#!/bin/bash
# unitc - a curl wrapper for configuring NGINX Unit
# https://github.com/nginx/unit/tree/master/tools
# NGINX, Inc. (c) 2022

# Defaults
#
ERROR_LOG=/dev/null
REMOTE=0
SHOW_LOG=1
NOLOG=0
QUIET=0
URI=""
SSH_CMD=""
METHOD=PUT
CONF_FILES=()

while [ $# -gt 0 ]; do
	OPTION=$(echo $1 | tr '[a-z]' '[A-Z]')
	case $OPTION in
		"-H" | "--HELP")
			shift
			;;

		"-L" | "--NOLOG" | "--NO-LOG")
			NOLOG=1
			shift
			;;

		"-Q" | "--QUIET")
			QUIET=1
			shift
			;;

		"GET" | "PUT" | "POST" | "DELETE" | "INSERT")
			METHOD=$OPTION
			shift
			;;

		"HEAD" | "PATCH" | "PURGE" | "OPTIONS")
			echo "${0##*/}: ERROR: Invalid HTTP method ($OPTION)"
			exit 1
			;;

		*)
			if [ -f $1 ] && [ -r $1 ]; then
				CONF_FILES+=($1)
			elif [ "${1:0:1}" = "/" ] || [ "${1:0:4}" = "http" ] && [ "$URI" = "" ]; then
				URI=$1
			elif [ "${1:0:6}" = "ssh://" ]; then
				UNIT_CTRL=$1
			else
				echo "${0##*/}: ERROR: Invalid option ($1)"
				exit 1
			fi
			shift
			;;
	esac
done

if [ "$URI" = "" ]; then
	cat << __EOF__
${0##*/} - a curl wrapper for managing NGINX Unit configuration

USAGE: ${0##*/} [options] URI

• URI is for Unit's control API target, e.g. /config
• A local Unit control socket is detected unless a remote one is specified.
• Configuration data is read from stdin.

General options
  filename …    # Read configuration data from files instead of stdin
  HTTP method   # Default=GET, or PUT with config data (case-insensitive)
  INSERT        # Virtual HTTP method to prepend data to an existing array
  -q | --quiet  # No output to stdout

Local options
  -l | --nolog  # Do not monitor the error log after applying config changes

Remote options
  ssh://[user@]remote_host[:port]/path/to/control.socket  # Remote Unix socket
  http://remote_host:port/URI                             # Remote TCP socket

 A remote Unit control socket may also be defined with the \$UNIT_CTRL
 environment variable as http://remote_host:port  -OR-  ssh://… (as above)

__EOF__
	exit 1
fi

# Figure out if we're running on the Unit host, or remotely
#
if [ "$UNIT_CTRL" = "" ]; then
	if [ "${URI:0:4}" = "http" ]; then
		REMOTE=1
		UNIT_CTRL=$(echo "$URI" | cut -f1-3 -d/)
		URI=/$(echo "$URI" | cut -f4- -d/)
	fi
elif [ "${UNIT_CTRL:0:6}" = "ssh://" ]; then
	REMOTE=1
	SSH_CMD="ssh $(echo $UNIT_CTRL | cut -f1-3 -d/)"
	UNIT_CTRL="--unix-socket /$(echo $UNIT_CTRL | cut -f4- -d/) _"
elif [ "${URI:0:1}" = "/" ]; then
	REMOTE=1
fi

if [ $REMOTE -eq 0 ]; then
	# Check if Unit is running, find the main process
	#
	PID=($(ps ax | grep unit:\ main | grep -v \ grep | awk '{print $1}'))
	if [ ${#PID[@]} -eq 0 ]; then
		echo "${0##*/}: ERROR: unitd not running (set \$UNIT_CTRL to configure a remote instance)"
		exit 1
	elif [ ${#PID[@]} -gt 1 ]; then
		echo "${0##*/}: ERROR: multiple unitd processes detected (${PID[@]})"
		exit 1
	fi

	# Read the significant unitd conifuration from cache file (or create it)
	#
	if [ -r /tmp/${0##*/}.$PID.env ]; then
		source /tmp/${0##*/}.$PID.env
	else
		# Check we have all the tools we will need (that we didn't already use)
		#
		MISSING=$(hash curl tr cut sed tail sleep 2>&1 | cut -f4 -d: | tr -d '\n')
		if [ "$MISSING" != "" ]; then
			echo "${0##*/}: ERROR: cannot find$MISSING: please install or add to \$PATH"
			exit 1
		fi

		# Get control address
		#
		PARAMS=$(ps $PID | grep unitd | cut -f2- -dv | tr '[]' ' ' | cut -f3- -d ' ' | sed -e 's/ --/\n--/g')
		CTRL_ADDR=$(echo "$PARAMS" | grep '\--control' | cut -f2 -d' ')
		if [ "$CTRL_ADDR" = "" ]; then
			CTRL_ADDR=$(`echo "$PARAMS" | grep unitd` --help | grep -A1 '\--control' | tail -1 |  cut -f2 -d\")
		fi

