A Go Commit Hook for Less Future Headaches

pre-commit

#!/bin/bash
#
# Check a "few" things to help write more maintainable Go code.
# 
# OK, it's fairly comprehensive. So simply remove or comment out
# anything you don't want.
# 
# Don't forget to install (go get) each of these tools.
# More info at the URLs provided.
#
# This creates problems when something "fails" (like when you don't have any dependencies)
# despite it being ok to fail. So it's commented out for now, but you may want it for other purposes.
# set -e

RED='\033[0;31m'
LPURPLE='\033[1;35m'
DGRAY='\033[1;30m'
NC='\033[0m' # No Color

declare total_issues=0

# Golint (all files)
# https://github.com/golang/lint
declare lint_result=$(golint ./...)
if [[ $lint_result ]]; then
	lint_count=$(wc -l <<< "$lint_result")
	total_issues=$(($total_issues+$lint_count))

	# If there are a bunch of issues, change the color of the count.
	if [ $lint_count -gt 10 ]; then
		printf "${LPURPLE}Golint${RED} (${lint_count// })${NC}\n"
	else
		printf "${LPURPLE}Golint${NC} (${lint_count// })\n"
	fi
	# normal
	# printf "$lint_result"
	# dim the file path and line numbers
	echo "$lint_result" | GREP_COLOR='2;39' grep --color=always -E '^.+[0-9]\:*\s'
	printf "\n\n"
fi

# Dependency sanity check (replace the message about running with -v option to avoid confusion)
# https://github.com/divan/depscheck
# NOTE: This only checks dependencies in current directory (run from root)
declare depscheck_result=$(depscheck . | sed -e "s/Run with -v option to see detailed stats for dependencies.//g")
if [[ $depscheck_result ]]; then
	depscheck_count=$(echo "$depscheck_result" | grep -cE "good candidate")
	total_issues=$(($total_issues+$depscheck_count))

	# If there are a bunch of barely used dependencies, change the color of the count.
	if [ $depscheck_count -gt 5 ]; then
		printf "${LPURPLE}Depscheck${RED} (${depscheck_count// })${NC}\n"
	else
		printf "${LPURPLE}Depscheck${NC} (${depscheck_count// })\n"
	fi	
	printf "$depscheck_result\n\n"
fi

# Interfacer warns about the usage of types that are more specific than necessary.
# https://github.com/mvdan/interfacer
declare interface_lint_result=$(interfacer ./...)
if [[ $interface_lint_result ]]; then
	interface_lint_count=$(wc -l <<< "$interface_lint_result")
	total_issues=$(($total_issues+$interface_lint_count))

	# If there are a bunch of issues, change the color of the count.
	if [ $interface_lint_count -gt 5 ]; then
		printf "${LPURPLE}Interfacer${RED} (${interface_lint_count// })${NC}\n"
	else
		printf "${LPURPLE}Interfacer${NC} (${interface_lint_count// })\n"
	fi
	# normal
	# printf "$interface_lint_result"
	# dim the file path and line numbers
	echo "$interface_lint_result" | GREP_COLOR='2;39' grep --color=always -E '^.+[0-9]\:*\s'
	printf "\n\n"
fi

# structcheck warns about unused struct fields.
# https://github.com/opennota/check/
declare structcheck_result=$(structcheck ./...)
if [[ $structcheck_result ]]; then
	structcheck_count=$(wc -l <<< "$structcheck_result")
	total_issues=$(($total_issues+$structcheck_count))

	# If there are a bunch of issues, change the color of the count.
	if [ $structcheck_count -gt 5 ]; then
		printf "${LPURPLE}Unused struct fields${RED} (${structcheck_count// })${NC}\n"
	else
		printf "${LPURPLE}Unused struct fields${NC} (${structcheck_count// })\n"
	fi
	# normal
	# printf "$structcheck_result"
	# dim the file path and line numbers
	echo "$structcheck_result" | GREP_COLOR='2;39' grep --color=always -E '^.+[0-9]\:*\s'
	printf "\n\n"
fi

