kube-rsync

#!/bin/bash

# Copyright 2019 Dmitri Rubinstein
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

set -eo pipefail
export LC_ALL=C
unset CDPATH

THIS_DIR=$( (cd "$(dirname -- "${BASH_SOURCE[0]}")" && pwd -P))

# shellcheck source=kube-shlib.sh
source "$THIS_DIR/kube-shlib.sh"

define-kubectl-funcs

if [[ "$1" == "--as-rsh" ]]; then
    shift 1
    if [[ "$1" == "-l" ]]; then
        RSYNC_USER=$2
        shift 2
    fi
    RSYNC_HOST=$1
    shift 1

    if [[ -n "$RSYNC_USER" ]]; then
        POD_NAME_PREFIX=$RSYNC_USER
        if [[ -n "$RSYNC_HOST" ]]; then
            POD_NAMESPACE=$RSYNC_HOST
        fi
    else
        POD_NAME_PREFIX=$RSYNC_HOST
    fi
    if ! POD_NAME=$(wait-for-pod ${POD_NAMESPACE:+--namespace $POD_NAMESPACE} --trials 1 --run-checks 0 --delay 0 "$POD_NAME_PREFIX");
    then
        echo >&2 "Error: no pod with prefix $POD_NAME_PREFIX found in namespace $POD_NAMESPACE"
        exit 1
    fi

    echo >&2 "* Connect to pod $POD_NAME in namespace $POD_NAMESPACE"
    set -x
    # shellcheck disable=2086
    exec "${KUBECTL}" ${KUBECTL_OPTS} ${KUBE_CONTEXT:+--context=${KUBE_CONTEXT}} \
        exec \
        ${POD_NAMESPACE:+--namespace=${POD_NAMESPACE}} \
        ${POD_CONTAINER:+--container=${POD_CONTAINER}} \
        "${POD_NAME}" -i -- /bin/sh -c "eval \"\$@\"" sh "$@"
fi

usage() {
    echo "Rsync to/from the k8s pod"
    echo ""
    echo "$(basename "$0") [options] [--] [rsync-options] src_path dest_path"
    echo ""
    echo "paths starting with 'pod-name-prefix[@pod-namespace]:' are remote on specified pod"
    echo ""
    echo "environment variables:"
    echo "  KUBECTL                    Name of the kubectl command to use"
    echo "  KUBECTL_BIN                Full path to the kubectl binary. This variable has precedence over KUBECTL"
    echo "  KUBE_CONTEXT               The name of the kubeconfig context to use"
    echo "  KUBECTL_OPTS               Additional options for kubectl"
    echo ""
    echo "options:"
    echo "  -n, --namespace=''         Namespace of the pod"
    echo "      --context=''           The name of the kubeconfig context to use."
    echo "                             Has precedence over KUBE_CONTEXT variable."
    echo "  -c, --container=''         Container name. If omitted, the first container in the pod will be chosen"
    echo "      --help                 Display this help and exit"
    echo "      --                     End of options"
}

POD_NAMESPACE=$(kube-current-namespace)
POD_CONTAINER=

while [[ $# -gt 0 ]]; do
    case "$1" in
    --context)
        KUBE_CONTEXT="$2"
        shift 2
        ;;
    --context=*)
        KUBE_CONTEXT="${1#*=}"
        shift
        ;;
    -c | --container)
        POD_CONTAINER="$2"
        shift 2
        ;;
    --container=*)
        POD_CONTAINER="${1#*=}"
        shift
        ;;
    -n | --namespace)
        POD_NAMESPACE="$2"
        shift 2
        ;;
    --namespace=*)
        POD_NAMESPACE="${1#*=}"
        shift
        ;;
    --help)
        usage
        exit
        ;;
    --)
        shift
        break
        ;;
    -*)
        break # possibly rsync option
        ;;
    *)
        break
        ;;
    esac
done

export KUBECTL KUBECTL_OPTS KUBE_CONTEXT POD_NAMESPACE POD_CONTAINER

set -x
rsync -avur --blocking-io --rsh="$0 --as-rsh" "$@"