DevOps-Bash-tools/.bash.d/kubernetes.sh

#!/usr/bin/env bash
#  vim:ts=4:sts=4:sw=4:et
#
#  Author: Hari Sekhon
#  Date: 2019-07-28 14:56:41 +0100 (Sun, 28 Jul 2019)
#
#  https://github.com/harisekhon/bash-tools
#
#  License: see accompanying Hari Sekhon LICENSE file
#
#  If you're using my code you're welcome to connect with me on LinkedIn and optionally send me feedback to help steer this or other code I publish
#
#  https://www.linkedin.com/in/harisekhon
#

# ============================================================================ #
#                  K u b e r n e t e s   /   O p e n S h i f t
# ============================================================================ #

for x in kubectl oc; do
    if type -P "$x" &>/dev/null; then
        # shellcheck disable=SC1090
        source <("$x" completion bash)
    fi
done

# minishift oc-env > ~/.minishift.env
if [ -f ~/.minishift.env ]; then
    # remove .minishift.env if it causes errors, which can happen if it was generated when there was no MiniShift VM running
    # shellcheck disable=SC1090
    . ~/.minishift.env || rm -f ~/.minishift.env
fi

#if [ -f "/usr/local/opt/kube-ps1/share/kube-ps1.sh" ]; then
#    . "/usr/local/opt/kube-ps1/share/kube-ps1.sh"
#    # overriden in prompt.sh which is evaluated later so this is sourced there
#    #PS1='$(kube_ps1)'" $PS1"
#fi

# ============================================================================ #

# 'k8s-app' label is set by dashboard creation but who uses that
k8s_get_pod_opts="-o wide -L app,env"

alias po='k get po $k8s_get_pod_opts'
alias kapply='k apply -f'
alias kapp=kapply
alias wp=watchpods
alias ke=kubeexec
alias kg='k get'
alias ka='k apply'
alias kl='k logs'
alias kshell='kube-shell'
alias kubesh='kube-shell'

alias use="k config use-context"
alias contexts="k config get-contexts"
#alias context="k config current-context"
context(){ k config current-context; }
# contexts has this info and is more useful
#alias clusters="k config get-clusters"

alias kcd='k config set-context $(kubectl config current-context) --namespace'

alias menv='eval $(minikube docker-env)'

# ============================================================================ #

kubectl_opts="${KUBECTL_OPTS:-}"
# set K8S_NAMESPACE in local .bashrc or similar files for environments where your ~/.kube/config
# gets regenerated daily with certification authentication from a kerberos login script, which
# resets the 'kcd bigdata' namespace change. This way you automatically send the right namespace every time
if [ "${K8S_NAMESPACE:-}" ]; then
    kubectl_opts="-n $K8S_NAMESPACE"
fi
# TODO: might split this later
oc_opts="$kubectl_opts"

# ============================================================================ #

# oc() and kubectl() fix future invocations of k() to the each command if you want to explicitly switch between them
oc(){
    export KUBERNETES_CLI=oc
    # shellcheck disable=SC2086
    command oc $oc_opts "$@"
}

kubectl(){
    export KUBERNETES_CLI=kubectl
    # shellcheck disable=SC2086
    command kubectl $kubectl_opts "$@"
}

k(){
    local opts
    # more efficient than forking to check history every time
    if [ -n "$KUBERNETES_CLI" ]; then
        case "$KUBERNETES_CLI" in
            kubectl)    opts="$kubectl_opts"
                        ;;
                 oc)    opts="$oc_opts"
                        ;;
                    *)  echo "invalid command '$KUBERNETES_CLI' listed in \$KUBERNETES_CLI (must be either 'kubectl' or 'oc' depending on whether you are using straight Kubernetes or OpenShift). Fix the variable or unset it to auto-detect when calling the k() function"
                        return
                        ;;
        esac
        # shellcheck disable=SC2086
        command "$KUBERNETES_CLI" $opts "$@"
    else
        # shellcheck disable=SC2086
        case "$(k8s_or_openshift)" in
                openshift)   command oc $oc_opts "$@"
                             export KUBERNETES_CLI=oc
                             ;;
                    k8s|*)   command kubectl $kubectl_opts "$@"
                             export KUBERNETES_CLI=kubectl
                             ;;
        esac
    fi
}

krun(){
    local image="$1"
    local name="${image//\//-}"
    shift
    # sleep infinity only works on some distros
    k run --generator=run-pod/v1 "$name" --image "$image" -ti -- /bin/sh
}

kexec(){
    local line
    local name="${1//\//-}"
    if [ -z "$name" ]; then
        echo "usage: kexec <name>"
        return 1
    fi
    for ((i=0;i<100;i++)); do
        line="$(k get po | grep -F "$name")"
        if [ -z "$line" ]; then
            echo "No pod matching name $name found!"
            return 1
        fi
        name="$(awk '/Running/{print $1}' <<< "$line")"
        if [ -n "$name" ]; then
            break
        fi
        echo "waiting for pod to start running..."
        sleep 1
    done
    k exec -ti "$name" -- /bin/sh
}

