This is an image based on Alpine, containing all libraries needed to run an Oracle Client application.
The base image is frol/docker-alpine-glibc, and contains glibc to enable proprietary projects compiled against glibc (e.g. OracleJDK, Anaconda) work on Alpine.
The required files are in oracle directory.
The package instantclient_12_1.tar.gz were originally downloaded from the Oracle Site, and unnecessary files were removed.
docker build -t alpine-glibc-oracle .
To build a Golang application that uses Oracle database, I suggest you look docker-go-oci8.