triggers unhandled promise rejection that we cannot prevent

Environment details

• OS: linux
• Node.js version: 10
• npm version: 7
• @google-cloud/spanner version: 5.5.0

Steps to reproduce

Create this js file and run it (no need for a spanner instance to be setup).

This sample will try to connect to spanner with an unexisting instance name just because it’s simpler to simulate the error this way, but it seems to occur with any error… It will result in an error when doing the insert. The error will be caught in the catch statement, but it will also throw an unhandled promise rejection. The promise rejection that cannot be caught without unhandledRejection event is not a desired behavior for a 3rd party library.

const {Spanner} = require("@google-cloud/spanner");

run();

async function run() {
    try {
        const spanner = new Spanner({
            projectId: 'somebrokenprojectid',
        });

        const instance = spanner.instance("somebrokeninstance");
        const database = instance.database("somedb");

        const table =  database.table("sometable");

        console.log('insert data');

        await table.insert([{somekey: "somevalue"}]);
    } catch (e) {
        console.error('caught exception', e.message)
    }
}

Thanks

[skuruppu]

@gsouf I think it would mean that the first batch of sessions are created when executing the first request so there will be a small increase in latency for the first request. But sessions are created in batches so for subsequent requests, it shouldn’t be an issue.

In any case, #1332 will handle the specific case you came across in your first comment so you won’t need to use {min: 0}.

[skuruppu]

@AVaksman would you please be able to take a look?