#!/bin/bash

# DO NOT EDIT - This file is being maintained by Chef

# Initialize timestamp with day of latest planet dump
# Setting to midnight ensures we get conistent data after first run
# osmosis --read-replication-interval-init

# Send output to the log
exec > /var/log/replicate/replicate.log 2>&1

# Change to the replication state directory
cd /var/lib/replicate

# Read in initial state
. state.txt

# Loop indefinitely
while true
do
    # Work out the name of the next file
    file="changes-${sequenceNumber}.osm.gz"

    # Fetch the next set of changes
    osmosis --read-replication-interval --simc --write-xml-change file="${file}" compressionMethod="gzip"

    # Check for errors
    if [ $? -eq 0 ]
    then
        # Enable exit on error
	set -e

        # Remember the previous sequence number
	prevSequenceNumber=$sequenceNumber

        # Read in new state
	. state.txt

        # Did we get any new data?
	if [ "${sequenceNumber}" == "${prevSequenceNumber}" ]
        then
            # Log the lack of data
	    echo "No new data available. Sleeping..."

	    # Remove file, it will just be an empty changeset
	    rm ${file}

            # Sleep for a short while
	    sleep 30
	else
            # Log the new data
	    echo "Fetched new data from ${prevSequenceNumber} to ${sequenceNumber} into ${file}"

            # Apply the changes to the database
<% if node[:tile][:node_file] -%>
            osm2pgsql --slim --append --flat-nodes=<%= node[:tile][:node_file] %> ${file}
<% else -%>
            osm2pgsql --slim --append ${file}
<% end -%>

            # Expire tiles which are touched by the changes
            /usr/local/bin/expire-tiles ${file} > /dev/null 2>&1 &
	fi

        # Delete old downloads
	find . -name 'changes-*.gz' -mmin +300 -exec rm -f {} \;

        # Disable exit on error
        set +e
    else
        # Log our failure to fetch changes
	echo "Failed to fetch changes - waiting a few minutes before retry"

        # Wait five minutes and have another go
	sleep 300
    fi
done