An example of how to build grafana tanka image and use it as a standalone out of the box tanka cli convenient for CI automation.

Dockerfile.tanka

# https://stackoverflow.com/questions/56645546/from-as-in-dockerfile-not-working-as-i-expect
# Installing jsonnet-bundler

FROM golang:alpine AS go_jb

RUN apk --no-cache add git
RUN go get -u github.com/jsonnet-bundler/jsonnet-bundler/cmd/jb

# Installing docker & kubectl

FROM docker:latest

RUN apk --no-cache add curl git

# Copying jsonnet-bundler

RUN mkdir -p /go/bin

COPY --from=go_jb /go/bin/jb /go/bin/

ENV PATH="/go/bin:${PATH}"

# Installing kubctl & tanka

RUN curl -L -o /usr/local/bin/kubectl "https://storage.googleapis.com/kubernetes-release/release/`curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt`/bin/linux/amd64/kubectl" \
    && chmod a+x /usr/local/bin/kubectl

RUN curl -L -o /usr/local/bin/tk "https://github.com/grafana/tanka/releases/download/v0.8.0/tk-linux-amd64" \
    && chmod a+x /usr/local/bin/tk

ENTRYPOINT [ "/usr/local/bin/tk" ]

tanka.sh

#!/bin/bash

image="tanka:alpine"
cmd=''
path=$(pwd)

for arg in "$@"; do
    case $arg in
        -b | --build ) build=true; shift ;;
        -p* | --path* )
        path="${arg#*=}";
        path="$(cd $(dirname $path)/$(basename $path) && pwd)";
        shift
        ;;
        * ) cmd="$cmd $1"; shift ;;
    esac
done

if [[ $build == true ]]; then
    docker build --rm -f Dockerfile.tanka -t $image .
    docker rmi -f $(docker images -qa -f 'dangling=true') # cleanup
fi

if [[ $cmd != '' ]]; then
    config='/data/.cluster.config'
    docker run \
        --rm \
        --net=host \
        --name tanka \
        -v $path:/data:rw \
        -w /data \
        -e KUBECONFIG="$config" \
        -e PAGER="more" \
        -it \
        $image \
        $cmd
fi