git clone ssh failing

mstonespeedy

Hey, everyone. I'm new to Pythonista, and anxious to see what it can do!

I'm just about ready to grab some scripts from our company git repository to play with. I am successfully connecting to our company Git server through ssh. However, about 6 seconds after I try a git clone ssh://..., I get the error:

stash: <class 'dulwich.errors.HangupException'>: The remote server unexpectedly closed the connection.

The server logs show a successful session open, but they don't show a session close message until 3 minutes later, so it seems to be an issue with stash/ssh/dulwich.

StaSh v0.6.15
dulwich 0.12.2

Any ideas?

JonB

Hi, how did you create your keys? The gh command has a command to create a ssh key and link it to github. while github can support 4096 bit keys, I think I had trouble with paramiko and 4096 bit.

Someone else recently had the hangup issue. @simcitywok i think, and i think he solved it by reinstalling dulwich. Also, make sure you have a solid connection -- this means the server dropped the connection unexpectedly. You might try running the command multiple times in a row, to see if you can get a valid connection.

Second, try deleting dulwich from site packages, then force quit pythonista. Then try running git again, which will download dulwich again.

Note we use a special custom version of dulwich, so if you installed yours yourself, that is a problem. Let the git command install it.

ssh on stash is pretty slow, so the initial clone might be problematic, since it has to download the entire history. You might try using https for the initial clone, then ssh subsequently.

mstonespeedy

Thanks for your help, @JonB.

I got this far following your very helpful post at https://forum.omz-software.com/topic/1848/working-copy-integration-sidebar/42. So, I used the following to generate the keys:

ssh-keygen -t rsa -b 2048

And I saw the hangup issue @SimCityWok was having, so I've done multiple retries with no success. Each time I try, it fails within 6 seconds. I've tried https, but it gives the same error.

I've now deleted dulwich and allowed git to reinstall it, but there's no difference in behavior.

I'm successfully connecting to the server via ssh, so that part of it is working properly. Wouldn't the problem be in dulwich, then?

JonB

Are you able to run ssh directly and connect / comm with the server? (if you have an account with terminal access). That would distinguish between a dulwich and paramiko problem.

Can you verify the paramiko version you are using? Likely you need 1.16.

Are you able to try https, at least for the initial clone?

Another check, trying ssh with a small repo:

[~/Documents]$ mkdir blah
[~/Documents]$ cd blah
[blah]$ git init .
[blah]$ git commit blah blah blah 
d8192599eff9eab370a6c2052b74a4d03419a59c
[blah]$ git branch
* masterd819259
[blah]$ git branch blah 
[blah]$ git checkout blah
[blah]$ git branch -D master
deletemaster['master']False
removing master (was d8192599eff9eab370a6c2052b74a4d03419a59c)
[blah]$ git remote origin ssh://yourserver
[blah]$ git push

(if you have the ability to create a new repo, that would be simpler and safer, the above is to try to avoid nuking master, by creating a new, empty branch, then pushing that... though if you can create a new repo, try cloning a repo with only 1 commit.)

If that works, then the issue is maybe just the big initial clone. try git fetch, or use https for initial clone.

if maybe the large clone is the issue: try:
git init somefolder
cd somefolder
git branch -c newbranch
echo test>test.txt
git add test.txt

git remote origin ssh://yourserver

mstonespeedy

Thanks again for your help, @JonB.

Yes, I'm able to connect to the server via ssh and run commands there. That's why I'm assuming it's a dulwich problem.

I have verified that I have paramiko 1.16.0.

No, https doesn't work either, even just for the initial clone.

Executing your sample commands gives me the same error as before ("The remote server unexpectedly closed the connection.").

Is there a way to turn on debugging messages in dulwich?

JonB

Unfortunately, this type of thing is usually prett opaque in dulwich, since the server closes the connection, and dulwich does not know why.

are you able to clone github repo's?

You could try installing the latest dulwich, then use dulwich.porcelain, (not with stash) along with pdb to try to trace through what is happening, but if you search for the specific error in dulwich.client, I think you will find there is nothing that dulwich knows about.

mstonespeedy

Thanks again for your help, @JonB. It sounds like you're confident that the problem is on the server rather than in dulwich. I'll see if I can get any other information from our server administrator.

JonB

well, no, i am not at all confident!

