belarus-2020-2021/scripts/get-bridge-data.sh

#!/bin/bash

# Populate array of months we care about
months=()
# 2020
for i in $(seq 7 12); do
    months+=( 2020-$(printf %02d $i) )
done
# 2021
for i in $(seq 1 4); do
    months+=( 2021-$(printf %02d $i) )
done

# Download the archives if we don't have them already
for i in ${months[@]}; do
    if [ ! -f data/bridge-extra-infos-${i}.tar.xz ]; then
        curl -Lo data/bridge-extra-infos-${i}.tar.xz https://collector.torproject.org/archive/bridge-descriptors/extra-infos/bridge-extra-infos-${i}.tar.xz || exit 1
    fi
done

# Check that we have the right archives
sha256sum -c data/bridge-extra-infos.sha256 || exit 1

# If we haven't already extracted the bridge data, then do so. This will
# take a long time (around 12.5 hours on my device) because it needs to
# process around 3 million small files, and it will require a few GB of
# free space while running. In the end, this results in about 91 MB of
# bridge data that we care about.
if [ ! -d data/bridge_data ]; then

    cd data

    mkdir bridge_data

    # This is around 20 GB of data uncompressed, so don't extract it all
    # at once. Instead, extract and process one month at a time.
    for i in ${months[@]}; do
        if [ ! -d bridge-extra-infos-${i} ]; then
            echo "Extracting bridge-extras-infos-${i}.tar.xz"
            tar xf bridge-extra-infos-${i}.tar.xz || exit 1
        fi

        echo "Processing bridge-extra-infos-${i}"
        for j in bridge-extra-infos-${i}/*; do
            for k in ${j}/*; do
                for l in ${k}/*; do
                    if [[ -s "${k}" ]]; then
                        fingerprint=$(grep -Po '(?<=^extra-info )(.*)(?=$)' "${l}" | grep -Po '(?<= )(.*)(?=$)')
                        date=$(grep -Po '(?<=^published )(.*)(?= )' "${l}")
                        # Convert to Julian date, thanks to
                        # https://stackoverflow.com/a/43318209
                        date_julian=$(( $(date +%s -d "${date}") / 86400 + 2440587 ))
                        count=$(grep -Po '(?<=^bridge-ips )(.*)(?=$)' "${l}" | grep -Po '(?<=by=)(.*?)(?=(,|$))')
                        if [ -z "$count" ]; then
                            count=0
                        fi

                        if [[ -n "${date_julian}" && -n "${fingerprint}" ]]; then
                            echo "${date_julian},${count}" >> bridge_data/${fingerprint}
                        else
                            echo "Error for ${l}"
                            echo "    fingerprint: ${fingerprint}"
                            echo "    date:        ${date_julian}"
                            echo "    count:       ${count}"
                        fi
                    fi
                done
            done
        done

        echo "Removing bridge-extra-infos-${i} directory to free up space"
        rm -r bridge-extra-infos-${i}
    done

    cd ..
fi