NSS library written in golang will not work properly because of a fork() in parent. Go runtime is asynchronous and forking such a process is impossible.
This code hangs on goroutine in net.Dial().

NSS module for rest/http.

Configureation\
/etc/nsswitch.conf:

passwd:         compat http
group:          compat http
shadow:         compat http

/etc/nsshttp.conf:

HTTPSERVER=https://si.rd.aorti.ru/api/nss
TIMEOUT=3
#DEBUG=true

Endpoints\
/passwd

[
    {
        "pw_name": "iivanov",
        "pw_passwd": "x",
        "pw_uid": 1111,
        "pw_gid": 2222,
        "pw_gecos": "Ivan Ivanov",
        "pw_dir": "/home/iivanov",
        "pw_shell": "/bin/bash"
    }
]

/shadow

[
    {
        "sp_namp": "iivanov",
        "sp_pwdp": "0000000000000000000000000000000000000000000000000000000",
        "sp_lstchg": 12345,
        "sp_min": 0,
        "sp_max": 99999,
        "sp_warn": 7,
        "sp_inact": null,
        "sp_expire": null,
        "sp_flag": null
    }
]

/group

[
    {
        "gr_name": "admins",
        "gr_passwd": "x",
        "gr_gid": 3333,
        "gr_mem": [
            "iivanov"
        ]
    }
]