Add Python 3.6 Jenkins slaves (#126)

* Initial commit of Python slave

* Build Python container like SCL

* Add .rhel7 Dockerfile

* Add prepare-yum-repositories

* ...and make it executable

* stop trying to remove logos if it doesn't work

* Add reference to SCL in readme

jenkins-slaves/jenkins-slave-python/Dockerfile

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+FROM openshift/jenkins-slave-base-centos7
+
+EXPOSE 8080
+
+ENV PYTHON_VERSION=3.6 \
+    PATH=$HOME/.local/bin/:$PATH \
+    PYTHONUNBUFFERED=1 \
+    PYTHONIOENCODING=UTF-8 \
+    LC_ALL=en_US.UTF-8 \
+    LANG=en_US.UTF-8 \
+    PIP_NO_CACHE_DIR=off
+
+RUN INSTALL_PKGS="rh-python36 rh-python36-python-devel rh-python36-python-setuptools rh-python36-python-pip nss_wrapper \
+        httpd24 httpd24-httpd-devel httpd24-mod_ssl httpd24-mod_auth_kerb httpd24-mod_ldap \
+        httpd24-mod_session atlas-devel gcc-gfortran libffi-devel libtool-ltdl enchant" && \
+    yum install -y centos-release-scl && \
+    yum -y --setopt=tsflags=nodocs install --enablerepo=centosplus $INSTALL_PKGS && \
+    rpm -V $INSTALL_PKGS && \
+    # Remove centos-logos (httpd dependency) to keep image size smaller.
+    rpm -e --nodeps centos-logos && \
+    yum -y clean all --enablerepo='*' && \
+    source scl_source enable rh-python36 && \
+    scl enable rh-python36 bash
+
+ADD scl_enable /usr/share/container-scripts/
+ENV BASH_ENV=/usr/share/container-scripts/scl_enable \
+    ENV=/usr/share/container-scripts/scl_enable \
+    PROMPT_COMMAND=". /usr/share/container-scripts/scl_enable"
+
+USER 1001

jenkins-slaves/jenkins-slave-python/Dockerfile.rhel7

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+FROM openshift3/jenkins-slave-base-rhel7
+
+EXPOSE 8080
+
+ENV PYTHON_VERSION=3.6 \
+    PATH=$HOME/.local/bin/:$PATH \
+    PYTHONUNBUFFERED=1 \
+    PYTHONIOENCODING=UTF-8 \
+    LC_ALL=en_US.UTF-8 \
+    LANG=en_US.UTF-8 \
+    PIP_NO_CACHE_DIR=off
+
+ADD prepare-yum-repositories prepare-yum-repositories
+
+RUN INSTALL_PKGS="rh-python36 rh-python36-python-devel rh-python36-python-setuptools rh-python36-python-pip nss_wrapper \
+        httpd24 httpd24-httpd-devel httpd24-mod_ssl httpd24-mod_auth_kerb httpd24-mod_ldap \
+        httpd24-mod_session atlas-devel gcc-gfortran libffi-devel libtool-ltdl enchant" && \
+    yum install -y yum-utils && \
+    ./prepare-yum-repositories rhel-server-rhscl-7-rpms && \
+    yum -y --setopt=tsflags=nodocs install $INSTALL_PKGS && \
+    rpm -V $INSTALL_PKGS && \
+    yum -y clean all --enablerepo='*' && \
+    source scl_source enable rh-python36 && \
+    scl enable rh-python36 bash
+
+ADD scl_enable /usr/share/container-scripts/
+ENV BASH_ENV=/usr/share/container-scripts/scl_enable \
+    ENV=/usr/share/container-scripts/scl_enable \
+    PROMPT_COMMAND=". /usr/share/container-scripts/scl_enable"
+
+USER 1001

