Rework workflow release content description (#49)

Author: lukasbindreiter

apis/workflows/v1/task_release.proto

@@ -0,0 +1,40 @@
+edition = "2023";
+
+package workflows.v1;
+
+import "buf/validate/validate.proto";
+import "google/protobuf/empty.proto";
+import "workflows/v1/core.proto";
+import "workflows/v1/task.proto";
+
+// HandshakeRequest is sent by the runner to a worker runtime to discover its capabilities.
+message HandshakeRequest {}
+
+// HandshakeResponse is the response to a handshake request, containing the task identifiers that the worker can execute.
+message HandshakeResponse {
+  workflows.v1.TaskIdentifiers task_identifiers = 1;
+}
+
+// ExecuteTaskResponse is the response of a worker runtime to a request to execute a task, after the task has
+// been executed.
+message ExecuteTaskResponse {
+  option (buf.validate.message).oneof = {
+    fields: [
+      "computed_task",
+      "failed_task"
+    ]
+  };
+
+  // If the task execution succeeded, this field will be set with the computed task result.
+  workflows.v1.ComputedTask computed_task = 1;
+
+  // If the task execution failed, this field will be set with details about the failure.
+  workflows.v1.TaskFailedRequest failed_task = 2;
+}
+
+// WorkerService defines the RPC interface between a runner and a a worker runtime that can execute workflow tasks.
+service WorkerService {
+  rpc Handshake(HandshakeRequest) returns (HandshakeResponse) {}
+  rpc ExecuteTask(workflows.v1.Task) returns (workflows.v1.ComputedTask) {}
+  rpc Shutdown(google.protobuf.Empty) returns (google.protobuf.Empty) {}
+}

apis/workflows/v1/worker.proto

@@ -67,7 +67,7 @@ message GetWorkflowRequest {
 message PublishWorkflowReleaseRequest {
   string workflow_slug = 1 [(buf.validate.field).string.min_len = 1];
   tilebox.v1.ID artifact_id = 2 [(buf.validate.field).required = true];
-  repeated TaskIdentifier tasks = 3 [(buf.validate.field).repeated.min_items = 1];
+  ReleaseContent content = 3 [(buf.validate.field).required = true];
 }
 
 // ListWorkflowsRequest lists all workflows.
@@ -98,11 +98,35 @@ message Workflow {
 // WorkflowRelease represents an immutable release of a workflow, which includes a set of tasks and an artifact.
 message WorkflowRelease {
   tilebox.v1.ID id = 1;
-  tilebox.v1.ID artifact_id = 2;
-  repeated TaskIdentifier tasks = 3;
+  Artifact artifact = 2;
+  ReleaseContent content = 3;
   google.protobuf.Timestamp created_at = 4;
 }
 
+// Artifact represents the artifact associated with a workflow release,
+// which is the file that contains the code and dependencies needed to execute the tasks in the release.
+message Artifact {
+  tilebox.v1.ID id = 1;
+  string digest = 2 [(buf.validate.field).string.pattern = "^[a-f0-9]{64}$"];
+}
+
+// ReleaseContent represents the content of a workflow release, which is the set of files that are included,
+// the list of task identifiers, and the command to start a worker runtime for executing the tasks in the release.
+// The fingerprint is a hash of the release content.
+message ReleaseContent {
+  string fingerprint = 1 [(buf.validate.field).string.pattern = "^[a-f0-9]{64}$"];
+  repeated TaskIdentifier tasks = 2 [(buf.validate.field).repeated.min_items = 1];
+  Path root = 3;
+  repeated string command = 4;
+}
+
+// Path represents a file or directory path in the release content. If it is a directory, it can have child paths.
+message Path {
+  string path = 1;
+  bool directory = 2;
+  repeated Path children = 3;
+}
+
 // DeployWorkflowReleaseRequest deploys a workflow release to a set of clusters, making the tasks available for
 // execution on those clusters.
 message DeployWorkflowReleaseRequest {