persistent-sshfs

#!/bin/bash

# Check if a file path is provided as an argument
if [ "$#" -ne 1 ]; then
    echo "Usage: $0 <mountpoints_file>"
    exit 1
fi

mountpoints_file="$1"

# Check if the file exists
if [ ! -f "$mountpoints_file" ]; then
    echo "File not found: $mountpoints_file"
    exit 1
fi

# Initialize an empty mounts array
declare -a mounts=()

# Read mount points from the file and add them to the mounts array
while IFS= read -r line; do
    mounts+=("$line")
done <"$mountpoints_file"

# Define log levels
LOG_LEVEL_DEBUG="DEBUG"
LOG_LEVEL_INFO="INFO"
LOG_LEVEL_ERROR="ERROR"

# Default log level
LOG_LEVEL_DEFAULT="$LOG_LEVEL_INFO"

# Get the log level from the environment variable or use default
LOG_LEVEL="${LOG_LEVEL:-$LOG_LEVEL_DEFAULT}"

# Convert log levels to integers for comparison
log_level_to_int() {
    case "$1" in
    "$LOG_LEVEL_DEBUG") echo 3 ;;
    "$LOG_LEVEL_INFO") echo 2 ;;
    "$LOG_LEVEL_ERROR") echo 1 ;;
    *) echo 0 ;;
    esac
}

LOG_LEVEL_INT=$(log_level_to_int "$LOG_LEVEL")

log() {
    local level="$1"
    local message="$2"

    local level_int
    level_int="$(log_level_to_int "$level")"

    if [ "$level_int" -le "$LOG_LEVEL_INT" ]; then
        echo "$(date '+%Y-%m-%d %H:%M:%S') [$level] $message"
    fi
}

log "$LOG_LEVEL_INFO" "Starting with mount points from $mountpoints_file and LOG_LEVEL=$LOG_LEVEL"

# Array to keep track of background process PIDs
declare -a pids=()

# Clean up function to unmount all mount points and kill background processes
cleanup() {
    log "$LOG_LEVEL_INFO" "Cleanup: unmounting all SSHFS mounts and exiting..."

    # Kill background processes
    for pid in "${pids[@]}"; do
        if kill -0 "$pid" 2>/dev/null; then
            log "$LOG_LEVEL_INFO" "Stopping background process $pid"

            kill "$pid"
        fi
    done

    # Unmount all SSHFS mounts
    for mount_info in "${mounts[@]}"; do
        IFS=':' read -r -a array <<<"$mount_info"
        mount_point="${array[0]}"
        if mount | grep -q "on $mount_point type fuse.sshfs"; then
            fusermount -u "$mount_point" && log "$LOG_LEVEL_INFO" "Unmounted $mount_point"
        fi
    done
}

# Check SSH key-based authentication
check_ssh_key_auth() {
    local userhost="$1"
    local port="$2"

    # Attempt to execute a non-interactive command (`exit`) on the remote server using the specified port
    while ! ssh -o BatchMode=yes -o PasswordAuthentication=no -p "$port" "$userhost" exit; do
        log "$LOG_LEVEL_ERROR" "SSH key-based authentication to $userhost on port $port failed or requires a password, retrying in 10 seconds..."
        sleep 10
    done

    log "$LOG_LEVEL_INFO" "SSH key-based authentication to $userhost on port $port successful."
}

# Trap SIGINT and SIGTERM
trap cleanup SIGINT SIGTERM

# Iterate over each mount point and handle in the background
for mount in "${mounts[@]}"; do
    # Parse the mount string to extract variables
    IFS=':' read -r mountpoint userhost port remotedir <<<"$(echo "$mount" | sed -E 's/(.*):(.*@.*):([0-9]+):(.*)/\1:\2:\3:\4/')"

    log "$LOG_LEVEL_INFO" "Processing mount: $mountpoint"

    # Ensure the local directory exists
    if [ ! -d "$mountpoint" ]; then
        log "$LOG_LEVEL_INFO" "$mountpoint does not exist, creating..."
        mkdir -p "$mountpoint"
    fi

    # Launch a background process for each mount
    (
        # Check SSH key-based authentication using userhost and port
        check_ssh_key_auth "$userhost" "$port"

        # Attempt to mount, keep retrying if it fails
        while true; do
            if mount | grep -q "on $mountpoint type fuse.sshfs"; then
                log "$LOG_LEVEL_DEBUG" "$mountpoint is already mounted."
                break # Exit the loop if the mount is successful
            else
                log "$LOG_LEVEL_INFO" "Attempting to mount $mountpoint..."
                if sshfs -o reconnect -o port="$port" "$userhost:$remotedir" "$mountpoint"; then
                    log "$LOG_LEVEL_INFO" "$mountpoint mounted successfully."
                    break # Exit the loop if the mount is successful
                else
                    log "$LOG_LEVEL_ERROR" "Failed to mount $mountpoint on port $port, retrying in 10 seconds..."
                fi
            fi
            sleep 10
        done
    ) &
    # Store the PID of the background process
    pids+=("$!")
done

# Wait for all background processes to complete
for pid in "${pids[@]}"; do
    log "$LOG_LEVEL_DEBUG" "Waiting for background process $pid to complete..."
    wait "$pid"
done