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DevOps-Bash-tools/hdfs_checksum_parallel.sh

82 lines
2.2 KiB
Bash

#!/usr/bin/env bash
# vim:ts=4:sts=4:sw=4:et
#
# Author: Hari Sekhon
# Date: 2019-11-27 16:09:34 +0000 (Wed, 27 Nov 2019)
#
# https://github.com/harisekhon/bash-tools
#
# License: see accompanying Hari Sekhon LICENSE file
#
# If you're using my code you're welcome to connect with me on LinkedIn and optionally send me feedback
#
# https://www.linkedin.com/in/harisekhon
#
set -euo pipefail
[ -n "${DEBUG:-}" ] && set -x
usage(){
cat <<EOF
Recurses HDFS path arguments outputting HDFS MD5-of-MD5 checksums for each file in parallel
since dfs command has slow startup
Calls HDFS command which is assumed to be in \$PATH
Capture stdout | sort > file.txt for comparisons
Make sure to kinit before running this if using a production Kerberized cluster
Setting environment variable SKIP_ZERO_BYTE_FILES to any value will skip files with zero bytes to save time since
they always return the same anyway: MD5-of-0MD5-of-0CRC32 00000000000000000000000070bc8f4b72a86921468bf8e8441dce5
Caveats:
This is slow because the HDFS command startup is slow and is called once per file path so doesn't scale well which
is why this launches several parallel dfs commands. Configure parallelism via environment variable PARALLELISM=N
where N must be an integer
If you want to skip zero byte files, set environment variable SKIP_ZERO_BYTE_FILES to any value
Tried this because Snakebite python library doesn't support checksum extraction
usage: ${0##*/} <file_or_directory_paths>
EOF
exit 3
}
if [[ "${1:-}" =~ ^- ]]; then
usage
fi
#PARALLELISM="${PARALELLISM:-$(grep -c '^processor[[:space:]]*:' /proc/cpuinfo)}"
# don't use all cores because if running on a datanode it might have dozens of cores and overwhelm namenode
# cap at 10 unless explicitly set
export PARALLELISM="${PARALELLISM:-10}"
if ! [[ "$PARALLELISM" =~ ^[[:digit:]]+$ ]]; then
echo "PARALLELISM must be set to an integer!"
exit 4
fi
skip_zero_byte_files(){
if [ -n "${SKIP_ZERO_BYTE_FILES:-}" ]; then
awk '{if($5 != 0) print }'
else
cat
fi
}
hdfs dfs -ls -R "$@" |
grep -v '^d' |
skip_zero_byte_files |
awk '{ $1=$2=$3=$4=$5=$6=$7=""; print }' |
#sed 's/^[[:space:]]*//' |
while read -r filepath; do
echo "hdfs dfs -checksum '$filepath'"
done |
parallel -j "$PARALLELISM"