Add colorized output

[ivanpauno]

It is just what the title says.

Working well in Linux. Colors were taken from ROS1:
https://github.com/ros/rosconsole/blob/ba4e1ae06b5bce3039ac5d20853248b51198e431/src/rosconsole/rosconsole.cpp#L75-L85
https://github.com/ros/rosconsole/blob/ba4e1ae06b5bce3039ac5d20853248b51198e431/src/rosconsole/rosconsole.cpp#L341-L363

I haven't tried it on MAC, but as far as I understand it should work as-is.

I could do something like this in windows if it is desired:
https://stackoverflow.com/questions/8765938/colorful-text-using-printf-in-c

[dirk-thomas]

It would be good to have an env var to control the behavior (force enable, force disable) and the default could be based on if the shell is interactive (if I recall correctly that is what other cases use).

[ivanpauno]

It would be good to have an env var to control the behavior (force enable, force disable) and the default could be based on if the shell is interactive (if I recall correctly that is what other cases use).

I added an env RCUTILS_COLORIZED_OUTPUT, possible values: FORCE_ENABLE, FORCE_DISABLE, DEFAULT.
I used isatty for checking if it is a terminal or not as default behavior.

I also moved the "add colour logic " from rcutils_logging_format_message to rcutils_logging_console_output_handler, as the first function is also used for formatting a message in other log functions (rcl/src/logging.c: rcl_logging_ext_lib_output_handler). I suppose we don't want to colorize that output.

[ivanpauno]

An unrelated comment:
I think rcutils_logging_initialize is using strcmp in the wrong way with line_buffered (L83 and L86).

rcutils/src/logging.c

Lines 77 to 98 in 343e406

	rcutils_ret_t rcutils_logging_initialize(void)
	{
	const char * line_buffered;
	const char * ret_str = rcutils_get_env("RCUTILS_CONSOLE_STDOUT_LINE_BUFFERED", &line_buffered);
	if (NULL == ret_str) {
	if (strcmp(line_buffered, "1")) {
	g_force_stdout_line_buffered = true;
	} else {
	if (!strcmp(line_buffered, "0")) {
	fprintf(stderr,
	"Warning: unexpected value [%s] specified for RCUTILS_CONSOLE_STDOUT_LINE_BUFFERED. "
	"Default value 0 will be used. Valid values are 1 or 0.\n",
	line_buffered);
	}
	}
	} else {
	fprintf(stderr, "Error getting env. variable "
	"RCUTILS_CONSOLE_STDOUT_LINE_BUFFERED: %s\n", ret_str);
	}
	return rcutils_logging_initialize_with_allocator(rcutils_get_default_allocator());
	}

Also, I think all the code related to RCUTILS_CONSOLE_STDOUT_LINE_BUFFERED should be moved to rcutils_logging_initialize_with_allocator.

@dirk-thomas if you agree, I will open another PR correcting that.

[dirk-thomas]

possible values: FORCE_ENABLE, FORCE_DISABLE, DEFAULT.

Let's use standard boolean values for the new env var RCUTILS_COLORIZED_OUTPUT: 0 to disable the colorization, 1 to force using colorization and when no value is set use the automatic decision based on isatty.

[ivanpauno]

possible values: FORCE_ENABLE, FORCE_DISABLE, DEFAULT.

Let's use standard boolean values for the new env var RCUTILS_COLORIZED_OUTPUT: 0 to disable the colorization, 1 to force using colorization and when no value is set use the automatic decision based on isatty.

Done!
Internally, I'm still using an enum with the three possibilities, as I have to defer the decision depending if the output stream is stdout or stderr.

[dirk-thomas]

This macro is almost identical to the Windows implementation above. Please avoid that duplication and only customize the isatty call using a platform specific macro.

[ivanpauno]

CI:

• Linux (uncrustify failures and unrelated)
• Linux-aarch64 (uncrustify failures and unrelated)
• macOS (uncrustify failures and unrelated)
• Windows (uncrustify failures, cppcheck false positive and unrelated)

[ivanpauno]

I have tested locally that linter is passing in both windows and linux after e407efd. I'm going to skip running ci jobs again only because of linter failures.

[peci1]

Just to keep information in one place, I'll amend to this years old PR.

When using ros2 launch, the nodes have isatty == False for both stdout and stderr. So to get colorized output of ros2 launch, you have to force it using the env variable.

I've added a documentation note about this caveat: ros2/ros2_documentation#5726 .