Semantic commit message hook for git in bash

commit-msg

#!/bin/bash
# ISC License
#
# Copyright (c) 2019-present, Mykhailo Stadnyk <mikhus@gmail.com>
#
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
input_file=$1
first_line=`head -n1 ${input_file}`
allowed="feat|fix|docs|style|refactor|perf|test|chore"
pattern="^(${allowed}):( (\[[-A-Za-z0-9]+\]))? (.+)$"

red='\033[1;31m'
gre='\033[1;32m'
yel='\033[1;33m'
cya='\033[1;36m'
def='\033[0m'

trim() {
    local s="$*"
    s="${s#"${s%%[![:space:]]*}"}"
    s="${s%"${s##*[![:space:]]}"}"
    echo -n "$s"
}

usage () {
    echo -e "${red}Bad commit message!${def}"
    echo -e "Correct format is: ${cya}tag: [BUG_ID] Message${def}"
    echo -e "Allowed tags:"

    IFS="|" read -ra items <<< ${allowed}
    for item in "${items[@]}"; do
        echo -e " - ${gre}${item}${def}"
    done

    echo -e "[JIRA_ID] is optional, but recommended."
    echo -e "Message can not be empty!"
}

if ! [[ ${first_line} =~ ${pattern} ]]; then
    # bad commit message format overall, so
    usage ; exit 1
fi

msg=$(trim "${BASH_REMATCH[4]}")
bug_id=$(trim "${BASH_REMATCH[3]}")

if [[ ${msg} = "" ]]; then
    # empty commit message when trimmed
    usage ; exit 1
fi

if [[ ${bug_id} = "" ]]; then
    # jira id not found - accept, but warn
    echo -e "${red}Warning:${yel} bug-tracking identifier is missing...${def}"
fi

This will allow to commit only if commit message provided satisfies to so called "semantic release"
So it will expect the following message format:

tag: [JIRA_ID] Message

Where tag should be one of feat|fix|docs|style|refactor|perf|test|chore
[BUG_ID] is optional and will generate warning message if missing
Commit message itself is checked to be non-empty message