usage with stream.finished no longer working in node v12.16.1

[shusson]

We previously used the following pattern:

    const copyStream = client.query(
        pgCopy.from(
            `COPY MY_TABLE FROM STDIN WITH (FORMAT 'csv')`
        )
    );

    const csv: string[] = getCsvStrings();

    const input = new Readable({
        objectMode: true,
        read() {
            const item = csv.shift();

            if (!item) {
                this.push(null);
            } else {
                this.push(`${item}\n`);
            }
        }
    });

    await pipeline(input, copyStream);
    await finished(copyStream);

In node 12.16.1, await finished(copyStream); now waits indefinitely.

The pattern we used was based on the understanding that #21 and #86 would be solved by using nodes finished method. Which was working until we recently upgraded to 12.16.1. Last known working version was 12.14.0, which we have reverted to now until we figure out how to fix this.

[shusson]

It looks like node keeps changing the behviour of the streams api e.g nodejs/node#32032 nodejs/node#29699.

For now we are going with something a lot simpler and as recommended in the readme:

    await new Promise((resolve, reject) => {
        copyStream.on("error", reject);
        copyStream.on("end", resolve);
        input.on("error", reject);
        input.pipe(copyStream);
    });

[jeromew]

thanks for the report and finding a solution that works for you. This module is a bit particular because of how it needs to pipe into the postgres connection stream. It could probably be modified to have a more standard semantic but it needs work.

[jeromew]

@shusson I re-open this issue because I would be very grateful if you could test again with version 4.0.0 that was just published. It should behave correctly with the finished and pipeline API.

don't hesitate to tell me if you don't have time to do this or if you don't use this module anymore. Thank you

the writable copy-from now finishes on the standard 'finish' and not on the writable non-standard 'end'

[shusson]

@jeromew our tests pass with 4.0.0 and using pipeline 💚.

Our code looks something like this now:

    const copyStream = client.query(
        pgCopy.from(
            `COPY MY_TABLE FROM STDIN WITH (FORMAT 'csv')`
        )
    );

    const input = new Readable({
       ...
    });

    await pipeline(input, copyStream);

Thanks for the update.