#!/bin/bash
 
#
# This script uses AWS API to create RedShift clusters and snapshots.
#
 
 
#----------------- list_snapshots() --------------------------------------------------
list_snapshots()
{
    echo "List of snapshots..."
    echo "---------------------"
    echo ""
 
    arr_snapshots=(`aws redshift describe-cluster-snapshots | grep SnapshotIdentifier | awk '{ print $2 }' | sed 's/"//g' `)
    echo ${arr_snapshots[@]} | tr " " "\n" | nl
    arr_snapshots_len=${#arr_snapshots[@]}
    echo ""
}
 
#----------------- list_clusters() ---------------------------------------------------
list_clusters()
{
    echo "List of clusters..."
    echo "---------------------"
    echo ""
 
    arr_clusters=(`aws redshift describe-clusters | grep ClusterIdentifier | awk '{ print $2 }' | sed 's/,//' | sed 's/"//g' `)
    echo ${arr_clusters[@]} | tr " " "\n" | nl
    arr_clusters_len=${#arr_clusters[@]}
    echo ""
}
 
#----------------- check_confirmation() -------------------------------------------
check_confirmation()
{
    # this loop checks if nothing or empty/white string was inputted
    while [ 1 ]
    do
        printf "Do you want to proceed? (y/n): "
        read response
        [ ! -z "$response" ] && break
    done
 
    [ "$response" ==  "n" ] && continue || [ "$response" !=  "y" ] && break
}
 
#-------------------------------------------------------------------------------------
 
main_menu()
{
    echo "What would you like to do?"
    echo "=========================="
    echo ""
    echo "     (1) List clusters"
    echo "     (2) List snapshots"
    echo "     (3) Create cluster from snapshot"
    echo "     (4) Create snapshot from cluster (also deletes the cluster)"
    echo "     (5) Quit"
    echo ""
}
 
#----------------- start main loop ---------------------------------------------------
 
clear
 
# Display snapshots and clusters
list_snapshots
list_clusters
 
# This loop runs continuously until user enters q to quit
while [ 1 ];
do
    # Display menu choices
    main_menu
 
    # read user choice
    printf "Choice: "
    read input
    echo ""
 
    case "$input" in
        (1) # display clusters
            list_clusters
            continue
            ;;
        (2) # display snapshots
            list_snapshots
            continue
            ;;
        (3) # Create cluster from snapshot
            echo "You chose to create a cluster from a snapshot.  Which snapshot do you want to use? Number: "
            echo ""
            list_snapshots
 
            echo "     b  Back to main menu"
            echo ""
            printf "Which snapshot do you want to use to create a cluster? Number: "
            read input
            re='^[0-9qb]+$'   # regular expression
            while ! [[ $input =~ $re ]]
            do
                echo ""
                echo "Not a valid choice.  Please try again."
                echo ""
                echo ${arr_snapshots[@]} | tr " " "\n" | nl
                echo ""
                echo "     b  Back to main menu"
                echo ""
                printf "Which snapshot do you want to use to create a cluster? Number: "
                read input
 
                # if input contains a space, go back to top of while-loop
                [[ $input = *[[:space:]]*  ]] && continue
 
            done
 
            [ $input == "q" ] && echo "Goodbye" && exit
            [ $input == "b" ] && continue
 
            while [ $input -gt $arr_snapshots_len ] || [ $input -lt "1" ] || ! [[ $input =~ $re ]]
            do
                echo ""
                echo "Not a valid choice.  Please try again."
                echo ""
                echo ${arr_snapshots[@]} | tr " " "\n" | nl
                echo ""
                echo "     b  Back to main menu"
                echo ""
                printf "Which snapshot do you want to use to create a cluster? Number: "
                read input
            done
 
            choice=`expr $input - 1`
            snapshot_choice=${arr_snapshots[${choice}]}
            echo "You chose "$snapshot_choice
            echo ""
 
            # if user hits return without typing anything, re-ask question.
            while [ 1 ]
            do
                printf "Please enter cluster name: "
                read cluster_name
 
                # replace any spaces with dash
                    cluster_name=`echo $cluster_name | sed 's/ /-/g'`
                [ ! -z "$cluster_name" ] && break
            done
 
            cmd="aws redshift restore-from-cluster-snapshot --cluster-identifier $cluster_name --snapshot-identifier $snapshot_choice"
 
            echo "About to execute the following command:"
            echo ""
            echo $cmd
            echo ""
 
            # confirm to continue
            check_confirmation
 
            echo "Creating cluster: $cluster_name.  Please wait.  This will take some time..."
            eval $cmd
            echo ""
 
            # display message again after json ouput
            echo "Creating cluster: $cluster_name.  Please wait.  This will take some time..."
 
