#!/bin/bash

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

# Before running updates, the replication needs to be set up with the timestamp
# set to the day of the latest planet dump. Setting to midnight ensures we get
# conistent data after first run. osmosis --read-replication-interval-init is
# used to initially create the state file

# Define exit handler
function onexit {
    [ -f sequence-prev.txt ] && mv sequence-prev.txt sequence.txt
}

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

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

# Install exit handler
trap onexit EXIT

# Loop indefinitely
while true
do
    # Work out the name of the next file
    file="changes-$(cat sequence.txt).osc.gz"

    # Save sequence file so we can rollback if an error occurs
    cp sequence.txt sequence-prev.txt

    # Fetch the next set of changes
    pyosmium-get-changes --sequence-file=sequence.txt --outfile=${file}

    # Save exit status
    status=$?

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

        # Log the new data
        echo "Fetched new data from $(cat sequence-prev.txt) to $(cat sequence.txt) into ${file}"

        # Apply the changes to the database
        osm2pgsql --database gis --slim --append --number-processes=1 \
<% if node[:tile][:node_file] -%>
                  --flat-nodes=<%= node[:tile][:node_file] %> \
<% end -%>
<% if node[:tile][:styles][:default][:revision] >= "v4.0.0" -%>
                  --multi-geometry --hstore \
                  --style=/srv/tile.openstreetmap.org/styles/default/openstreetmap-carto.style \
                  --tag-transform-script=/srv/tile.openstreetmap.org/styles/default/openstreetmap-carto.lua \
<% end -%>
                  ${file}

        # No need to rollback now
        rm sequence-prev.txt

        # Get buffer count
        buffers=$(osmium fileinfo --extended --get=data.buffers.count ${file})

        # If this diff has content mark it as the latest diff
        if [ $buffers -gt 0 ]
        then
            ln -f ${file} changes-latest.osc.gz
        fi

        # Queue these changes for expiry processing
        ln ${file} expire-queue/${file}

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

        # Disable exit on error
        set +e
    elif [ $status -eq 3 ]
    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 our failure to fetch changes
        echo "Failed to fetch changes - waiting a few minutes before retry"

        # Remove any output that was produced
        rm -f ${file}

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