It would be worth installing the latest dulwich, and trying porcelain.clone().
Do the same from a pc, to isolate the problem to a dulwich one, in which case you should open an issue at the dulwich page. You might need to note what server software you are using.

mstonespeedy

I haven't tried github, but I can clone repos from our server using other clients over ssh. I'm pretty certain it's a problem with dulwich, since the server session close message is logged well after dulwich gives up. I'll log an issue on the dulwich page. Thanks again for your help!

JonB

it is a dulwich problem, but what we have to discover is whether it is a pythonista stash dulwich problem, or dulwich in general, or a problem with your specific setup.

If you can't clone from github, then we know the problem is in your setup.
If you can clone from a desktop to your server using dulwich, the problem is in the ios +dulwich combo. If you can clone using dulwich without stash, the problem is with stash git.

mstonespeedy

Makes sense, thanks. I'll do some more digging when I get a chance.

mstonespeedy

Quick update. I'm not sure when I'll have time to debug dulwich, but I wanted to at least log where I got to.

I can clone from github.

I can also clone from our company Git repository using the Working Copy iOS app with its ssh support.

mstonespeedy

I just realized that I have been working with Pythonista 2, rather than Pythonista 3. I wondered if that made a difference. So I deleted Pythonista 2 and installed Pythonista 3. The first time I did a git clone ssh, it installed dulwich for me. But as I was testing straight ssh connections, somehow dulwich was deleted. Subsequent tries of git clone ssh won't reinstall dulwich. How do I install the appropriate version of dulwich now?

dgelessus

@mstonespeedy As far as I know stash git automatically installs any missing libraries that it needs, it's not a one-time thing. Make sure that there is no dulwich in any of the three site-packages folders, then restart Pythonista to get a clean Python environment (with no cached modules), then stash should install dulwich again the next time you use git.

mstonespeedy

That's what I thought, too. But dulwich is nowhere to be found, in any of the 3 site-packages folders. I've restarted Pythonista and tried git clone ssh multiple times. I get the message:

stash: <class 'paramiko.ssh_exception.SSHException'>: No authentication methods available

JonB

stash by default installs the git dependencies into stash/lib.

Make sure you install your ssh keys into ~/.ssh. This might be a d fferent folder than in py2, so you may want to copy them cp ~/../.ssh ~/.ssh. I should have mentioned that while ssh looks in two places, git only looks in ~/.ssh.

JonB

Also, I will point out that stash actually uses the python2 interpreter within pythonista 3. Also, in recent beta versions, subprocess got mucked up, which breaks the exceptions that get caught in dulwich. The fix is

import subprocess
if not hasattr(subprocess,'call'):
	def Popen(*args,**kwargs):
		pass
	def call(*args,**kwargs):
		return 0
	subprocess.Popen=Popen
	subprocess.call=call

If you try using dulwich directly, just move the dulwich folder from stash/lib to site-packages, and you can then try using dulwich.porcelain.clone.That should work in either the py2 or py3 interpreter. You may need

dulwich.client.get_ssh_vendor = dulwich.client.ParamikoSSHVendor

mstonespeedy

Thanks for the additional detail, @JonB.

I did indeed need that second .ssh folder to get back where I was with Pythonista 2. And I did find the dulwich folder in stash/lib. Oh, and git.py has the ParamikoSSHVendor line. However, I'm back to the same error as before ("The remote server unexpectedly closed the connection.").

I'll try to look into the subprocess issue later today. Is Jelmer aware of it?

JonB

The subprocess issue is a pythonista issue, not dulwich. Because IOS does not let you spawn a subprocess, the newer betas commented out those parts of the standard lib (earlier versions still had all the named defined, but raised errors). dulwich imports Popen and call, but the normal workflow does not need them. (used for executing hooks, or certain type of local repositories)

BTW, in stash, you can use stashconf py_pdb 1 to enable pdb when an error is encountered. Or stashconf py_traceback 1 to print a full traceback.

You might try importing dulwich and using porcelain. There are some ways to try to request just a single branch for instance, or, say a single commit, just to see if the connection works.

mstonespeedy

Thanks for the tips, @JonB.

Has the subprocess issue been reported? I don't have a beta version of anything I'm using, as far as I know. Which files should I look for?

I tried using dulwich.porcelain.clone('ssh://user@git.myCompany.com/MyRepository.git'). I get the following error. Any ideas?

TypeError: MyRepository.git