OfWatchdogMissingContentLength
commented
3 years ago I've done some more digging and debugging, and it seems the issue is that although a Content-Length is known, of-watchdog instead sends an HTTP request with Transfer-Encoding: chunked, which is not yet supported by my Nim server.
I claim this is still a bug/unexpected behaviour, but it wasn't obvious to me if this is something done by of-watchdog or the go standard library.
See logs:
2021/01/06 05:00:23 map[Accept:[text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8] Accept-Encoding:[gzip, deflate] Accept-Language:[en-CA,en-US;q=0.7,en;q=0.3] Cache-Control:[no-cache] Connection:[keep-alive] Content-Length:[11] Dnt:[1] Origin:[http://159.89.118.201:9999] Pragma:[no-cache] Upgrade-Insecure-Requests:[1] User-Agent:[Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:84.0) Gecko/20100101 Firefox/84.0]]
POST / HTTP/1.1
Host: 159.89.118.201:9999
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Encoding: gzip, deflate
Accept-Language: en-CA,en-US;q=0.7,en;q=0.3
Cache-Control: no-cache
Connection: keep-alive
Content-Length: 11
Dnt: 1
Origin: http://159.89.118.201:9999
Pragma: no-cache
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:84.0) Gecko/20100101 Firefox/84.0
hello=world
2021/01/06 05:00:23 stderr: Got raw line: Host: 159.89.118.201:9999
2021/01/06 05:00:23 stderr: Got raw line: User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:84.0) Gecko/20100101 Firefox/84.0
2021/01/06 05:00:23 stderr: Got raw line: Transfer-Encoding: chunked
2021/01/06 05:00:23 stderr: Got raw line: Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
2021/01/06 05:00:23 stderr: Got raw line: Accept-Encoding: gzip, deflate
2021/01/06 05:00:23 stderr: Got raw line: Accept-Language: en-CA,en-US;q=0.7,en;q=0.3
2021/01/06 05:00:23 stderr: Got raw line: Cache-Control: no-cache
2021/01/06 05:00:23 stderr: Got raw line: Connection: keep-alive
2021/01/06 05:00:23 stderr: Got raw line: Dnt: 1
2021/01/06 05:00:23 stderr: Got raw line: Origin: http://159.89.118.201:9999
2021/01/06 05:00:23 stderr: Got raw line: Pragma: no-cache
2021/01/06 05:00:23 stderr: Got raw line: Upgrade-Insecure-Requests: 1
alexellis
derek[bot]
I'm trying to set up a Nim HTTP function using of-watchdog. I've managed to configure of-watchdog in HTTP mode where GET and POST (with no data) work as expected. However, upon trying to send a POST with data, I get a
Content-Length required.response from Nim.Expected Behaviour
I would expect the setup to work for POST with data, ie. the entire set of headers should be forwarded, including Content-Length. I've tried using of-watchdog versions 0.7.2, 0.7.7, and 0.8.1 and none of them worked as expected.
I would like to see the Content-Length header in my final HTTP server.
Current Behaviour
Neither the headers being passed to the upstream url nor the headers made available in cgi_headers include the content length.
Possible Solution
I believe that Go treats the Content-Length header specially, and for some reason it doesn't seem to get passed on.
A possible solution would be to manually include the Content-Length header, and set it to Request.ContentLength (per https://golang.org/pkg/net/http/#Request).
Steps to Reproduce (for bugs)
A live example is available at http://159.89.118.201:8080/function/nim-sudoku-faas - start at step 5 below.
To reproduce, the full source code can be used with the following steps:
git clone https://gitlab.com/vabresto/nim-sudoku-faas/-/tree/master nim-sudoku-faascd nim-sudoku-faasvim stack.ymland change the image fromregistry.gitlab.com/vabresto/nim-sudoku-faasto an appropriate image name you can push tofaas-cli deployContent-Length required.as the reply, instead of the completed board.If you run just the nim code (ex.
cd nim-sudoku-faas/nim-sudoku && nimble runthen connect to127.0.0.1:8888), clicking the "Solve" button will correctly return a solved sudoku board.Note that the "Reset" button works because that is just refreshing the page.
This is the line in the Nim server where the failure occurs: https://github.com/nim-lang/Nim/blob/devel/lib/pure/asynchttpserver.nim#L250 Note that I've included a version of this file with some debug print statements in my source code, called
instr_asynchttpserver.nim, which is how the logs below were produced.I believe this might be a good starting point for debugging the Go code: https://github.com/openfaas/of-watchdog/blob/master/executor/http_runner.go#L100
Current debug output:
I think the bad request at the end is due to trying to fetch a favicon, but I'm not sure. I'd like to get rid of that error if possible.
Context
I'm trying to build a proof of concept Nim function-as-a-service. I don't want to use the classic watchdog because having control over incoming and outgoing HTTP headers is valuable, and it allows for testing the function outside of the container for dev purposes more easily.
I can't work around this (ex. by changing the stdlib Nim HTTP server implementation to fetch the values from the environment) because the env isn't correctly populated either.
Your Environment
docker version(e.g. Docker 17.0.05 ):I'm using
faasdwith--lang=dockerfileUbuntu 20.04
Code: https://gitlab.com/vabresto/nim-sudoku-faas/-/tree/master Live: http://159.89.118.201:8080/function/nim-sudoku-faas
Note there is also a Python endpoint I tried using available at http://159.89.118.201:8080/function/pls that does manage to include the Content-Length, which uses the
python3-httptemplate available from the store, withhandler.pyset toIncludes the full function setup, running
faas-cli upshould set everything up (may need to change image prefix).