Check about the changes api

[jhs]

Confirm that it works correctly

[remkoboschker]

Hi,
I just received a strange error message from the follow.js code

 "Error: Database deleted after change: 2404-g1AAAAEneJzLYWBgYMlgTmGQT0lKzi9KdUhJMtHLSs1LLUst0kvOyS9NScwr0ctLLckBKmRKZEiy____f1YGUxIDA-O3XKAYe7JRskGKsTmqGWa4zUhyAJJJ9XBjmBLBxhgYJVkmohuDxyl5LECSoQFIAU3aDzWqFGyUuYlxUnJyMtEughh1AGIUzFUzwEYZmxqkGqYZZQEAGN1ZWg\n    at Feed.on_couch_data (/home/generators/services/node_modules/cloudant/node_modules/follow/lib/feed.js:437:18)\n    at Changes.handle_confirmed_req_event (/home/generators/services/node_modules/cloudant/node_modules/follow/lib/feed.js:322:30)\n    at Changes.emit (events.js:107:17)\n    at Changes.emit_changes (/home/generators/services/node_modules/cloudant/node_modules/follow/lib/stream.js:223:12)\n    at Changes.write_continuous (/home/generators/services/node_modules/cloudant/node_modules/follow/lib/stream.js:176:8)\n    at Changes.write (/home/generators/services/node_modules/cloudant/node_modules/follow/lib/stream.js:124:17)\n    at Request.ondata (stream.js:51:26)\n    at Request.emit (events.js:107:17)\n    at IncomingMessage.<anonymous> (/home/generators/services/node_modules/request/request.js:1150:12)\n    at IncomingMessage.emit (events.js:107:17)\n    at readableAddChunk (_stream_readable.js:163:16)\n    at IncomingMessage.Readable.push (_stream_readable.js:126:10)\n    at HTTPParser.parserOnBody (_http_common.js:132:22)\n    at TLSSocket.socketOnData (_http_client.js:317:20)\n    at TLSSocket.emit (events.js:107:17)\n    at readableAddChunk (_stream_readable.js:163:16)",

Luckily the database was not deleted 😃

[jhs]

Ha ha, sorry, that is very likely my own code that output that. "Printer on fire!"

I think the code detects for 404 or other errors and assumes the database is deleted. That is one way to trigger that code path, but apparently not the only way.

We are working to close this by this coming Tuesday at the latest.

[jhs]

@remkoboschker Have you still got this bug in the new 1.1 release? I think you may still have it. If so, we can work more fixes into the Follow and Nano code, which are dependencies of the Cloudant package.

[remkoboschker]

@jhs I'll update and keep you informed. I'm not sure how I can reproduce the bug.

[jhs]

Hi, @remkoboschker. I will close this ticket for now, since all the tests I can think of are passing. However, I definitely think there is still brittleness in the changes code. However I'll open a fresh ticket about that as I encounter it. Thanks!

[remkoboschker]

@jhs thank you. I'll let you know when I observe any strange behaviour.

[remkoboschker]

Using version 1.2.0

{
  "message": "Database deleted after change: 3406-g1AAAAEneJzLYWBgYMlgTmGQT0lKzi9KdUhJstTLSs1LLUst0kvOyS9NScwr0ctLLckBKmRKZEiy____f1YGUxKQ9zkXKMZuapZsmJaYgmqGKW4zkhyAZFI93BjmALAxqYaWKUkpBkQ7JY8FSDI0ACmgSfuhRlWBjTJINEg1SUwl2kUQow5AjIK5aiLYqEQzA3Mzg9QsAHr6Wd8",
  "stack": "Error: Database deleted after change: 3406-g1AAAAEneJzLYWBgYMlgTmGQT0lKzi9KdUhJstTLSs1LLUst0kvOyS9NScwr0ctLLckBKmRKZEiy____f1YGUxKQ9zkXKMZuapZsmJaYgmqGKW4zkhyAZFI93BjmALAxqYaWKUkpBkQ7JY8FSDI0ACmgSfuhRlWBjTJINEg1SUwl2kUQow5AjIK5aiLYqEQzA3Mzg9QsAHr6Wd8\n    at Feed.on_couch_data (/home/generators/services/node_modules/cloudant/node_modules/nano/node_modules/follow/lib/feed.js:440:18)\n    at Changes.handle_confirmed_req_event (/home/generators/services/node_modules/cloudant/node_modules/nano/node_modules/follow/lib/feed.js:325:30)\n    at Changes.emit (events.js:107:17)\n    at Changes.emit_changes (/home/generators/services/node_modules/cloudant/node_modules/nano/node_modules/follow/lib/stream.js:223:12)\n    at Changes.write_continuous (/home/generators/services/node_modules/cloudant/node_modules/nano/node_modules/follow/lib/stream.js:176:8)\n    at Changes.write (/home/generators/services/node_modules/cloudant/node_modules/nano/node_modules/follow/lib/stream.js:124:17)\n    at Request.ondata (stream.js:51:26)\n    at Request.emit (events.js:107:17)\n    at IncomingMessage.<anonymous> (/home/generators/services/node_modules/cloudant/node_modules/nano/node_modules/follow/node_modules/request/request.js:1164:12)\n    at IncomingMessage.emit (events.js:107:17)\n    at readableAddChunk (_stream_readable.js:163:16)\n    at IncomingMessage.Readable.push (_stream_readable.js:126:10)\n    at HTTPParser.parserOnBody (_http_common.js:132:22)\n    at TLSSocket.socketOnData (_http_client.js:317:20)\n    at TLSSocket.emit (events.js:107:17)\n    at readableAddChunk (_stream_readable.js:163:16)",
  "deleted": true,
  "last_seq": "3406-g1AAAAEneJzLYWBgYMlgTmGQT0lKzi9KdUhJstTLSs1LLUst0kvOyS9NScwr0ctLLckBKmRKZEiy____f1YGUxKQ9zkXKMZuapZsmJaYgmqGKW4zkhyAZFI93BjmALAxqYaWKUkpBkQ7JY8FSDI0ACmgSfuhRlWBjTJINEg1SUwl2kUQow5AjIK5aiLYqEQzA3Mzg9QsAHr6Wd8",
  "time": "2015-08-19T14:10:47.105Z",
  "level": "err"
} 

I happy to report the database is still there. Also there were no changes at all.

[remkoboschker]

again at "2015-09-09T16:41:47.691Z"; does this mean there was a service interuption at cloudant?

[nicolelovecoding]

Just received the same error: "Error: Database deleted after change:...."

[csaroff]

It seems this issue is percolating up from the follow api. I've put in an issue there, but I'm not sure if this repository is still being maintained. In the meantime, anyone who is having this issue can look at the pouchdb changes api which also appears to extend EventListener.