Creates a shell into an AWS ECS container

ecs-container-exec.sh

#!/usr/bin/env bash

# Enable strict mode
# http://redsymbol.net/articles/unofficial-bash-strict-mode/
set -euo pipefail
IFS=$'\n\t'

usage () {
    cat <<EOF
Usage: $(basename "$0") cluster-name [command to execute]

Example usage: $(basename "$0") iss4-dev ls /

Description: Executes a command in an ECS container. If "command to execute"
    is not given then "bash" will be used. Use the AWS_PROFILE environment
    variable to set the profile for AWS CLI to use.
    
    To sepcify the profile as a quick one-liner you can prefix with 
    \`env AWS_PROFILE=\$NAME_OF_PROFILE_TO_USE\`. For example
    \`env AWS_PROFILE=ds-iss-test $(basename "$0") iss3-test\`.
EOF
}

usage_as_additional_info () {
    echo ""
    echo "--------------------------------------------------------------------------------"
    usage
}

if [[ "${1:-}" == "--help" ]]; then
    usage
    exit 0;
fi

if [[ -z "${1:-}" ]]; then
    echo "Error: Missing first argument." >&2
    usage_as_additional_info
    exit 1
fi
if [[ -z "${2:-}" ]]; then
    echo "Error: Missing second argument." >&2
    usage_as_additional_info
    exit 1
fi

CLUSTER=${1:-}
shift 1
# Default command to "bash" if not given
if [ -z "${1:-}" ]; then
    set -- "bash"
fi
COMMAND="$(printf ' %q' "$@")"

# Refresh aws token if previously issued token has expired
set +o pipefail
if aws configure list 2>&1 | grep -q 'run aws sso login' && true; then
    aws sso login
fi
set -o pipefail

AWS_CONFIG_LIST=$(aws configure list | sed 's/^[ \t]*//')

CURRENT_AWS_PROFILE=$(echo "$AWS_CONFIG_LIST" | awk '$1 == "profile"' | awk '{print $2}')
CURRENT_AWS_ACCESS_KEY=$(echo "$AWS_CONFIG_LIST" | awk '$1 == "access_key"' | awk '{print $2}')

if [ "$CURRENT_AWS_ACCESS_KEY" == "<not" ]; then
    if [ "$CURRENT_AWS_ACCESS_KEY" == "<not" ]; then
        echo "Error: AWS CLI profile not set and no credentials not found. Please set the AWS_PROFILE environment variable used by AWS CLI." >&2
    else
        echo "Error: AWS CLI profile set to \"$CURRENT_AWS_PROFILE\" but no credentials not found." >&2
    fi
    exit 1
fi

get_running_containers() {
    TASKS_LIST_STDOUT=$(mktemp)
    set +e # Disable exit on non-zero return since we want to do things if we get an error
    TASKS_LIST=$(aws ecs list-tasks --cluster "$CLUSTER" --output text 2>"$TASKS_LIST_STDOUT")
    TASKS_LIST_EXIT_CODE=$?
    if [ "$TASKS_LIST_EXIT_CODE" != "0" ]; then
        if grep -q "Cluster not found" < "$TASKS_LIST_STDOUT"; then
            echo "The ECS cluster \"$CLUSTER\" not found using AWS CLI profile of \"$CURRENT_AWS_PROFILE\"" >&2
            exit 1
        else
            cat "$TASKS_LIST_STDOUT" >&2
            rm "$TASKS_LIST_STDOUT"
            exit 1
        fi
    fi
    set -e # Re-enable exit on non-zero return
    TASK_IDS=$(awk '{print $2}' <<<"$TASKS_LIST");
    # Get container-level details, append task-level createdAt and taskDefinitionArnonly, then extract last segument of containerArn, taskArn and image
    aws ecs describe-tasks --cluster "$CLUSTER" --tasks $TASK_IDS \
        --query "tasks[][containers[?lastStatus=='RUNNING'][name, containerArn, taskArn, image]][][]" --output text \
        | xargs -S "$(getconf ARG_MAX)" "-I{}" -- bash -c 'printf "%s %s %s\n" "$0" $(aws ecs describe-tasks --cluster "'"$CLUSTER"'" --tasks $(awk "{print \$3}" <<<"$0") --query "tasks[0] | [createdAt, taskDefinitionArn]" --output text)' {} \
        | awk -v OFS=$'\t' '{split($2,a,"/"); $2=a[4]; split($3,a,"/"); $3=a[3]; split($4,a,":"); $4=a[2]; split($6,a,":"); $6=a[7]; print $0}' 
}

format_running_containers() {
    {
        echo -e "Container Name\tContainer Id\t\tTask Id\tImage Tag\tCreation Date\tTask Defintion";
        echo "$1"
    } | column -t -s$'\t'
}

TASKS_LIST=$(get_running_containers)

TASKS_COUNT=$(wc -l <<<"$TASKS_LIST" | awk '{print $1}')

if [ "$TASKS_COUNT" -gt "1" ]; then
    echo "The ECS cluster \"$CLUSTER\" has more than 1 task. Which one would you like to execute the command in?";
    echo ""
    
    TASK_IDS=$(awk '{print $2}' <<<"$TASKS_LIST");
    
    # readarray requires bash 4 and later
    readarray -t TASKS_TABLE < <(format_running_containers "$TASKS_LIST")
    # Print headers
    echo "  " "${TASKS_TABLE[@]:0:1}"
    PS3=$'\nTask line number: '
    select TASK_LINE in "${TASKS_TABLE[@]:1}"; do
        TASK_ID=$(awk '{print $3}' <<<"$TASK_LINE")
        CONTAINER_NAME=$(awk '{print $1}' <<<"$TASK_LINE")
        break;
    done
elif [ "$TASKS_COUNT" == 0 ]; then
    echo "The ECS cluster \"$CLUSTER\" has no tasks." 1>&2
    exit 1
else
    TASK_ID=$(awk '{print $3}' <<<"$TASKS_LIST")
    CONTAINER_NAME=$(awk '{print $1}' <<<"$TASKS_LIST")
fi

exec aws ecs execute-command --cluster "$CLUSTER" --task "$TASK_ID"  --container "$CONTAINER_NAME" --interactive --command "$COMMAND"