Nginx git smart http protocol (git-http-backend) configuration with basic authentication. Need the support of fcgiwrap.

server-git.conf

# Example nginx + git HTTP Smart mode (git-http-backend) + HTTP Authentication + HTTPS redirect
# Forked from jeroen@massar.ch - http://jeroen.massar.ch
# Preparation: you need to install and configure fcgiwrap and set it to listen at fcgiwrap.socket.
# 	An example tutorial: https://www.howtoforge.com/serving-cgi-scripts-with-nginx-on-centos-6.0-p2
#	A useful hint: add -f as a parameter to fcgiwrap to redirect the cgi errors to your nginx error log.
 
server {
	listen 80;
	server_name git.example.com;
 
	# Redirect all non-HTTPS traffic to the HTTPS variant
	return 301 https://$host$request_uri;
}
 
server {
	listen  443;
 	server_name git.example.com;
 	
 	# The root here have nothing to do with your git repository path.
	root /www/example/;
	index index.html;
 
        access_log /var/log/nginx/git.example.com.log;
        error_log /var/log/nginx/git.example.com_error.log info;
 
  	# Turn on ssl and set ssl params
  	ssl on;
        ssl_certificate /etc/nginx/ssl-bundle-git.crt;
        ssl_certificate_key /etc/nginx/server.key;
 
 	# Create .htpasswd by
 	#	sudo htpasswd -c /srv/websites/.htpasswd username
 	#	Note that this will replace existed .htpasswd file.
	auth_basic            "Restricted";
	auth_basic_user_file  /www/.htpasswd;
 
	# Match by regex, case sensitive. This will match URL with .git in.
	# 	For example: git.example.com/someRepo.git/info/refs...
	# 	Change this pattern to suit your needs.
	#	If you see PROPFIND in your access log then your request is not processed by git-http-backend.
	#	This may because your url didn't match the pattern,
	#		therefore all content inside the location block is not reached.
	location ~ \.git {
    		# Set chunks to unlimited, as the body's can be huge
		client_max_body_size			0;
 
		include		fastcgi_params;
		fastcgi_param	SCRIPT_FILENAME		/usr/libexec/git-core/git-http-backend;
		fastcgi_param	GIT_HTTP_EXPORT_ALL	"";
		fastcgi_param	GIT_PROJECT_ROOT	/srv/git;
		fastcgi_param	PATH_INFO		$uri;
	
		# Forward REMOTE_USER as we want to know when we are authenticated
		fastcgi_param	REMOTE_USER		$remote_user;
		fastcgi_pass	unix:/var/run/fcgiwrap.socket;
	}
}