Result doesn't matter, in fact it would cause data inconsistencies if we used it.
 	_, err := r.client.PublishPipeline(publish.PipelineId, ctx)
 
 	if err != nil && err.(client.ApiResponseError).Code != "ENOCHANGES" {
@@ -85,7 +78,10 @@ func (r *PublishPipelineResource) Create(ctx context.Context, req resource.Creat
 		return
 	}
 
-	// Set the state to match the values from the parent pipeline
+	// Set the state to satisfy the requirement that the response state be set in this method.
+	// The value of state is not used because it's removed on every `Read()`, but we need to prevent
+	// data inconsistecies between the plan and result. There's no need to instantiate
+	// a model here because it's only `pipeline_id`, so we can just use the `plan` as-is.
 	diags := resp.State.Set(ctx, plan)
 	setDiagnosticsHasError(diags, &resp.Diagnostics)
 }
@@ -99,9 +95,10 @@ func (r *PublishPipelineResource) Metadata(_ context.Context, req resource.Metad
 }
 
 func (r *PublishPipelineResource) Read(ctx context.Context, req resource.ReadRequest, resp *resource.ReadResponse) {
-	// NOT having a `Read` for this resource is imperative to how it functions.
-	// We always want the parent pipeline to control the changing of this resource
-	// via `RequiresReplace`, so we never want to refresh the schema here.
+	// This is the magic. We *always* want the publish to fire, so force it to be re-created on every plan
+	// by removing it from state. Without doing this, the resource might not be selected for a "change" and would
+	// skip publishing most times.
+	resp.State.RemoveResource(ctx)
 }
 
 func (*PublishPipelineResource) Schema(_ context.Context, _ resource.SchemaRequest, resp *resource.SchemaResponse) {

internal/provider/publish_pipeline_resource_test.go

@@ -23,14 +23,13 @@ func TestPublishPipelineResource(t *testing.T) {
 					}
 					resource "mezmo_publish_pipeline" "my_publish_pipeline" {
 						pipeline_id = mezmo_pipeline.my_pipeline.id
-            updated_at = mezmo_pipeline.my_pipeline.updated_at
           }
 					`,
+				ExpectNonEmptyPlan: true, // We always re-create which causes a non-empty plan.
 				Check: resource.ComposeTestCheckFunc(
 					resource.TestCheckResourceAttr("mezmo_pipeline.my_pipeline", "title", "pipeline"),
 					StateHasExpectedValues("mezmo_publish_pipeline.my_publish_pipeline", map[string]any{
 						"pipeline_id": "#mezmo_pipeline.my_pipeline.id",
-						"updated_at":  "#mezmo_pipeline.my_pipeline.updated_at",
 					}),
 				),
 			},
@@ -42,14 +41,13 @@ func TestPublishPipelineResource(t *testing.T) {
 					}
 					resource "mezmo_publish_pipeline" "my_publish_pipeline" {
 						pipeline_id = mezmo_pipeline.my_pipeline.id
-            updated_at = mezmo_pipeline.my_pipeline.updated_at
           }
 					`,
+				ExpectNonEmptyPlan: true,
 				Check: resource.ComposeTestCheckFunc(
 					resource.TestCheckResourceAttr("mezmo_pipeline.my_pipeline", "title", "Updated Pipeline"),
 					StateHasExpectedValues("mezmo_publish_pipeline.my_publish_pipeline", map[string]any{
 						"pipeline_id": "#mezmo_pipeline.my_pipeline.id",
-						"updated_at":  "#mezmo_pipeline.my_pipeline.updated_at",
 					}),
 				),
 			},