installing dlib in Ubuntu 16.04 gives an error

[sukshifr]

I am trying to install dlib package on Ubuntu 16.04 and it gives me below error

RUN add-apt-repository ppa:kagamih/dlib

error:
Step 7/49 : RUN add-apt-repository ppa:kagamih/dlib
 ---> Running in c4da01f13262
 A toolkit for making real world machine learning and data analysis applications in C++ http://dlib.net https://github.com/davisking/dlib

Compiled with Intel Math Kernel Library (nonfree).

Source package repository: https://github.com/Kagami/dlib-debian
 More info: https://launchpad.net/~kagamih/+archive/ubuntu/dlib
gpg: keybox '/tmp/tmptsrq7_0_/pubring.gpg' created
gpg: /tmp/tmptsrq7_0_/trustdb.gpg: trustdb created
gpg: key 969C9178EAF40ED9: public key "Launchpad PPA for Kagami Hiiragi" imported
gpg: Total number processed: 1
gpg:               imported: 1
Warning: apt-key output should not be parsed (stdout is not a terminal)
gpg: no valid OpenPGP data found.
Removing intermediate container c4da01f13262
 ---> d2b5083516e2
Step 8/49 : RUN apt-get update
 ---> Running in dfa9aa363896
Hit:1 http://security.debian.org/debian-security stretch/updates InRelease
Ign:2 http://deb.debian.org/debian stretch InRelease
Hit:3 http://deb.debian.org/debian stretch-updates InRelease
Hit:4 http://deb.debian.org/debian stretch Release
Ign:5 http://ppa.launchpad.net/kagamih/dlib/ubuntu disco InRelease
Ign:7 http://ppa.launchpad.net/kagamih/dlib/ubuntu disco Release
Ign:8 http://ppa.launchpad.net/kagamih/dlib/ubuntu disco/main all Packages
Ign:9 http://ppa.launchpad.net/kagamih/dlib/ubuntu disco/main amd64 Packages
Ign:8 http://ppa.launchpad.net/kagamih/dlib/ubuntu disco/main all Packages
Ign:9 http://ppa.launchpad.net/kagamih/dlib/ubuntu disco/main amd64 Packages
Ign:8 http://ppa.launchpad.net/kagamih/dlib/ubuntu disco/main all Packages
Ign:9 http://ppa.launchpad.net/kagamih/dlib/ubuntu disco/main amd64 Packages
Ign:8 http://ppa.launchpad.net/kagamih/dlib/ubuntu disco/main all Packages
Ign:9 http://ppa.launchpad.net/kagamih/dlib/ubuntu disco/main amd64 Packages
Ign:8 http://ppa.launchpad.net/kagamih/dlib/ubuntu disco/main all Packages
Ign:9 http://ppa.launchpad.net/kagamih/dlib/ubuntu disco/main amd64 Packages
Ign:8 http://ppa.launchpad.net/kagamih/dlib/ubuntu disco/main all Packages
Err:9 http://ppa.launchpad.net/kagamih/dlib/ubuntu disco/main amd64 Packages
  404  Not Found
Reading package lists...
W: The repository 'http://ppa.launchpad.net/kagamih/dlib/ubuntu disco Release' does not have a Release file.
E: Failed to fetch http://ppa.launchpad.net/kagamih/dlib/ubuntu/dists/disco/main/binary-amd64/Packages  404  Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.
The command '/bin/sh -c apt-get update' returned a non-zero code: 100

What am I doing wrong?

[vavilen84]

Hi! I suppose that you take docker image golang that use ubuntu 19.04 with name "disco". You should take docker image that use ubuntu 16.04("xenial") or ubuntu 18.04("bionic") according to "ppa:kagamih/dlib" releases. Worked for me: I have taken "ubuntu:xenial" docker image and installed golang on it. Hope it could resolve your problem!