Getting "Error: EOF: end of file, read" on Windows

[ot-jim-elphick]

description of the bug:

returns JSII error on empty stack. May be related to #5187.

stack trace references SyncStdio.readLine (myfolder\jsii_embedded\jsii\jsii-runtime.js:13278:33)
Comment in code at 'throw e':

// HACK: node may set O_NONBLOCK on it's STDIN depending on what kind of input it is made
// of (see https://github.com/nodejs/help/issues/2663).
. . .
// "tracked" at https://github.com/aws/aws-cdk/issues/5187

Reproduction Steps

(using powershell) This follows example from https://docs.aws.amazon.com/cdk/latest/guide/ecs_example.html

mkdir myfolder
cd myfolder
cdk init --language python
.env\Scripts\activate.ps1
python -m pip install -r requirements.txt
cdk synth

What did you expect to happen?

return an empty stack with no error

What actually happened?

(.env) p$[myfolder]> cdk synth                                                                                                                      D:\d:\myfolder\.env\lib\site-packages\jsii\_embedded\jsii\jsii-runtime.js:13295
                    throw e;
                    ^

Error: EOF: end of file, read
    at Object.readSync (fs.js:592:3)
    at SyncStdio.readLine (D:\d:\myfolder\.env\lib\site-packages\jsii\_embedded\jsii\jsii-runtime.js:13278:33)
    at InputOutput.read (D:\d:\myfolder\.env\lib\site-packages\jsii\_embedded\jsii\jsii-runtime.js:13203:34)
    at KernelHost.run (D:\d:\myfolder\.env\lib\site-packages\jsii\_embedded\jsii\jsii-runtime.js:13021:32)
    at Immediate.<anonymous> (D:\d:\myfolder\.env\lib\site-packages\jsii\_embedded\jsii\jsii-runtime.js:13029:37)
    at processImmediate (internal/timers.js:461:21) {
  errno: -4095,
  syscall: 'read',
  code: 'EOF'
}
Resources:
  CDKMetadata:
    Type: AWS::CDK::Metadata
    Properties:
      Modules: aws-cdk=1.69.0,@aws-cdk/cloud-assembly-schema=1.69.0,@aws-cdk/core=1.69.0,@aws-cdk/cx-api=1.69.0,@aws-cdk/region-info=1.69.0,jsii-runtime=Python/3.7.4
    Metadata:
      aws:cdk:path: myfolder/CDKMetadata/Default
    Condition: CDKMetadataAvailable

Environment

• CLI Version : aws-cli/2.0.61 Python/3.7.7 Windows/10 exe/AMD64
• Framework Version: 1.69.0 (build 2b474b9)
• Node.js Version: v14.15.0
• OS : Windows 10
• Language (Version): python 3.7.4

Other

Error is persistent and easily reproduced on my machine.
I re-installed/upgraded aws cli to 2.0.61
I re-installed node.js
I re-installed cdk
Note: As noted in the section above, this 'hello world' level error still creates a stack. However, when more code is added, more jsii errors occur and the stack fails. Also, code that errors on my machine runs normally on other machines.

[RomainMuller]

I am unable to reproduce this problem on macOS/UNIX. Have to prepare a windows environment to attempt reproduction there; which might take a little while.

[RomainMuller]

Good news - I was able to reproduce it now (on Windows)! I'll try to figure out what's happening here...

[RomainMuller]

Alright - so the EOF error is thrown by fs.readSync on Windows when EOF. This does not appear to happen on *nixes and I'm also unable to directly reproduce this behavior (when I try to, the fs.readSync call properly returns 0 when EOF is reached, as documented).

This isn't quite the first oddity we have faced that mostly affects Windows users (as you've noted the hack we already have in place for EAGAIN)... I'm going to try a little harder to identify a reproduction and hopefully be able to file a bug report to node...

Interestingly, this error happens as the app has correctly finished (the Python process then closes the node process' STDIN to signal it's done and the node process should clean up after itself and exit - and this is what triggers the crash). This actually you'd be able to "work around" this by running your app.py and then running cdk with -a cdk.out until we have found a way to conclusively fix this problem.

If we're not finding a better solution fast enough, we'll have to actually identify this EOF error and actually handle it was if fs.readSync had returned 0....

[RomainMuller]

Alright I have been able to come up with a simple repro, which actually demonstrates the reason I could not "easily" reproduce previously is because of the difference in nature of the process.stdin when node is started directly as opposed to when Python creates a subprocess with piped in- and output.

[RomainMuller]

Filed a bug to NodeJS (nodejs/node#35997).

[ot-jim-elphick]

Merci! Thank you for your help!

This tells me to focus on node.js. I will try using some previous version of node.js as a remedy. If that works, I will post the nodejs version here.