SSH to EC2 using peco and awless

ssh-aws-ec2-instance

#!/bin/bash

###
# SSH to AWS EC2 instances using peco and awless
#
# - Generate a cache of AWS instances 
# - Open peco to select one or more server and either open ssh or tmux-css
# - Does not use `awless ssh` since prefererence on ‘security by obscurity’
#
# Dependencies
#
#  https://github.com/peikk0/tmux-cssh
#  https://github.com/peco/peco
#  https://github.com/wallix/awless
#
# Part of bash-raclette

# Strict bash scripting
set -euo pipefail -o errtrace

# Using XDG standards ;)
CACHE_PATH="${CACHE_PATH:-$HOME/.cache/rc}"

if [[ -z "${AWS_PROFILES:-}" ]]; then
    echo "$(basename $0): No AWS_PROFILES defined"
    exit 1
fi
IFS=' ' read -r -a awsProfiles <<< "$AWS_PROFILES"

# hide up cmd output
on_exit_hide_cmd() {
    echo -e "\r\e[K\r\e[1A"
}

# output to stdin after run and press return
runcmd (){
    echo "$@" | perl -e 'ioctl STDOUT, 0x5412, $_ for split //, <>' ; 
    trap on_exit_hide_cmd EXIT
}

# output to stdin after run 
writecmd (){ 
    echo "$@" | perl -e 'ioctl STDOUT, 0x5412, $_ for split //, do{ chomp($_ = <>); $_ }' ; 
    trap on_exit_hide_cmd EXIT
}

cachefile_valid() {
    local ftime=$(stat -c %Y $1 2>/dev/null)
    if [[ -z "$ftime" ]]; then
        return 1
    fi
    # better of with printf here yet trying to be nice to osx's bash3
    local now=$(date +%s) 
    if [[ $(( ${ftime} + 3600 + 24 )) -gt ${now} ]]; then
        return 0;
    else 
        return 1
    fi
}

update_aws_instance_cache() {
    local cmd=()
    local cacheFile
    local sync=0
    if [[ ! -d "$CACHE_PATH" ]]; then
        mkdir -p "$CACHE_PATH"
    fi
    for profile in ${awsProfiles[@]}; do
        cacheFile="$CACHE_PATH/aws-$profile-instances.list"
        if ! cachefile_valid $CACHE_PATH/aws-$profile-instances.list 1; then
            cmd=(
               awless -p "$profile" list instances \
                  --columns id,name,state,keypair,privateip,publicip,tags \
                  --format=csv --sort name --no-headers '|' xargs -I {} echo $profile,{}
            )
            ( eval ${cmd[@]} > "$cacheFile.new" && mv "$cacheFile.new" "$cacheFile" ) &
            if [[ -e "$cacheFile" ]]; then
                # if file is old we background process and continue
                disown
            else
                echo "awless: generating cache for $profile"
                sync=1
            fi
        fi
        if [[ "$sync" -eq 1 ]]; then
            for job in $(jobs -p); do wait $job || ( echo "failure..." && exit 1 ); done
        fi
    done
}

list_aws_instances() {
    for profile in ${awsProfiles[@]}; do
        cat "$CACHE_PATH/aws-$profile-instances.list"
    done
}

format_aws_instance_csv() {
    printf "%s\n" "$@" | sed ':a;N;$!ba;s/\n/\n\n---\n/g' | tr ',' '\n'
}

main() {
    update_aws_instance_cache 
    IFS=$'\n' instances=($(list_aws_instances | peco --initial-filter Fuzzy --prompt "aws-instance>"))
    if [[ -z "${instances[*]}" ]]; then
        return
    fi
    format_aws_instance_csv "${instances[@]}"
    local cmd="ssh"
    echo "${#instances[@]}"
    if [[ "${#instances[@]}" -gt 1 ]]; then
        cmd="tmux-cssh"
    fi 
    cmd="${cmd} ${@} $(printf "%s\n" "${instances[@]}" | cut -d ',' -f 6 | tr '\n' ' ')"
    echo
    echo ---
    writecmd "${cmd}"
}

main "$@"