Initial support for dark mode terminals (#933)

packages.txt

@@ -4,6 +4,8 @@ aws-iam-authenticator@cloudposse
 bash
 bash-completion
 bats@community
+# bc is for doing floating point math in the shell
+bc
 # no arm64 cfssl@cloudposse
 coreutils
 chamber@cloudposse

rootfs/etc/codefresh/require_vars

@@ -61,11 +61,11 @@ function require_cfvars() {
 }
 
 function red() {
-	echo "$(tput setaf 1)$*$(tput sgr0)"
+	echo "$(tput setaf 1)$*$(tput op)"
 }
 
 function yellow() {
-	echo "$(tput setaf 3)$*$(tput sgr0)"
+	echo "$(tput setaf 3)$*$(tput op)"
 }
 
 echo "REQUIRE VARS: checking for presence of required variables"

rootfs/etc/profile.d/_07-term-mode.sh

@@ -0,0 +1,147 @@
+#!/bin/bash
+# Files in the profile.d directory are executed by the lexicographical order of their file names.
+# This file is named _07-term-mode.sh. The leading underscore is needed to ensure this file executes before
+# other files that depend on the functions defined here. The number portion is to ensure proper ordering among
+# the high-priority scripts.
+#
+# This file has no dependencies and should come first.
+
+# This function determines if the terminal is in dark mode.
+
+# For now, we use OSC sequences to query the terminal's foreground and background colors.
+# See https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h3-Operating-System-Commands
+# Adapted from https://bugzilla.gnome.org/show_bug.cgi?id=733423#c2
+#
+# At some point we may introduce other methods to determine the terminal's color scheme.
+
+# Normally this function produces no output, but with -b, it outputs "true" or "false",
+# with -bb it outputs "true", "false", or "unknown". (Otherwise, unknown assume light mode.)
+# and always returns true. With -l it outputs integer luminance values for foreground
+# and background colors. With -ll it outputs labels on the luminance values as well.
+function _is_term_dark_mode() {
+	local x fg_rgb bg_rgb fg_lum bg_lum
+
+	# Extract the RGB values of the foreground and background colors via OSC 10 and 11.
+	# Redirect output to `/dev/tty` in case we are in a subshell where output is a pipe,
+	# because this output has to go directly to the terminal.
+	stty -echo
+	echo -ne '\e]10;?\a\e]11;?\a' >/dev/tty
+	IFS=: read -t 0.1 -d $'\a' x fg_rgb
+	IFS=: read -t 0.1 -d $'\a' x bg_rgb
+	stty echo
+
+	if [[ -z $fg_rgb ]] || [[ -z $bg_rgb ]]; then
+		if [[ $GEODESIC_TRACE =~ "terminal" ]]; then
+			echo $(tput setaf 1)* TRACE: "Terminal did not respond to OSC 10 and 11 queries.$(tput sgr0)" >&2
+		fi
+		# If we cannot determine the color scheme, we assume light mode for historical reasons.
+		if [[ "$*" =~ -b ]]; then
+			if [[ "$*" =~ -bb ]]; then
+				echo "unknown"
+			else
+				echo "false"
+			fi
+			return 0 # when returning text, always return success
+		fi
+		return 1 # Assume light mode
+	fi
+
+	if [[ "${x#*;}" != "rgb" ]]; then
+		# Always output this error, because we want to hear about
+		# other color formats users want us to support.
+		echo "$(tput set bold)($tput setaf 1)Terminal reported unknown color format: ${x#*;}$(tput sgr0)" >&2
+		return 1
+	fi
+
+	# Convert the RGB values to luminance by summing the values.
+	fg_lum=$(_srgb_to_luminance "$fg_rgb")
+	bg_lum=$(_srgb_to_luminance "$bg_rgb")
+	if [[ "$*" =~ -l ]]; then
+		if [[ "$*" =~ -ll ]]; then
+			echo "Foreground luminance: $fg_lum, Background luminance: $bg_lum"
+		else
+			echo "$fg_lum $bg_lum"
+		fi
+	fi
+	# If the background luminance is less than the foreground luminance, we are in dark mode.
+	if ((bg_lum < fg_lum)); then
+		if [[ "$*" =~ -b ]]; then
+			echo "true"
+		fi
+		return 0
+	fi
+	# If we cannot determine the color scheme, we assume light mode for historical reasons.
+	if [[ "$*" =~ -b ]]; then
+		echo "false"
+		return 0 # when returning text, always return success
+	fi
+	return 1
+}
+
+# Converting RGB to luminance is a lot more complex than summing the values.
+# To begin with, you need to know the color space, and if it is not a standard
+# one, then you need a full color profile. To start with, we assume sRGB,
+# and perhaps can add more color spaces later.
+#
+# Note: if we just take the simple sum of RGB values, we get in trouble with
+# blue backgrounds and foregrounds, which can have very high hex values but still be dark.
+#
+# To complicate matters, WCAG originally published the wrong formula for
+# converting sRGB to luminance.  The sRGB space has a linear region, and the switch
+# from linear to exponential should be 0.04045, not 0.03928.
+# See https://www.w3.org/TR/WCAG21/#dfn-relative-luminance
+#
+# Unfortunately, many online calculators use the wrong formula, which you can test
+# by checking the luminance for #0a570a571010, which should be .0032746029, not .003274534
+# However, there is no difference for 8-bit colors and, as you can see, for 16 bit colors,
+# the difference is negligible.
+#
+# You can use ImageMagick's `convert` command to convert an sRGB color to luminance:
+#   convert xc:<color> -intensity Rec709Luminance  -format "%[fx:intensity]" info:
+# For #0a570a571010, this will output 0.00327457, which is slightly off, likely
+# due to internal rounding.
+#
+function _srgb_to_luminance() {
+	local color="$1"
+	local red green blue
+
+	if [[ -z $color ]]; then
+		if [[ $GEODESIC_TRACE =~ "terminal" ]]; then
+			# Use tput and sgr0 here because this is early in the startup sequence and trace logging
+			echo "$(tput setaf 1)* TRACE: ${FUNCNAME[0]} called with empty or no argument.$(tput sgr0)" >&2
+		fi
+		echo "0"
+		return
+	fi
+
+	# Split the color string into red, green, and blue components
+	IFS='/' read -r red green blue <<<"$color"
+
+	# Normalize hexadecimal values to [0,1] and linearize them
+	normalize_and_linearize() {
+		local hex=${1^^} # Uppercase the hex value, because bc requires it
+		local float=$(echo "ibase=16; $hex" | bc)
+		local max=$(echo "ibase=16; 1$(printf '%0*d' ${#hex} 0)" | bc) # Accommodate the number of digits
+		local normalized=$(echo "scale=10; $float / ($max - 1)" | bc)
+
+		# Apply gamma correction
+		if (($(echo "$normalized <= 0.04045" | bc))); then
+			echo "scale=10; $normalized / 12.92" | bc
+		else
+			echo "scale=20; e(l(($normalized + 0.055) / 1.055) * 2.4)" | bc -l
+		fi
+	}
+
+	# Linearize each color component
+	local R=$(normalize_and_linearize $red)
+	local G=$(normalize_and_linearize $green)
+	local B=$(normalize_and_linearize $blue)
+
+	# Calculate luminance
+	local luminance=$(echo "scale=10; 0.2126 * $R + 0.7152 * $G + 0.0722 * $B" | bc)
+
+	# Luminance is on a scale of 0 to 1, but we want to be able to
+	# compare integers in bash, so we multiply by a big enough value
+	# to get an integer and maintain precision.
+	echo "scale=0; ($(echo "scale=10; $luminance * 1000000000" | bc) + 0.5) / 1" | bc
+}