# varcheck warns about unused global variables and constants.
# https://github.com/opennota/check/
declare varcheck_result=$(varcheck ./...)
if [[ $varcheck_result ]]; then
	varcheck_count=$(wc -l <<< "$varcheck_result")
	total_issues=$(($total_issues+$varcheck_count))

	# If there are a bunch of issues, change the color of the count.
	if [ $varcheck_count -gt 3 ]; then
		printf "${LPURPLE}Unused variables and constants${RED} (${varcheck_count// })${NC}\n"
	else
		printf "${LPURPLE}Unused variables and constants${NC} (${varcheck_count// })\n"
	fi
	# normal
	# printf "$varcheck_result"
	# dim the file path and line numbers
	echo "$varcheck_result" | GREP_COLOR='2;39' grep --color=always -E '^.+[0-9]\:*\s'
	printf "\n\n"
fi

# errcheck warns about unchecked errors in your code.
# https://github.com/kisielk/errcheck
declare errcheck_result=$(errcheck ./...)
if [[ $errcheck_result ]]; then
	errcheck_count=$(wc -l <<< "$errcheck_result")
	total_issues=$(($total_issues+$errcheck_count))
	printf "${LPURPLE}Unchecked errors${NC} (${errcheck_count// })\n"
	# normal
	# printf "$errcheck_result"
	# dim the file path and line numbers
	echo "$errcheck_result" | GREP_COLOR='2;39' grep --color=always -E '^.+[0-9]\:*\s'
	printf "\n\n"
fi

# gocyclo reports cyclomatic complexity.
# https://github.com/fzipp/gocyclo
cyclo_tolerance=10
declare cyclo_result=$(gocyclo -over "$cyclo_tolerance" .)
if [[ $cyclo_result ]]; then
	cyclo_count=$(wc -l <<< "$cyclo_result")
	total_issues=$(($total_issues+$cyclo_count))
	printf "${LPURPLE}Cyclomatic complexity above ${cyclo_tolerance}${NC} (${cyclo_count// })\n"
	printf "$cyclo_result\n\n"
fi

# NOTE: This returns a count of 1 if it doesn't find any SQL commands.
# Only enable if you have SQL commands. Or discount a line like:
# Did not find any commands (i.e., main functions).
#
# safesql looks for SQL injection vulnerabilities in your code.
# https://github.com/stripe/safesql
# declare sqlcheck_result=$(safesql -q .)
# if [[ $sqlcheck_result ]]; then
#	sqlcheck_count=$(wc -l <<< "$sqlcheck_result")
#	total_issues=$(($total_issues+$sqlcheck_count))
#	# Always red, not good to have any.
#	printf "${LPURPLE}SQL injection warning${RED} (${sqlcheck_count// })${NC}\n"
#	# normal
#	# printf "$sqlcheck_result"
#	echo "$sqlcheck_result" | GREP_COLOR='2;39' grep --color=always -E '^.+[0-9]\:*\s'
#	printf "\n\n"
# fi


# If there were issues, exit 1
if [ $total_issues -gt 0 ]; then
	# There were some issues that might need attention
	exit 1
fi

exit 0

Make sure you have all of the necessary tools before running this! The tools can be found at the URLs in the comments. Also note that a few style choices with regard to color have been made. Easily adjustable things.

If you're like me and want to write better Go code, these are the tools I've found really helpful (I wrote an article about it on Medium if you like reading). More may be added over time, please feel free to share your favorites in the comments below.

Full disclosure: I am not a bash scripting master - it is entirely possible that there were more clever ninja ways to write some things.

Note: I've realized that some of the checks here will return messages despite not having anything to fix. So counting line output needs to be adjusted to ignore certain phrases. Of course you can still run this script manually, but it likely won't work great for a pre-commit hook as is...Unless your code doesn't trigger some of the messages (which is possible, though unlikely for a brand new project).