Re: [tarantool-patches] [PATCH 1/1] Fixed non-informative error messages for log conf.

[Vladimir Davydov <vdavydov.dev@gmail.com>]

On Mon, Jul 30, 2018 at 04:58:01PM +0300, Olga Arkhangelskaia wrote:
> In case of bad or erroneous options for log configurations
> errors had ambiguous or absent messages. In some cases it lead to
> app crashes.
> 
> Closes #3553
> ---
> https://github.com/tarantool/tarantool/issues/3553
> https://github.com/tarantool/tarantool/tree/OKriw/gh-3553-non-inf-error

The branch is based on your other branch for syslog destination. Why?
AFAICS they are not interconnected and can be submitted separately.
Please re-base on 2.0 so that we can push this first.

> 
>  src/box/box.cc            | 25 ++++++++++++++++++-------
>  src/say.c                 | 22 +++++++++++++++-------
>  src/say.h                 |  4 +++-
>  test/box-tap/cfg.test.lua |  2 +-
>  4 files changed, 37 insertions(+), 16 deletions(-)
> 
> diff --git a/src/box/box.cc b/src/box/box.cc
> index b6c22b081..c711cd55a 100644
> --- a/src/box/box.cc
> +++ b/src/box/box.cc
> @@ -353,10 +353,13 @@ apply_initial_join_row(struct xstream *stream, struct xrow_header *row)
>  static void
>  box_check_say()
>  {
> -	const char *log = cfg_gets("log");
> -	if (log == NULL)
> -		return;
>  	enum say_logger_type type;
> +	const char *log = cfg_gets("log");
> +	if (log == NULL) {
> +		type = SAY_LOGGER_STDERR;
> +		goto checks;
> +	}
> +	
>  	if (say_parse_logger_type(&log, &type) < 0) {
>  		tnt_raise(ClientError, ER_CFG, "log",
>  			  diag_last_error(diag_get())->errmsg);

I prefer not to use labels when I can. This place can be easily
rewritten without the goto:

	enum say_logger_type type = SAY_LOGGER_STDERR; /* default */
	const char *log = cfg_gets("log");
	if (log != NULL && say_parse_logger_type(&log, &type) < 0) {
		tnt_raise(ClientError, ER_CFG, "log",
			  diag_last_error(diag_get())->errmsg);
	}
	if (type == SAY_LOGGER_SYSLOG) {
		...

> @@ -375,17 +378,21 @@ box_check_say()
>  		say_free_syslog_opts(&opts);
>  	}
>  
> +checks:
>  	const char *log_format = cfg_gets("log_format");
>  	enum say_format format = say_format_by_name(log_format);
>  	if (format == say_format_MAX)
> -		diag_set(ClientError, ER_CFG, "log_format",
> +		tnt_raise(ClientError, ER_CFG, "log_format",
>  			 "expected 'plain' or 'json'");

This is OK.

>  	if (type == SAY_LOGGER_SYSLOG && format == SF_JSON) {
> -		tnt_raise(ClientError, ER_ILLEGAL_PARAMS, "log, log_format");
> +		tnt_raise(ClientError, ER_CFG, "log, log_format",
> +			  "incompatible values");

The error message would look like:

	Incorrect value for option 'log, log_format': incompatible values

Note 'log, log_format' in quotes and 'option' in singular. Looks ugly.
Let's rewrite it so that it looks like:

	Incorrect value for option 'log_format': 'json' can't be used with syslog logger

or something like that.

>  	}
>  	int log_nonblock = cfg_getb("log_nonblock");
> -	if (log_nonblock == 1 && type == SAY_LOGGER_FILE) {
> -		tnt_raise(ClientError, ER_ILLEGAL_PARAMS, "log, log_nonblock");
> +	if (log_nonblock == 1 &&
> +	    (type == SAY_LOGGER_FILE || type == SAY_LOGGER_STDERR)) {
> +		tnt_raise(ClientError, ER_CFG, "log, log_nonblock",
> +			  "incompatible values");

Ditto: please beautify the error message.