rootfs/etc/profile.d/_10-colors.sh

@@ -1,37 +1,152 @@
 # Files in the profile.d directory are executed by the lexicographical order of their file names.
 # This file is named _10-colors.sh. The leading underscore is needed to ensure this file executes before
 # other files that depend on the functions defined here. The number portion is to ensure proper ordering among
-# the high-priority scripts
-# This file has no dependencies and should come first.
-function red() {
-	echo "$(tput setaf 1)$*$(tput setaf 0)"
+# the high-priority scripts.
+#
+# This file depends on _07-term-mode.sh and should come second.
+
+# This file provides functions to colorize text in the terminal.
+# It has moderate support for light and dark mode, but it is not perfect.
+# The main change is that it uses the terminal's default colors for foreground and background,
+# whereas the previous version "reset" the color by setting it to black, which fails in dark mode.
+
+function update_terminal_mode() {
+	local dark_mode=$(_is_term_dark_mode -b)
+	if [[ ! -v _geodesic_tput_cache ]] || [[ "${_geodesic_tput_cache[dark_mode]}" != "$dark_mode" ]]; then
+		_geodesic_tput_cache_init
+	else
+		local mode="light"
+		if [[ $dark_mode == "true" ]]; then
+			mode="dark"
+		fi
+		echo "Not updating terminal mode from $mode to $mode"
+	fi
 }
 
