using a database pool in a subscription resolver

[mathroc]

Hi,

I'm having trouble creating a subscription resolver that pulls data from the database. As an example let's pretend I want to get the time from the database every second. Here is what I tried:

I've got a context containing a sqlx pool:

pub struct Context {
    pub db: sqlx::PgPool,
}

impl juniper::Context for Context {
}

and I'm trying to create the resolver like this:

pub struct Subscription;

type StringStream = std::pin::Pin<Box<dyn futures::Stream<Item = Result<String, juniper::FieldError>> + Send>>;

#[juniper::graphql_subscription(context = Context)]
impl Subscription {
    async fn time<'a>(context: &Context) -> StringStream {
        let mut interval = tokio::time::interval(std::time::Duration::from_secs(1));
        let stream = async_stream::stream! {
            loop {
                interval.tick().await;

                yield sqlx::query_scalar("select 1")
                    .fetch_one(&context.db).await
                    .map_err(|err: sqlx::Error| {
                        dbg!(&err);
                        tracing::error!("{}", &err);
                        err.into()
                    })
                    .and_then(|r: i32| {
                        tracing::info!("ok");
                        executor.resolve_with_ctx(info, &r);
                        Ok( chrono::Utc::now().to_rfc3339())
                    })
            }
        };

        Box::pin(stream)
    }
}

But this wont compile:

error[E0759]: executor has lifetime 'ref_e but it needs to satisfy a 'static lifetime requirement
--> src/server/schema.rs:120:1
|
120 | #[juniper::graphql_subscription(context = Context)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| |
| this data with lifetime 'ref_e...
| ...is captured here, requiring it to live as long as 'static
|
= note: this error originates in the attribute macro juniper::graphql_subscription (in Nightly builds, run with -Z macro-backtrace for more info)

I have no problem making database queries in query and mutation endpoints but here I can't. Can someone tell me what I'm doing wrong ?

thank you

[mathroc]

I've created a very small repo reproducing the problem: https://github.com/mathroc/juniper-sqlx-subscriptions

I've also looked at #143 and try a few things but still couldn't find a solution

[mathroc]

and someone (@taufik-rama) found a solution, I needed to clone the pool outside the closure : mathroc/juniper-sqlx-subscriptions#2