generate_install_script.sh

#!/bin/bash

#################################################
# Copyright 2024 Massdriver, Inc                #
#                                               #
# This script generates a custom install script #
# to be ran on a source server to install the   #
# replication agent.                            #
#                                               #
#################################################

prompt_user() {
    local prompt="$1"
    local regex="$2"
    local error_message="$3"
    local result_var="$4"

    while true; do
        read -p "$prompt" input
        if [[ "$input" =~ $regex ]]; then
            eval "$result_var='$input'"
            break
        else
            echo "$error_message"
        fi
    done
}

prompt_user "Enter the AWS region (e.g., us-east-1): " \
    "^[a-z]{2}-[a-z]+-[0-9]+$" \
    "Error: Invalid AWS region format. Expected format is something like 'us-east-1'." \
    AWS_REGION

prompt_user "Enter the platform of the source server (Linux, Windows): " \
    "(Linux|linux|LINUX|Windows|windows|WINDOWS)" \
    "Error: Invalid platform. Expected 'Linux' or 'Windows'." \
    PLATFORM

prompt_user "Enter the source server name: " \
    "^[a-zA-Z0-9]{1}[a-zA-Z0-9-]+[a-zA-Z0-9]{1}$" \
    "Error: Server name cannot be blank and can contain letters, numbers, and hyphens. Cannot begin or end with hyphen." \
    SERVER_NAME

AWS_ACCOUNT_ID=$(aws sts get-caller-identity --query Account --output text)
ROLE_ARN="arn:aws:iam::$AWS_ACCOUNT_ID:role/AWSApplicationMigrationAgentInstallationRole"
ROLE_SESSION_NAME="massdriver-aws-mgn"

echo "Assuming role..."
ROLE_OUTPUT=$(aws sts assume-role \
    --role-arn "$ROLE_ARN" \
    --role-session-name "$ROLE_SESSION_NAME")
if [[ $? -ne 0 ]]; then
    echo "Error: Failed to assume role."
    exit 1
fi

AWS_ACCESS_KEY_ID=$(echo "$ROLE_OUTPUT" | jq -r '.Credentials.AccessKeyId')
AWS_SECRET_KEY=$(echo "$ROLE_OUTPUT" | jq -r '.Credentials.SecretAccessKey')
AWS_SESSION_TOKEN=$(echo "$ROLE_OUTPUT" | jq -r '.Credentials.SessionToken')
EXPIRATION=$(echo "$ROLE_OUTPUT" | jq -r '.Credentials.Expiration')

if [[ -z "$AWS_ACCESS_KEY_ID" || -z "$AWS_SECRET_KEY" || -z "$AWS_SESSION_TOKEN" ]]; then
  echo "Error: Failed to extract credentials."
  exit 1
fi

if [[ "$PLATFORM" =~ ^(linux|Linux|LINUX)$ ]]; then
    echo "Paste this bash command into the Linux source server to install the replication agent: "
    echo
    echo "curl -o install.sh https://raw.githubusercontent.com/massdriver-cloud/aws-mgn-scripts/refs/heads/main/install-agent-scripts/install_agent_linux.sh && bash install.sh "$AWS_ACCOUNT_ID" "$AWS_REGION" "$SERVER_NAME" "$AWS_ACCESS_KEY_ID" "$AWS_SECRET_KEY" "$AWS_SESSION_TOKEN""
    echo
    echo "Note: These credentials will expire in 1 hour ($EXPIRATION UTC). Ensure you complete the installation before this time."
fi

if [[ "$PLATFORM" =~ ^(windows|Windows|WINDOWS)$ ]]; then
    echo "Paste this PowerShell command into the Windows source server to install the replication agent: "
    echo
    echo "Invoke-WebRequest -Uri https://raw.githubusercontent.com/massdriver-cloud/aws-mgn-scripts/refs/heads/main/install-agent-scripts/install_agent_windows.ps1 -OutFile $env:TEMP\install_agent_windows.ps1; PowerShell -ExecutionPolicy Bypass -File $env:TEMP\install_agent_windows.ps1 -AWSAccountID $AWS_ACCOUNT_ID -AWSRegion $AWS_REGION -SourceServerName $SERVER_NAME -AWSAccessKeyID $AWS_ACCESS_KEY_ID -AWSSecretAccessKey $AWS_SECRET_KEY -AWSSessionToken $AWS_SESSION_TOKEN"
    echo
    echo "Note: These credentials will expire in 1 hour ($EXPIRATION UTC). Ensure you complete the installation before this time."
fi