[BUG] Download as CSV always fails: `There was an error generating this report.`

[bjenkins-partstech]

What is the bug?

This command to download a report as a CSV fails after about a minute despite the timeout being set to 5 minutes. Subsequent attempts from the UI fail immediately with Download error: There was an error generating this report.

$ npx -y @opensearch-project/reporting-cli --url "https://opensearch.vpn.address.com/_dashboards/goto/4b051e8780007aff9e295ca8dbce8c79?security_tenant=global" --auth basic --credentials "username:password" --format csv --timeout 300000
✔ Fetched argument values
⠋ Connecting to url https://opensearch.vpn.address.com/_dashboards/goto/4b051e8780007aff9e295ca8dbce8c79?security_tenant=global(node:2624) NOTE: The AWS SDK for JavaScript (v2) is in maintenance mode.
 SDK releases are limited to address critical bug fixes and security issues only.

Please migrate your code to use AWS SDK for JavaScript (v3).
For more information, check the blog post at https://a.co/cUPnyil
ℹ Credentials are verified
ℹ Connected to url https://opensearch.vpn.address.com/_dashboards/goto/4b051e8780007aff9e295ca8dbce8c79?security_tenant=global
✖ Downloading report failed. TypeError: Cannot read properties of undefined (reading 'toString')

How can one reproduce the bug?

It's a self-hosted instance behind a VPN. What can I do to debug this?

What is the expected behavior?

It downloads the report as a CSV.

What is your host/environment?

OpenSearch v2.5.0

Do you have any screenshots?

Do you have any additional context?

I have another command with a different search that works just fine:

$ npx -y @opensearch-project/reporting-cli --url "https://opensearch.vpn.address.com/_dashboards/goto/7f6a07733e45b3c7b784900d9849f712?security_tenant=global" --auth basic --credentials "username:password" --format csv --timeout 300000
✔ Fetched argument values
⠋ Connecting to url https://opensearch.vpn.address.com/_dashboards/goto/7f6a07733e45b3c7b784900d9849f712?security_tenant=global(node:24436) NOTE: The AWS SDK for JavaScript (v2) is in maintenance mode.
 SDK releases are limited to address critical bug fixes and security issues only.

Please migrate your code to use AWS SDK for JavaScript (v3).
For more information, check the blog post at https://a.co/cUPnyil
(Use `node --trace-warnings ...` to show where the warning was created)
ℹ Credentials are verified
ℹ Connected to url https://opensearch.vpn.address.com/_dashboards/goto/7f6a07733e45b3c7b784900d9849f712?security_tenant=global
✔ The report is downloaded

[bjenkins-partstech]

Now we're seeing:

Downloading report failed. ProtocolError: Protocol error (Network.getResponseBody): Request content was evicted from inspector cache

[andrross]

Catch All Triage - 1

[bjenkins-partstech]

Just wondering if there is anything I can do in the meantime (logs I could pull/toggle debug or verbose modes) while this is pending investigation?

[sp01041998]

I was facing the same issue when trying to download a report as CSV using the OpenSearch Reporting CLI. The command would hang for about a minute and then fail, even though I had set the timeout to 5 minutes (--timeout 300000).
"Download error: There was an error generating this report."

The issue happens because the CLI attempts to click the generateCSV button before the page is fully ready, or when the button is disabled due to an unsaved or invalid search state. This leads to a failed report generation and, crucially, caches a failed state on the backend, which then causes subsequent report attempts (even from the UI) to fail immediately.

I patched the CLI to include proper retries and checks to avoid clicking the generateCSV button too early. Here's the working solution I added:
Working Fix :
if (format === FORMAT.CSV) {
while (retries < MAX_RETRIES) {
let elementHandle = null;
try {
elementHandle = await page.waitForSelector('button[id="downloadReport"]', {
visible: true,
timeout: 15000,
});

  if (elementHandle) {
    break;
  }
} catch (e) {
  // Ignored, will retry
}

retries++;
if (retries < MAX_RETRIES) {
  await page.reload({ waitUntil: 'domcontentloaded' });
  await new Promise(resolve => setTimeout(resolve, 2000));
}

}

if (retries === MAX_RETRIES) {
spinner.fail('❌ downloadReport button not found after max retries.');
process.exit(1);
}

await page.click('button[id="downloadReport"]');
await new Promise(resolve => setTimeout(resolve, 1000));

const is_enabled = await page.evaluate(() => {
return document.querySelector('#generateCSV[disabled]') === null;
});

if (is_enabled) {
const catcher = page.waitForResponse(r =>
r.request().url().includes('/api/reporting/generateReport')
);
await page.click('button[id="generateCSV"]');
const response = await catcher;
const payload = await response.json();
buffer = payload.data;
} else {
spinner.fail('❌ generateCSV button is disabled. Please save search and retry.');
process.exit(1);
}
}