Example pre-commit hook

pre-commit

#!/bin/sh

# Allows for colors and such
export TERM=xterm-256color


FILES="git diff --cached --name-only --diff-filter=ACM"
ROOT=$(git rev-parse --show-toplevel)
RETVAL=0

PYTHON_FILES=$($FILES | grep -E ".py$")
# This is because flake8's --exclude doesn't seem to work properly. Exclude via grep.
PYTHON_FILES_WITHOUT_MIGRATIONS=$($FILES | grep -E ".py$" | grep -v "migrations/")
JS_FILES=$($FILES | grep -E ".js$" | grep -v "dist" | grep -v "/build/")
COFFEE_FILES=$($FILES | grep -E ".coffee$" | grep -v "dist" | grep -v "/build/")

check_duplicates() {
    # Find all the files in the the project with a path like `.../migrations/(4 digits)...py`
    # Then it chops off everything after the last 4 digits, sorts and looks for unique counts
    # of every line i.e. `1   app1/migrations/0003`.
    # Then it greps for the lines which have exactly 1 copy of any migration path and number and removes them.
    # If anything else remains, it's a duplicate migration and we count the remaining items.
    dupes=$(find $ROOT -regex ".+migrations.[0-9][0-9][0-9][0-9].+py" \
        | egrep -o '(.+migrations/[0-9]{4})' \
        | sort | uniq -c | egrep -v " *1 .+")
    dupe_count=$(echo $dupes | grep -vE "^$" | wc -l)
    if [ $dupe_count -gt 0 ]; then
        printf "\033[31mDuplicate migration detected:\n\033[0m"
        printf "\033[33m$dupes\n\033[0m"
        return 1;
    fi
    return $RETVAL || 0;
}

if [ -n "$PYTHON_FILES" ]; then

    flake8=$(which flake8)
    has_flake8_print=$(flake8 --version | grep flake8-print | wc -l)
    has_flake8_debugger=$(flake8 --version | grep flake8-debugger | wc -l)

    if [ -z "$flake8" ] || [ $has_flake8_print -lt 1 ] || [ $has_flake8_debugger -lt 1 ]; then
        printf "\033[31mYou must install flake8 to check for python violations; sudo pip install flake8; sudo pip install flake8-print; sudo pip install flake8-debugger;\n\033[0m"
        RETVAL=1
    else
        printf "\033[32mChecking python files for flake8 violations\n\033[0m"

        for file in ${PYTHON_FILES_WITHOUT_MIGRATIONS}; do
            FLAKE8_ERRORS=$(git show :${file} | flake8 --ignore=E501 - | sed -e 's/^stdin\:/line /g')

            print_allowed=$(echo $file | grep -E "(management/commands|manage.py|/scripts|settings.py)" | wc -l)

            if [ "$print_allowed" -gt 0 ]; then
                FLAKE8_ERRORS=$(echo "$FLAKE8_ERRORS" | grep -v "print statement")
            fi

            if [ "$FLAKE8_ERRORS" != "" ]; then
                printf "\033[33mFlake8 errors detected in $file\n\033[0m"
                printf "\033[31m$FLAKE8_ERRORS\n\033[0m"
                RETVAL=1
            fi
        done
    fi

    # Check for duplicate migrations
    printf "\033[32mChecking Python files for duplicate migrations \n\033[0m"
    check_duplicates
    RETVAL=$?
fi

if [ -n "$JS_FILES" ]; then

    jshint=$(which jshint)
    node=$(which node)

    if [ -z "$jshint" ] || [ -z "$node" ]; then
        printf "\033[31mYou must install jshint to check for javascript violations; sudo npm install -g jshint\n\033[0m"
        RETVAL=1
    else
        printf "\033[32mChecking javascript files for linting errors\n\033[0m"

        for file in ${JS_FILES}; do
            result=$(git show :${file} | jshint - | sed -e 's/^stdin\: line/line/g')

            if [ "$result" != "" ]; then
                printf "\033[33mJSHint errors detected in $file\n\033[0m"
                printf "\033[31m$result\n\033[0m"
                RETVAL=1
            fi
        done
    fi
fi

if [ -n "$COFFEE_FILES" ]; then

    coffee_jshint=$(which coffee-jshint)
    node=$(which node)

    if [ -z "$coffee_jshint" ] || [ -z "$node" ]; then
        printf "\033[31mYou must install coffee-jshint to check for coffeescript violations; sudo npm install -g coffee-jshint\n\033[0m"
        RETVAL=1
    else
        printf "\033[32mChecking coffeescript files for linting errors\n\033[0m"

        for file in ${COFFEE_FILES}; do
            result=$(coffee-jshint -o browser --globals describe,it,angular,define,mixpanel,_,$,confirm,key  ${file} | tail -n +3 | sed -e 's/^/line /g')

            if [ "$result" != "" ]; then
                printf "\033[33mCoffee-JSHint errors detected in $file\n\033[0m"
                printf "\033[31m$result\n\033[0m"
                RETVAL=1
            fi
        done
    fi
fi

f [ -n "$JSON_FILES" ]; then
 
    jsonlint=$(which jsonlint)
 
    if [ -z "$jsonlint" ]; then
        printf "\033[31mYou must install jsonlint to check for json violations; sudo npm install -g jsonlint\n\033[0m"
        RETVAL=1
    else
        printf "\033[32mChecking json files for linting errors\n\033[0m"
 
        for file in ${JSON_FILES}; do
            result=$(jsonlint -q ${file})
            RESULT=$?
            if [ $RESULT -eq 1 ]
            then
                RETVAL=1
            fi
        done
    fi
fi

if [ $RETVAL -eq 0 ]; then
    printf "\033[32mNo errors found!\n\033[0m"
fi

exit $RETVAL