Is there a way to cache GitHub credentials for pushing commits?

Question

I recently switched to synchronizing my repositories to https:// on GitHub (due to firewall issues), and it asks for a password every time.

Is there a way to cache t

Answer 1

TLDR; Use an encrypted netrc file with Git 1.8.3+.

Saving a password for a Git repository HTTPS URL is possible with a ~/.netrc (Unix) or %HOME%/_netrc (note the _) on Windows.

But: That file would store your password in plain text.

Solution: Encrypt that file with GPG (GNU Privacy Guard), and make Git decrypt it each time it needs a password (for push/pull/fetch/clone operation).

---

Note: with Git 2.18 (Q2 2018), you now can customize the GPG used to decrypt the encrypted .netrc file.

See commit 786ef50, commit f07eeed (12 May 2018) by Luis Marsano (``).
^{(Merged by Junio C Hamano -- gitster -- in commit 017b7c5, 30 May 2018)}

git-credential-netrc: accept gpg option

git-credential-netrc was hardcoded to decrypt with 'gpg' regardless of the gpg.program option.
This is a problem on distributions like Debian that call modern GnuPG something else, like 'gpg2'

---

Step-by-Step instructions for Windows

With Windows:

(Git has a gpg.exe in its distribution, but using a full GPG installation includes a gpg-agent.exe, which will memorize your passphrase associated to your GPG key.)

• Install gpg4Win Lite, the minimum gnupg command-line interface (take the most recent gpg4win-vanilla-2.X.Y-betaZZ.exe), and complete your PATH with the GPG installation directory:

  set PATH=%PATH%:C:\path\to\gpg
  copy C:\path\to\gpg\gpg2.exe C:\path\to\gpg\gpg.exe
  

(Note the 'copy' command: Git will need a Bash script to execute the command 'gpg'. Since gpg4win-vanilla-2 comes with gpg2.exe, you need to duplicate it.)

• Create or import a GPG key, and trust it:

  gpgp --import aKey
  # or
  gpg --gen-key
  

(Make sure to put a passphrase to that key.)

• Trust that key

• Install the credential helper script in a directory within your %PATH%:

  cd c:\a\fodler\in\your\path
  curl -o c:\prgs\bin\git-credential-netrc https://raw.githubusercontent.com/git/git/master/contrib/credential/netrc/git-credential-netrc.perl
  

(Beware: the script is renamed in Git 2.25.x/2.26, see below)

(Yes, this is a Bash script, but it will work on Windows since it will be called by Git.)

• Make a _netrc file in clear text

  machine a_server.corp.com
  login a_login
  password a_password
  protocol https
  
  machine a_server2.corp.com
  login a_login2
  password a_password2
  protocol https
  

(Don't forget the 'protocol' part: 'http' or 'https' depending on the URL you will use.)

• Encrypt that file:

  gpg -e -r a_recipient _netrc
  

(You now can delete the _netrc file, keeping only the _netrc.gpg encrypted one.)

• Use that encrypted file:

  git config --local credential.helper "netrc -f C:/path/to/_netrc.gpg -v"
  

(Note the '/': C:\path\to... wouldn't work at all.) (You can use at first -v -d to see what is going on.)

From now on, any Git command using an HTTP(S) URL which requires authentication will decrypt that _netrc.gpg file and use the login/password associated to the server you are contacting. The first time, GPG will ask you for the passphrase of your GPG key, to decrypt the file. The other times, the gpg-agent launched automatically by the first GPG call will provide that passphrase for you.

That way, you can memorize several URLs/logins/passwords in one file, and have it stored on your disk encrypted.
I find it more convenient than a "cache" helper", where you need to remember and type (once per session) a different password for each of your remote services, for said password to be cached in memory.

---

With Git 2.26 (Q1 2020), the sample credential helper for using .netrc has been updated to work out of the box. See patch/discussion.

See commit 6579d93, commit 1c78c78 (20 Dec 2019) by Denton Liu (Denton-L).
^{(Merged by Junio C Hamano -- gitster -- in commit 1fd27f8, 25 Dec 2019)}

contrib/credential/netrc: make PERL_PATH configurable

^{Signed-off-by: Denton Liu}

The shebang path for the Perl interpreter in git-credential-netrc was hardcoded.
However, some users may have it located at a different location and thus, would have had to manually edit the script.

Add a .perl prefix to the script to denote it as a template and ignore the generated version.
Augment the Makefile so that it generates git-credential-netrc from git-credential-netrc.perl, just like other Perl scripts.

The Makefile recipes were shamelessly stolen from contrib/mw-to-git/Makefile.

And:

With 2.26 (Q1 2020), Sample credential helper for using .netrc has been updated to work out of the box.

See commit 6579d93, commit 1c78c78 (20 Dec 2019) by Denton Liu (Denton-L).
^{(Merged by Junio C Hamano -- gitster -- in commit 1fd27f8, 25 Dec 2019)}

contrib/credential/netrc: work outside a repo

^{Signed-off-by: Denton Liu}

Currently, git-credential-netrc does not work outside of a git repository. It fails with the following error:

fatal: Not a git repository: . at /usr/share/perl5/Git.pm line 214.

There is no real reason why need to be within a repository, though. Credential helpers should be able to work just fine outside the repository as well.

Call the non-self version of config() so that git-credential-netrc no longer needs to be run within a repository.

Jeff King (peff) adds:

I assume you're using a gpg-encrypted netrc (if not, you should probably just use credential-store).
For "read-only" password access, I find the combination of pass with config like this is a bit nicer:

[credential "https://github.com"]
  username = peff
  helper = "!f() { test $1 = get && echo password=`pass github/oauth`; }; f"