Cmd Invocation

Need to cater for:

  1. CLI usage: Invocation returns the result.
  2. Web usage: Invocation returns an ID.
  3. Any usage: For a given profile, two CmdExecutions cannot run at the same time, even for different flows.
  4. Web usage: For a given profile, re-invocation returns existing in-progress CmdExecution ID. This can be deferred if two browser tabs for the same workspace + profile combination both disable the deploy button when a CmdExecution is initiated.

Option A1: exec delegates to request_exec

For the CLI usage, to reduce code duplication *Cmds can provide function that return the Result<CmdOutcome, ..>, where internally it calls the method that returns an execution ID, but immediately waits for that execution's completion.

fn main() {
pub async fn exec<'ctx>(
    cmd_ctx: &mut CmdCtx<SingleProfileSingleFlow<'_, CmdCtxTypesT>>,
) -> Result<CmdOutcome<_, CmdCtxTypesT::AppError>, CmdCtxTypesT::AppError>
    CmdCtxTypesT: 'ctx,
    let execution_id = Self::request_exec(cmd_ctx);


Option A2: request_exec delegates to exec

pub async fn request_exec<'ctx>(
    cmd_ctx: &mut CmdCtx<SingleProfileSingleFlow<'_, CmdCtxTypesT>>,
) -> ExecutionId
    CmdCtxTypesT: 'ctx,
    if let Some(execution_id) = executions.get((workspace, profile)) {
        return execution_id;

    let execution_id = server.generate_execution_id(workspace, profile).await;
    let cmd_execution = Self::exec(cmd_ctx);
    // or send(..) the execution request to a queue, and the queue receiver calls the `exec`.

    executions.put(execution_id, cmd_execution).await


Web Interface

Web Server:

  • Needs to hold a collection of all executions.

  • Needs to hold mapping from Execution ID to CmdExecution, and/or parts of the CmdExecution.

    Storing parts separately can with access and extensibility:

    • Sometimes we don't want to borrow the full CmdExecution, only part of it.
    • Adding new things gets stored in a different server context state, so components that are not concerned with the new state don't need to access it.

    Need to make sure all context is added in the same place, otherwise it is difficult to track "what makes up a CmdExecution".

1. Web Server CmdExecutions Tracking

  • CmdExecutions is the collection of in-progress executions, not just their serializable info.

    Possibly a LinkedHashMap<ExecutionId, Box<dyn CmdExecutionRt>>, where CmdExecutionRt is a trait over the concrete CmdExecutions which are type parameterized.

  • CmdExecutionsInfo is a serializable collection of both in-progress and historical execution infos.

    Possibly a LinkedHashMap<ExecutionId, CmdExecutionInfo>.

// Web Server set up needs to track everything
// or, link to a database that tracks everything
let cmd_executions = CmdExecutions::default();
let router = Router::new()
    // ..
        move || {
            // ..
        move || view! {  <Home /> },
    // ..

2. Web Component CmdExecutionInfos Access For Display

CmdExecutionInfos is the serializable type used to represent CmdExecutions for display:

/// Returns the list of `CmdExecutions` that have run / are in-progress on the server.
#[leptos::server(endpoint = "/cmd_execution_infos")]
pub async fn cmd_execution_infos(
) -> Result<CmdExecutionInfos, ServerFnError<NoCustomError>> {
    let cmd_execution_infos = leptos::use_context::<CmdExecutionInfos>()
        .ok_or_else(|| {
                "`CmdExecutionInfos` was not set.".to_string()


pub fn CmdExecutionsList() -> impl IntoView {
    let cmd_execution_infos_resource = leptos::create_resource(
        || (),
        move |()| async move { cmd_execution_infos().await.unwrap() },
    let cmd_execution_infos = move || {
            .expect("Expected `cmd_execution_infos` to always be generated successfully.")

    view! {
        <Transition fallback=move || view! { <p>"Loading..."</p> }>
            <For each=cmd_execution_infos /* display the info */ />

3. Web Component CmdExecutions Access For *Cmd Invocation

Given a workspace, profile, flow_id, a *Cmd and *Cmd parameters, a user should be able to send a CmdExecutionRequest. Some of these parameters should be able to be defaulted, e.g. for a local automation server which is run from the workspace directory.

Should create_action or create_server_action be used?

Answer From @Lazer (discord)

You can provide params to server actions via hidden inputs if necessary.

#[server(endpoint = "check_code")]
pub async fn check_code(s: Uuid, c: Code) -> Result<UserMetadata, ServerFnError> {

let check_action = create_server_action::<CheckCode>();
<ActionForm action=check_action class="mx-auto px-6 py-4 rounded-xl bg-white max-w-[400]">
    <input type="hidden" id="s" name="s" value=s />
    <div class="mb-4">
        <label for="c" class="block text-md text-gray-700">
            Verification Code
            class="various tailwind"
            id="c" name="c" prop:value=c required type="number" placeholder="6 digit code"
            on:input=move |ev| c.set(event_target_value(&ev))/>
    <ErrorDisplay res=check_action />
    <div class="mb-6">
        <p class="text-sm my-1 text-grey-600" hidden=move || email().is_none()>
            Sent code to {move || email()}
        <a class="text-sm my-1 text-grey-600 hover:underline" href="loginhelp">
            "Didn't get an email?"
    <button type="submit" disabled=check_action.pending()
        class="various tailwind">


#[derive(Clone, Debug, PartialEq, Eq, Deserialize, Serialize)]
pub struct EnsureCmdArgs {
    workspace: Workspace,
    profile: Profile,
    flow_id: FlowId,

pub struct CmdExecutionQueues(HashMap<(Workspace, Profile), Sender<CmdExecutionRequest>>);

#[leptos::server(endpoint = "/ensure_cmd")]
pub async fn ensure_cmd(
    ensure_cmd_args: EnsureCmdArgs,
) -> Result<ExecutionId, ServerFnError<NoCustomError>> {
    let cmd_execution_queues = leptos::use_context::<CmdExecutionQueues>()
        .ok_or_else(|| {
                "`Sender<CmdExecutionRequest>` was not set.".to_string()
    let cmd_execution_infos = leptos::use_context::<CmdExecutionInfos>()
        .ok_or_else(|| {
                "`Sender<CmdExecutionInfos>` was not set.".to_string()

    let execution_id = cmd_execution_queues.get(&(workspace, profile))
        .map(|cmd_execution_req_tx| {
            let execution_id = ExecutionId::new_rand();
            let cmd_execution_req = CmdExecutionReq {

            let cmd_execution_info = CmdExecutionInfo::new(execution_id, ensure_cmd_args);
            cmd_execution_infos.insert(execution_id, cmd_execution_info);


        .ok_or_else(|| {
                format!("No `CmdExecutionQueue` for {workspace} {profile}.")


pub fn EnsureButton() -> impl IntoView {
    let ensure_cmd = leptos::create_action(
        |workspace: Workspace, profile: Profile, flow_id: FlowId| {
            let execution_id = execution_id.clone();
            async move { ensure_cmd(EnsureCmdParams { workspace, profile, flow_id }).await }
    let submitted = ensure_cmd.input(); // RwSignal<Option<String>>
    let pending = ensure_cmd.pending(); // ReadSignal<bool>
    let todo_id = ensure_cmd.value(); // RwSignal<Option<Uuid>>

    view! {
            on:submit=move |ev| {
                ev.prevent_default(); // don't reload the page.
            // Execution ID
            <button type="submit">"Deploy"</button>
        // use our loading state
        <p>{move || pending().then("Loading...")}</p>