Simultaneous requests to /api/flickr/most-recent-photos causes server to crash

[ryanoshea]

Can't reproduce locally, only on server.

Error [ERR_MULTIPLE_CALLBACK]: Callback called multiple times
at onwrite (_stream_writable.js:437:11)
at WriteWrap.onWriteComplete [as oncomplete] (internal/stream_base_commons.js:87:12)
at Immediate._onImmediate (/home/ryan/ryanoshea.com/backend/node_modules/handle-thing/lib/handle.js:127:11)
at processImmediate (internal/timers.js:456:21) {
code: 'ERR_MULTIPLE_CALLBACK'
}

[ryanoshea]

This looks like an incompatibility issue with spdy on Node v12.

Investigation notes:

• Error originates in a dependency of spdy. There's also a deprecation message on Node v12 with the way this package modifies headers. Possible indication that [email protected] doesn't support Node v12.
• Reverting to flickrapi doesn't prevent the issue.
• Simplifying the request down to a single promise that does res.send() in its callback doesn't prevent the issue.
• Using async/await and moving the res.send() into the body of the request handler doesn't prevent the issue.
• Removing the async/promise behavior altogether from the request handler fixes the issue.
• Downgrading to Node v10 fixes the issue.