-function green() {
-	echo "$(tput setaf 2)$*$(tput setaf 0)"
+# We call `tput` several times for every prompt, and it can add up, so we cache the results.
+function _geodesic_tput_cache_init() {
+	declare -g -A _geodesic_tput_cache
+
+	local color_off=$(tput op) # reset foreground and background colors to defaults
+	local bold=$(tput bold)
+	local bold_off
+
+	if [[ -n "$bold" ]]; then
+		# Turning on bold is a standard `tput` attribute, but turning it off is not.
+		# However, turning off bold is an ECMA standard (SGR 22), so it is not
+		# unreasonable for us to use it. If it causes problems, people can set
+		#   export TERM_BOLD_OFF=$(tput sgr0)
+		# http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf
+		bold_off=${TERM_BOLD_OFF:-$'\033[22m'}
+	fi
+
+	# Set up normal colors for light mode
+	_geodesic_tput_cache=(
+		[black]=$(tput setaf 0)
+		[red]=$(tput setaf 1)
+		[green]=$(tput setaf 2)
+		[yellow]=$(tput setaf 3)
+		[blue]=$(tput setaf 4)
+		[magenta]=$(tput setaf 5)
+		[cyan]=$(tput setaf 6)
+		[white]=$(tput setaf 7)
+	)
+
+	if _is_term_dark_mode; then
+		_geodesic_tput_cache[black]=$(tput setaf 7)              # swap black and white
+		_geodesic_tput_cache[white]=$(tput setaf 0)              # 0 is ANSI black, 7 is ANSI white
+		_geodesic_tput_cache[blue]=${_geodesic_tput_cache[cyan]} # blue is too dark, use cyan instead
+	else
+		_geodesic_tput_cache[yellow]=${_geodesic_tput_cache[magenta]} # yellow is too light, use magenta instead
+	fi
+
+	local key
+	for key in "${!_geodesic_tput_cache[@]}"; do
+		if [[ -n ${_geodesic_tput_cache["$key"]} ]]; then
+			# Note, we cannot use printf for "-off" because command substitution strips trailing newlines
+			_geodesic_tput_cache["${key}-off"]="$color_off"$'\n'
+			_geodesic_tput_cache["bold-${key}"]=$(printf "%s%s" "$bold" "${_geodesic_tput_cache["$key"]}")
+			_geodesic_tput_cache["bold-${key}-off"]="${color_off}${bold_off}"$'\n'
+
+			# Note $'\x01' and $'\x02' are ASCII codes to put around non-printing characters so that
+			# bash can correctly calculate the visible length of the string.
+			# They are equivalent to \[ and \] in a bash prompt string.
+			# Also note that these variants do not include a newline at the end.
+			_geodesic_tput_cache["${key}-n"]=$(printf "\x01%s\x02" "${_geodesic_tput_cache["$key"]}")
+			_geodesic_tput_cache["${key}-n-off"]=$(printf "\x01%s\x02" "$color_off")
+			_geodesic_tput_cache["bold-${key}-n"]=$(printf "\x01%s%s\x02" "$bold" "${_geodesic_tput_cache["$key"]}")
+			_geodesic_tput_cache["bold-${key}-n-off"]=$(printf "\x01%s%s\x02" "$color_off" "$bold_off")
+		fi
+	done
+
+	# Bold is not a color, handle bold without color change separately
+	if [[ -n "$bold"} ]]; then
+		_geodesic_tput_cache["bold"]=$(printf "\x01%s\x02" "$bold")
+		_geodesic_tput_cache["bold-off"]=$(printf "\x01%s\x02" "$bold_off")
+	fi
+
+	# Save the terminal type so we can invalidate the cache if it changes
+	_geodesic_tput_cache[TERM]="$TERM"
+	_geodesic_tput_cache[dark_mode]="$(_is_term_dark_mode -b)"
 }
 
-function yellow() {
-	echo "$(tput setaf 3)$*$(tput setaf 0)"
+# Colorize text using ANSI escape codes.
+# Usage: _geodesic_color style text...
+# `style` is defined by the keys of the associative array _geodesic_tput_cache set up above.
+# Not intended to be called directly. Use the named style functions below.
+function _geodesic_color() {
+	# The -v test is to see if the variable is set.
+	# It is required because the associative array syntax does not work with unset variables.
+	if [[ ! -v _geodesic_tput_cache ]] || [[ "${_geodesic_tput_cache[TERM]}" != "$TERM" ]]; then
+		_geodesic_tput_cache_init
+	fi
+
+	local style=$1
+	shift
+
+	printf "%s%s%s" "${_geodesic_tput_cache["$style"]}" "$*" "${_geodesic_tput_cache["${style}-off"]}"
 }
 