            # check when cluster creation is done.  Echo out running counter to show progress.
            count=0
            while [ 1 ]
            do
               aws redshift describe-clusters --cluster-identifier $cluster_name | grep ClusterStatus | grep available > /dev/null
               if [ $? -eq 0 ]
               then
                break
               fi
               count=`expr $count + 1`
               printf "$count "
               sleep 2
            done
            echo ""
            echo "Cluster $cluster_name created."
            echo ""
 
            # show list of clusters. It will now include new cluster.
            list_clusters
 
            continue
            ;;
 
        (4) # Create snapshot from cluster
            echo "You chose to create snapshot from a cluster.  Which cluster do you want to use? Number: "
            echo ""
            list_clusters
 
            echo "     b  Back to main menu"
            echo ""
            printf "Which cluster do you want to use to create a snapshot? Number: "
            read input
            re='^[0-9qb]+$'   # regular expression
            while ! [[ $input =~ $re ]]
            do
                echo ""
                echo "Not a valid choice.  Please try again."
                echo ""
                echo ${arr_clusters[@]} | tr " " "\n" | nl
                echo ""
                echo "     b  Back to main menu"
                echo ""
                echo ""
                printf "Which cluster do you want to use to create a snapshot? Number: "
                read input
                # if input contains a space, go back to top of while-loop
                [[ $input = *[[:space:]]*  ]] && continue
            done
 
            [ $input == "q" ] && echo "Goodbye" && exit
            [ $input == "b" ] && continue
 
            while [ $input -gt $arr_clusters_len ] || [ $input -lt "1" ] || ! [[ $input =~ $re ]]
            do
                #echo "There are only $arr_clusters_len clusters.  Please choose again."
                echo ""
                echo "Not a valid choice.  Please try again."
                echo ""
                echo ${arr_clusters[@]} | tr " " "\n" | nl
                echo ""
                echo "     b  Back to main menu"
                echo ""
                printf "Which cluster do you want to use to create a snapshot? Number: "
 
                read input
            done
 
            choice=`expr $input - 1`
            cluster_choice=${arr_clusters[${choice}]}
            echo "You chose "$cluster_choice
            echo ""
 
            # if user hits return without typing anything, re-ask question.
            while [ 1 ]
            do
                printf "Please enter snapshot name: "
                read snapshot_name
 
                # replace any spaces with dash
                    snapshot_name=`echo $snapshot_name | sed 's/ /-/g'`
                [ ! -z "$snapshot_name" ] && break
            done
 
            timestamp=`date +'%Y%m%d-%H%M'`
            cmd="aws redshift delete-cluster --cluster-identifier $cluster_choice --final-cluster-snapshot-identifier $snapshot_name-$timestamp"
 
            echo "About to execute the following command:"
            echo ""
            echo $cmd
            echo ""
 
            # confirm to continue
            check_confirmation
 
            echo "Creating snapshot: $snapshot_name-$timestamp.  Please wait.  This will take some time..."
            eval $cmd
            echo ""
            # display message again after json ouput
            echo "Creating snapshot: $snapshot_name-$timestamp.  Please wait.  This will take some time..."
 
            # check when snapshot creation is done.  Echo out running counter to show progress.
            count=0
            while [ 1 ]
            do
                aws redshift describe-cluster-snapshots --snapshot-identifier $snapshot_name-$timestamp | grep Status | grep available > /dev/null
 
                if [ $? -eq 0 ]
                then
                    break
                fi
                count=`expr $count + 1`
                printf "$count "
                sleep 2
            done
            echo ""
            echo "Snapshot $snapshot_name-$timestamp created."
            echo ""
 
            # show list of snapshots. It will now include new cluster.
            list_snapshots
            continue
            ;;
 
            ([q5])
            echo "Goodbye"
            break
            ;;
    esac
done