Wrapper Snippet

gistfile1.txt

// Here’s a snippet that likely provides a clearer explanation of why my organization chose to use a wrapper.
// The primary motivation was to unify instrumentation in alignment with both industry standards and organizational practices.

pub struct MyAsyncPgConnection {
    conn: AsyncPgConnection,
    span_provider: PgQuerySpan,
}

impl MyAsyncPgConnection {
    /// Build a transaction, specifying additional details such as isolation level
    pub fn build_transaction(&mut self) -> TransactionBuilder<Self> {
        // This is what I would like to be able to do
        TransactionBuilder::new(self)
    }
}

impl AsyncConnection for MyAsyncPgConnection {
    async fn establish(database_url: &str) -> ConnectionResult<Self> {
        async {
            // create the connection with or without TLS depending on env
            let mut conn = ...

            let namespace = diesel::select(current_database())
            .get_result(&mut conn)
            .await
            .map_err(ConnectionError::CouldntSetupConfiguration)?;

            Ok(PgConnection {
                conn,
                span_provider: PgQuerySpan::new(namespace),
            })
        }
        .inspect_err(|e| {
            // record error with the necessary semantic fields
            // https://github.com/open-telemetry/semantic-conventions/blob/main/docs/exceptions/exceptions-spans.md
        })
        .instrument(PgEstablishSpan.span())
        .await
    }

    fn load<'conn, 'query, T>(&'conn mut self, source: T) -> Self::LoadFuture<'conn, 'query>
    where
        T: AsQuery + 'query,
        T::Query: QueryFragment<Self::Backend> + QueryId + 'query,
    {
        self.conn.load(source).instrument(self.span_provider.span())
    }

    ...
}

pub struct PgQuerySpan {
    namespace: String,
}

impl PgQuerySpan {
    pub fn new(namespace: String) -> Self {
        Self { namespace }
    }
}

impl SpanProvider for PgQuerySpan {
    fn span(&self) -> Span {
        info_span!(
            "query",
            // set up a handful of standard fields
        )
    }
}