# looks like both of these work on OpenShift context
#
# 'kubectl get pods'
#
# 'oc get pods'

# figure out if we're using k8s or openshift via most recent commands - return either 'k8s' or 'openshift'
k8s_or_openshift(){
    local last_k8s_cmd
    last_k8s_cmd="$(
        history |
        grep -v history |
        grep -Eo -e '\<oc\>' \
                 -e '\<kubect[l]\>' \
                 -e '\<minikub[e]\>' \
                 -e '\<minishif[t]\>' |
        tail -n 1
    )"
    case "$last_k8s_cmd" in
            oc|minishift)   echo openshift
                            # these end up in a subshell so aren't really useful, set in k() instead
                            #export KUBERNETES_CLI=oc
                            ;;
        kubectl|minikube)   echo k8s
                            #export KUBERNETES_CLI=kubectl
                            ;;
                       *)   echo unknown
                            ;;
    esac
}

oc_get_pods(){
    # shellcheck disable=SC2086
    oc get pods $k8s_get_pod_opts
}

k8s_get_pods(){
    # shellcheck disable=SC2086
    k get pods $k8s_get_pod_opts
}

get_pods(){
    #case "$(k8s_or_openshift)" in
    #        openshift)   oc_get_pods
    #                     ;;
    #              k8s)   k8s_get_pods
    #                     ;;
    #                *)   k8s_get_pods
    #                     ;;
    #esac
    #
    # k8s functions now include k8s vs oc detection, no need for above or would end up double calling k8s_or_openshift
    k8s_get_pods
}
export -f get_pods

get_pod(){
    local filter="${1:-.*}"
    get_pods |
    grep -v '^NAME[[:space:]]' |
    grep Running |
    awk "/$filter/{print \$1; exit}"
}

watchpods(){
    # watch on Mac (brew installed) doesn't have -x switch and doesn't work on even 'export -f function'
    # leave using kubectl call for now as that works on openshift too
    watch "
        echo 'Context: '
        echo
        kubectl config current-context
        echo
        echo
        echo 'Pods:'
        echo
        kubectl $kubectl_opts get pods $k8s_get_pod_opts 2>&1
        echo
    "
}

kdesc(){
    k describe "$@"
}

kdp(){
    kdesc pods "$@"
}

kdelp(){
    k delete pod "$@"
}

kubeexec(){
    local pod
    pod="$(get_pod "$1")"
    shift
    k exec -ti "$pod" "$@" /bin/sh
}

# Getting token works on stock Kubernetes but not OpenShift due to stricter defaults
#
# Error from server (Forbidden): secrets is forbidden: User "developer" cannot list secrets in the namespace "kube-system": no RBAC policy matched
# error: resource name may not be empty
#
## even after 'oc login' as system/admin
#
# Error from server (Forbidden): secrets is forbidden: User "system" cannot list secrets in the namespace "kube-system": no RBAC policy matched
# error: resource name may not be empty
#
k8s_get_token(){
    kubectl describe secret -n kube-system \
        "$(kubectl get secrets -n kube-system | grep default | cut -f1 -d ' ')" |
    grep '^token' |
    awk '{print $2}'
}

k8s_get_api(){
    local context
    local cluster
    context="$(context)"
    cluster="$(k config view -o jsonpath="{.contexts[?(@.name == \"$context\")].context.cluster}")"
    k config view -o jsonpath="{.clusters[?(@.name == \"$cluster\")].cluster.server}"
    # or if you have jq installed:
    # k get --raw=/api | jq -r '.serverAddressByClientCIDRs[0].serverAddress'
    echo
}

# run kubectl commands against multiple clusters
kclusters(){
    for context in $(kubectl config get-contexts -o=name --kubeconfig clusters.yaml); do
        kubectl "$@" --kubeconfig clusters.yaml --context="$context"
    done
}

# to kubectl apply manifests to both clusters for multi-cluster deployments
kclustersapply(){
    kclusters apply -f "$@"  # eg. manifests
}