		# Prepare for network or Unix socket addressing
		#
		if [ $(echo $CTRL_ADDR | grep -c ^unix:) -eq 1 ]; then
			SOCK_FILE=$(echo $CTRL_ADDR | cut -f2- -d:)
			if [ -r $SOCK_FILE ]; then
				UNIT_CTRL="--unix-socket $SOCK_FILE _"
			else
				echo "${0##*/}: ERROR: cannot read unitd control socket: $SOCK_FILE"
				ls -l $SOCK_FILE
				exit 2
			fi
		else
			UNIT_CTRL="http://$CTRL_ADDR"
		fi

		# Get error log filename
		#
		ERROR_LOG=$(echo "$PARAMS" | grep '\--log' | cut -f2 -d' ')
		if [ "$ERROR_LOG" = "" ]; then
			ERROR_LOG=$(unitd --help | grep -A1 '\--log' | tail -1 | cut -f2 -d\")
		fi

		# Cache the discovery for this unit PID (and cleanup any old files)
		#
		rm -f /tmp/${0##*/}.* 2> /dev/null
		echo UNIT_CTRL=\"${UNIT_CTRL}\" > /tmp/${0##*/}.$PID.env
		echo ERROR_LOG=${ERROR_LOG} >> /tmp/${0##*/}.$PID.env
	fi
fi

# Choose presentation style
#
if [ $QUIET -eq 1 ]; then
	OUTPUT="head -c 0" # Equivalent to >/dev/null
elif hash jq 2> /dev/null; then
	OUTPUT="jq"
else
	OUTPUT="cat"
fi

# Get current length of error log before we make any changes
#
if [ -f $ERROR_LOG ] && [ -r $ERROR_LOG ]; then
	LOG_LEN=$(wc -l < $ERROR_LOG)
else
	NOLOG=1
fi

# Adjust HTTP method and curl params based on presence of stdin payload
#
if [ -t 0 ] && [ ${#CONF_FILES[@]} -eq 0 ]; then
	if [ "$METHOD" = "DELETE" ]; then
		$SSH_CMD curl -X $METHOD $UNIT_CTRL$URI 2> /tmp/${0##*/}.$$ | $OUTPUT
	else
		SHOW_LOG=$(echo $URI | grep -c ^/control/)
		$SSH_CMD curl $UNIT_CTRL$URI 2> /tmp/${0##*/}.$$ | $OUTPUT
	fi
else
	if [ "$METHOD" = "INSERT" ]; then
		if ! hash jq 2> /dev/null; then
			echo "${0##*/}: ERROR: jq(1) is required to use the INSERT method; install at <https://stedolan.github.io/jq/>"
			exit 1
		fi
		NEW_ELEMENT=$(cat ${CONF_FILES[@]})
		echo $NEW_ELEMENT | jq > /dev/null || exit $? # Test the input is valid JSON before proceeding
		OLD_ARRAY=$($SSH_CMD curl -s $UNIT_CTRL$URI)
		if [ "$(echo $OLD_ARRAY | jq -r type)" = "array" ]; then
			echo $OLD_ARRAY | jq ". |= [$NEW_ELEMENT] + ." | $SSH_CMD curl -X PUT --data-binary @- $UNIT_CTRL$URI 2> /tmp/${0##*/}.$$ | $OUTPUT
		else
			echo "${0##*/}: ERROR: the INSERT method expects an array"
			exit 3
		fi
	else
		cat ${CONF_FILES[@]} | $SSH_CMD curl -X $METHOD --data-binary @- $UNIT_CTRL$URI 2> /tmp/${0##*/}.$$ | $OUTPUT
	fi
fi

CURL_STATUS=${PIPESTATUS[0]}
if [ $CURL_STATUS -ne 0 ]; then
	echo "${0##*/}: ERROR: curl(1) exited with an error ($CURL_STATUS)"
	if [ $CURL_STATUS -eq 7 ] && [ $REMOTE -eq 0 ]; then
		echo "${0##*/}: Check that you have permission to access the Unit control socket, or try again with sudo(8)"
	else
		echo "${0##*/}: Trying to access $UNIT_CTRL$URI"
		cat /tmp/${0##*/}.$$ && rm -f /tmp/${0##*/}.$$
	fi
	exit 4
fi
rm -f /tmp/${0##*/}.$$ 2> /dev/null

if [ $SHOW_LOG -gt 0 ] && [ $NOLOG -eq 0 ] && [ $QUIET -eq 0 ]; then
	echo -n "${0##*/}: Waiting for log..."
	sleep $SHOW_LOG
	echo ""
	sed -n $((LOG_LEN+1)),\$p $ERROR_LOG
fi