jenkins-slaves/jenkins-slave-python/README.md

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+# jenkins-slave-python
+Provides a docker image of the python runtime for use as a Jenkins slave.
+
+## Build local
+`docker build -t jenkins-slave-python .`
+
+## Run local
+For local running and experimentation run `docker run -i -t jenkins-slave-python /bin/bash` and have a play once inside the container.
+
+## Build in OpenShift
+```bash
+oc process -f ../templates/jenkins-slave-generic-template.yml \
+    -p NAME=jenkins-slave-python \
+    -p SOURCE_CONTEXT_DIR=jenkins-slaves/jenkins-slave-python \
+    -p DOCKERFILE_PATH=Dockerfile
+    | oc create -f -
+```
+For all params see the list in the `../templates/jenkins-slave-generic-template.yml` or run `oc process --parameters -f ../templates/jenkins-slave-generic-template.yml`.
+
+## Jenkins
+Add a new Kubernetes Container template called `jenkins-slave-python` (if you've build and pushed the container image locally) and specify this as the node when running builds. If you're using the template attached; the `role: jenkins-slave` is attached and Jenkins should automatically discover the slave for you. Further instructions can be found [here](https://docs.openshift.com/container-platform/3.7/using_images/other_images/jenkins.html#using-the-jenkins-kubernetes-plug-in-to-run-jobs). Python installation commands are slightly modified from the SCL versions, which can be found [here](https://github.com/sclorg/s2i-python-container/tree/master/3.6).

jenkins-slaves/jenkins-slave-python/prepare-yum-repositories

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+#!/bin/bash
+
+# This script is used to prepare yum repositories, that are given as arguments.
+# It is no-op if user also mounts the repo file(s) into the container during
+# image build.  This can be done by one of those commands:
+#
+#   docker build -v /some/repo/file:/etc/yum.repos.d/sclorg_custom.repo
+#   docker build -v /some/repo/directory:/etc/yum.repos.d
+#   make CUSTOM_REPO=/some/repo/file/or/directory
+#
+# The last one works for projects where we have Makefile with the
+# container-common-scripts support.
+
+set -ex
+
+# DEFAULT_REPOS and SKIP_REPOS_{ENABLE,DISABLE} are intentionally undocumented,
+# but might be used if we need to change this behaviour.
+# Once we realize there are real use cases for using those variables, we should
+# document them properly.
+DEFAULT_REPOS=${DEFAULT_REPOS:-"rhel-7-server-rpms rhel-7-server-optional-rpms"}
+SKIP_REPOS_ENABLE=${SKIP_REPOS_ENABLE:-false}
+SKIP_REPOS_DISABLE=${SKIP_REPOS_DISABLE:-false}
+
+function is_subscribed() {
+  for f in /run/secrets/etc-pki-entitlement/*.pem ; do
+    [ -e "$f" ] && return 0
+    break
+  done
+  return 1
+}
+
+# DEBUGGING CASE!  Mostly for 'make CUSTOM_REPO=/some/file/or/dir'.
+test ! -f /etc/yum.repos.d/sclorg_custom.repo && \
+! mountpoint /etc/yum.repos.d \
+    || exit 0
+
+# install yum-utils for yum-config-manager
+yum install -y yum-utils
+
+if [ "$SKIP_REPOS_DISABLE" = false ] && is_subscribed; then
+  # Disable only repos that might come from subscribed host, because there
+  # might be other repos provided by user or build system
+
+  disable_repos=
+  # Lines look like: "Repo-id  :  dist-tag-override/x86_64"
+  while IFS=' /' read -r _ _ repo_id _; do
+      case $repo_id in rhel-*)
+        disable_repos+=" $repo_id" ;;
+      esac
+  done <<<"$(yum repolist -v 2>/dev/null | grep Repo-id)"
+
+  if test -n "$disable_repos"; then
+    yum-config-manager --disable $disable_repos &> /dev/null
+  fi
+fi
+
+if [ ${SKIP_REPOS_ENABLE} = false ] && [ -n "${DEFAULT_REPOS}" -o $# -gt 0 ] ; then
+  yum-config-manager --enable ${DEFAULT_REPOS} "$@"
+fi

jenkins-slaves/jenkins-slave-python/scl_enable

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+unset BASH_ENV PROMPT_COMMAND ENV
+source scl_source enable rh-python36