#!/usr/bin/env bash
# vim:ts=4:sts=4:sw=4:et
#
# Author: Hari Sekhon
# Date: 2019-12-10 11:33:52 +0000 (Tue, 10 Dec 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 to help steer this or other code I publish
#
# https://www.linkedin.com/in/harisekhon
#
# Script to more easily connect to Impala without having to find an impalad and repeatedly specify options like -k for kerberos
#
# Tested on Impala 2.7.0, 2.12.0 on CDH 5.10, 5.16 with Kerberos and SSL
#
# If using dedicated coordinators then consider setting IMPALA_HOST to one of those explicitly, see
#
# https://docs.cloudera.com/documentation/enterprise/5-16-x/topics/impala_dedicated_coordinator.html
#
# See also:
#
# find_active_impalad.py - https://github.com/harisekhon/devops-python-tools
#
# HAProxy Configs for Impala and many other technologies - https://github.com/harisekhon/haproxy-configs
#
# If you get an error such as:
#
# Error connecting: TTransportException, TSocket read 0 bytes
#
# then check if you need to add --ssl to the command line (or export IMPALA_SSL=1 to do this automatically, eg. put in .bashrc or similar)
# useful options for scripting:
#
# -q --query
# -B --delimited
# --output_delimiter=\t # default
# --quiet
#
# See adjacent impala_*.sh scripts for slightly better versions of these quick command line examples, including better escaping
#
# list all databases:
#
# ./impala_shell.sh -Bq 'show databases' | awk '{print $1}'
#
# list all tables in all databases:
#
# ./impala_shell.sh -Bq 'show databases' | while read db rest; do ./impala_shell.sh -Bq "use $db; show tables" | sed "s/^/$db./"; done
#
# row counts for all tables in all databases:
#
# ./impala_shell.sh --quiet -Bq 'show databases' | while read db rest; do ./impala_shell.sh --quiet -Bq "use $db; show tables" | while read table; do printf "%s\t" "$db.$table"; ./impala_shell.sh --quiet -Bq "use $db; SELECT COUNT(*) FROM $table"; done; done > row_counts.tsv
set -euo pipefail
[ -n " ${ DEBUG :- } " ] && set -x
opts = " ${ IMPALA_OPTS :- } "
core_site_xml = " ${ HADOOP_CORE_SITE_XML :- /etc/hadoop/conf/core-site.xml } "
#if ! [ -f "$core_site_xml" ]; then
# echo "File not found: $core_site_xml. Did you run this on a Hadoop node?" >&2
# exit 1
#fi
if [ -n " ${ IMPALA_KERBEROS :- } " ] ||
grep -A 1 hadoop.security.authentication " $core_site_xml " 2>/dev/null | grep -q kerberos; then
opts = " $opts -k "
fi
if [ -n " ${ IMPALA_SSL :- } " ] ; then
opts = " $opts --ssl "
fi
topology_map = " ${ HADOOP_TOPOLOGY_MAP :- /etc/hadoop/conf/topology.map } "
if [ -n " ${ IMPALA_HOST :- } " ] ; then
impalad = " $IMPALA_HOST "
elif [ -f " $topology_map " ] ; then
#echo "picking random impala from hadoop topology map" >&2
# nodes in the topology map that aren't masters, namenodes, controlnodes etc probably have impalad running on them, so pick one at random to connect to
# or alternatively use HAProxy config for load balanced impala clusters - see https://github.com/harisekhon/haproxy-configs
impalad = " $(
awk -F'"' '/<node name="[A-Za-z]/{print $2}' " $topology_map " |
grep -Ev '^[^.]*(name|master|control)' |
shuf -n 1
) "
else
impalad = " $( hostname -f) "
#echo "IMPALA_HOST not set and topology map '$topology_map' not found, defaulting to local host $impalad"
fi
# split opts
# shellcheck disable=SC2086
exec impala-shell $opts -i " $impalad " " $@ "