rustup: Unable to run interactively. Run with -y to accept defaults, --help for additional options

https://build.snapcraft.io/user/messense/fasttext-serving/412146

[22/Dec/2018:06:02:43 +0000] "CONNECT static.rust-lang.org:443 HTTP/1.0" 200 6050 "-" "-"
info: downloading installer
[22/Dec/2018:06:02:45 +0000] "CONNECT static.rust-lang.org:443 HTTP/1.1" 200 11145131 "-" "curl/7.47.0"
rustup: Unable to run interactively. Run with -y to accept defaults, --help for additional options
Downloading 'rustup.sh' 0%
Downloading 'rustup.sh' 10%
Downloading 'rustup.sh' 20%
Downloading 'rustup.sh' 30%
Downloading 'rustup.sh' 41%
Downloading 'rustup.sh' 51%
Downloading 'rustup.sh' 61%
Downloading 'rustup.sh' 72%
Downloading 'rustup.sh' 82%
Downloading 'rustup.sh' 92%
Downloading 'rustup.sh' 100%
Downloading 'rustup.sh' 100%
/build/fasttext-serving/parts/fasttext-serving/rust/rustup.sh --prefix=/build/fasttext-serving/parts/fasttext-serving/rust --disable-sudo --save --channel=nightly
Failed to run '/build/fasttext-serving/parts/fasttext-serving/rust/rustup.sh --prefix=/build/fasttext-serving/parts/fasttext-serving/rust --disable-sudo --save --channel=nightly' for 'fasttext-serving': Exited with code 1.
Verify that the part is using the correct parameters and try again.
Build failed
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/lpbuildd/target/build_snap.py", line 230, in run
    self.pull()
  File "/usr/lib/python2.7/dist-packages/lpbuildd/target/build_snap.py", line 195, in pull
    env=env)
  File "/usr/lib/python2.7/dist-packages/lpbuildd/target/build_snap.py", line 75, in run_build_command
    return self.backend.run(args, env=full_env, **kwargs)
  File "/usr/lib/python2.7/dist-packages/lpbuildd/target/lxd.py", line 460, in run
    subprocess.check_call(cmd, **kwargs)
  File "/usr/lib/python2.7/subprocess.py", line 541, in check_call
    raise CalledProcessError(retcode, cmd)
CalledProcessError: Command '['lxc', 'exec', 'lp-xenial-amd64', '--env', 'LANG=C.UTF-8', '--env', 'SHELL=/bin/sh', '--env', 'SNAPCRAFT_LOCAL_SOURCES=1', '--env', 'SNAPCRAFT_SETUP_CORE=1', '--env', 'SNAPCRAFT_BUILD_INFO=1', '--env', 'SNAPCRAFT_IMAGE_INFO={"build_url": "https://launchpad.net/~build.snapcraft.io/+snap/e99279eb2d353f2b5163dc64cec24218-xenial/+build/412146"}', '--env', 'SNAPCRAFT_BUILD_ENVIRONMENT=host', '--env', 'http_proxy=http://10.10.10.1:8222/', '--env', 'https_proxy=http://10.10.10.1:8222/', '--env', 'GIT_PROXY_COMMAND=/usr/local/bin/snap-git-proxy', '--', '/bin/sh', '-c', 'cd /build/fasttext-serving && linux64 snapcraft pull']' returned non-zero exit status 2