-function cyan() {
-	echo "$(tput setaf 6)$*$(tput setaf 0)"
+# Named style helpers
+#
+# For each color there is "color" and "bold-color", where "bold-color" is the bold version of the color.
+#
+# These come in 2 flavors.
+# - The plain ones include a newline in the end and do not include delimiters around the non-printing text.
+# - The ones ending with "-n" do not include a newline and do include delimiters around the non-printing text.
+#
+# Note that the newline is stripped if run via command substitution, so
+#   echo "$(red "Hello") World"
+# will not have a newline between "Hello" and "World".
+# However, you should still use the "-n" variants if your string is or might become part of a PS1 prompt.
+# Otherwise, bash will not correctly calculate the visible length of the prompt and editing command history will break.
+#
+# We intentionally do not define blue or magenta, as blue is problematic in dark mode
+# and magenta is too much like red in dark mode, plus it is used as a substitute for yellow in light mode.
+# We do not define white or black, either, as we should use the terminal's default for those.
+# However, those colors are available via _geodesic_color() if needed, and "white" and "black" are
+# swapped in dark mode, so they are more appropriately called "bg" and "fg" respectively.
+# Also, "yellow" is not necessarily yellow, it varies with the terminal theme, and
+# would be better named "caution" or "info".
+
+function _generate_color_functions() {
+	local color
+	for color in red green yellow cyan; do
+		eval "function ${color}() { _geodesic_color ${color} \"\$*\"; }"
+		eval "bold-${color}() { _geodesic_color bold-${color} \"\$*\"; }"
+		eval "function ${color}-n() { _geodesic_color ${color}-n \"\$*\"; }"
+		eval "bold-${color}-n() { _geodesic_color bold-${color}-n \"\$*\"; }"
+	done
 }
 
-# Turning on bold is a standard `tput` attribute, but turning it off is not.
-# However, turning off bold is an ECMA standard (SGR 22), so it is not
-# unreasonable for us to use it. If it causes problems, people can set
-#   export TERM_BOLD_OFF=$(tput sgr0)
-# http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf
+_generate_color_functions
+unset _generate_color_functions
+
 function bold() {
-	local bold=$(tput bold)
-	local boldoff=${TERM_BOLD_OFF:-$'\033[22m'}
-	# If the terminal supports color
-	if [[ -n $bold ]]; then
-		printf "%s%s%s\n" "$bold" "$*" "$boldoff"
-	else
-		# The terminal does not support color
-		printf "%s\n" "$*"
-	fi
+	_geodesic_color bold "$*"
+}
+
+# Actually, resets all graphics settings to their defaults.
+function reset_terminal_colors() {
+	tput sgr0
 }

rootfs/etc/profile.d/_30-geodesic-config.sh

@@ -85,6 +85,7 @@ function _expand_dir_or_file() {
 
 	[[ -n $_GEODESIC_TRACE_CUSTOMIZATION ]] && echo trace: looking for resources of type "$resource" in "$dir"
 
+  local item
 	for item in "${dir}/$resource" "${dir}/${resource}.d"/*; do
 		if [[ -f $item ]]; then
 			[[ $item =~ $exclude ]] && ([[ -n $_GEODESIC_TRACE_CUSTOMIZATION ]] && echo trace: excluding "$item" || true) && continue

rootfs/etc/profile.d/_40-preferences.sh

@@ -85,6 +85,7 @@ function _load_geodesic_preferences() {
 	[[ -n $_GEODESIC_TRACE_CUSTOMIZATION ]] && echo trace: LOADING preference files
 
 	_search_geodesic_dirs preference_list preferences
+	local file
 	for file in "${preference_list[@]}"; do
 		[[ -n $_GEODESIC_TRACE_CUSTOMIZATION ]] && echo trace: loading preference file "$file"
 		source "$file"

rootfs/etc/profile.d/aws.sh

@@ -21,11 +21,12 @@ if [ ! -f "${AWS_CONFIG_FILE:=${GEODESIC_AWS_HOME}/config}" ] && [ -d ${GEODESIC
 fi
 
 # Install autocompletion rules for aws CLI v1 and v2
-for aws in aws aws1 aws2; do
-	if command -v ${aws}_completer >/dev/null; then
-	complete -C "$(command -v ${aws}_completer)" ${aws}
+for __aws in aws aws1 aws2; do
+	if command -v ${__aws}_completer >/dev/null; then
+	complete -C "$(command -v ${__aws}_completer)" ${__aws}
 	fi
 done
+unset __aws
 
 # This is the default assume-role function, but it can be overridden/replaced later
 # by aws-okta or aws-vault, etc. or could have already been overridden.