Libgit2 - Failed to authenticate SSH session: Unable to open public key file

Question

I'm trying to do a very simple git clone using ssh over a network with Libgit2 -- getting the error in the title in the process. I am not sure what I'm doing wrong -- it is not a network issue as I can clone the repo via the command line. The keys are also in the specified path.

Also the keys are already set up such that if I wanted to ssh to the machine I'm trying to clone from I just need to supply a password, so not really sure why I need to redefine it here.

#include <git2.h>
#include <iostream> 

// Callback function
int cred_cb(git_cred **out, const char *url, const char *username_from_url,
     unsigned int allowed_types, void *payload) {

  // https://libgit2.github.com/libgit2/#HEAD/group/cred/git_cred_ssh_key_new
  return git_cred_ssh_key_new(out, "username", 
        "~/.ssh/id_rsa.pub", "~/.ssh/id_rsa", "password");
}

int main() {
  // Start up libgit2
  git_libgit2_init();

  // Test clone setup
  git_repository *repo = NULL;
  const char *url = "ssh://[email protected]/home/git_repo_to_clone";
  const char *path = "tmp";

  // Test clone
  git_clone_options clone_opts = GIT_CLONE_OPTIONS_INIT;
  clone_opts.fetch_opts.callbacks.credentials = cred_cb;
  int error = git_clone(&repo, url, path, &clone_opts);

  // Prints the last error message
  std::cout << giterr_last()->message << std::endl;

  // Clean up
  git_libgit2_shutdown();

  return 0;
}

Printing allowed_types in cred_cb says 22, and so if you try to return a different type of git_cred (for example, git_cred_userpass_plaintext) the library complains that callback returned unsupported credentials type, and also if no callback is specified (by calling git_clone with NULL as the third parameter) then it says that authentication required but no callback set. I might be missing something obvious, I would appreciate any help, thanks.

Edit

I instead tried with git_cred_ssh_key_from_agent(out, "username") and it seems to have done something (the git folder gets cloned), albeit with missing files. Although now the problem is it becomes an endless loop between cred_cb and git_clone (seems to be called back and forth).

Answer 1

The path to the key files should be the full path without ~. Libgit2 doesn't expand ~ like the shell would.

Also, the password should be the passphrase used to encrypt your private key, not the password you use to authenticate with the remote.