>  	}
>  }
>  
> @@ -745,6 +752,10 @@ void
>  box_set_log_format(void)
>  {
>  	enum say_format format = box_check_log_format(cfg_gets("log_format"));
> +	if (say_set_log_format(format) < 0) {
> +		 tnt_raise(ClientError, ER_CFG, "log_format",
> +		           diag_last_error(diag_get())->errmsg);
> +	}
>  	say_set_log_format(format);

say_set_log_format() is called twice, which doesn't look right.

Ideally, the error message should look exactly like the one emitted by
box_check_say(). May be, you could simply call box_check_say() from
box_set_log_format()?

>  }
>  
> diff --git a/src/say.c b/src/say.c
> index b4836d9ee..8753bb865 100644
> --- a/src/say.c
> +++ b/src/say.c
> @@ -190,7 +190,7 @@ say_set_log_level(int new_level)
>  	log_set_level(log_default, (enum say_level) new_level);
>  }
>  
> -void
> +int
>  say_set_log_format(enum say_format format)

I guess if you called box_check_say() from box_set_log_format(), you
could simply add some assertions making sure that log format is
compatible with logger type instead of allowing this function to return
an error.

>  {
>  	/*
> @@ -204,22 +204,25 @@ say_set_log_format(enum say_format format)
>  	case SF_JSON:
>  
>  		if (!allowed_to_change) {
> -			say_error("json log format is not supported when output is '%s'",
> +			diag_set(IllegalParams,
> +				 "json log format is incompatible with '%s'log",
>  				  say_logger_type_strs[log_default->type]);
> -			return;
> +			return -1;
>  		}
>  		log_set_format(log_default, say_format_json);
>  		break;
>  	case SF_PLAIN:
>  		if (!allowed_to_change) {
> -			return;
> +			return 0;
>  		}
>  		log_set_format(log_default, say_format_plain);
>  		break;
>  	default:
> -		unreachable();
> +		diag_set(IllegalParams, "unsupported log_format, expected plain or json");
> +		return -1;
>  	}
>  	log_format = format;
> +	return 0;
>  }
>  
>  static const char *say_format_strs[] = {
> @@ -692,7 +695,8 @@ say_logger_init(const char *init_str, int level, int nonblock,
>  	say_set_log_level(level);
>  	log_background = background;
>  	log_pid = log_default->pid;
> -	say_set_log_format(say_format_by_name(format));
> +	if (say_set_log_format(say_format_by_name(format)) < 0)
> +		goto error;
>  
>  	if (background) {
>  		fflush(stderr);
> @@ -715,6 +719,8 @@ say_logger_init(const char *init_str, int level, int nonblock,
>  fail:
>  	diag_log();
>  	panic("failed to initialize logging subsystem");
> +error:
> +	diag_log();

panic() seems to be missing.

>  }
>  
>  void
> @@ -1071,8 +1077,10 @@ say_parse_logger_type(const char **str, enum say_logger_type *type)
>  		*type = SAY_LOGGER_SYSLOG;
>  	else if (strchr(*str, ':') == NULL)
>  		*type = SAY_LOGGER_FILE;
> -	else
> +	else {
> +		diag_set(IllegalParams, "unrecognized log type '%s'", *str);
>  		return -1;
> +	}

I think you should print logger_syntax_reminder instead, just like
log_create() does. You could remove diag_set from log_create() then.

>  	return 0;
>  }
>  
> diff --git a/src/say.h b/src/say.h
> index 6681aae98..9a76e07f3 100644
> --- a/src/say.h
> +++ b/src/say.h
> @@ -222,8 +222,10 @@ say_set_log_level(int new_level);
>   *
>   * Can't be applied in case syslog or boot (will be ignored)
>   * @param say format
> + * @retval 0 on success
> + * @retvel -1 on failure

s/retvel/retval

>   */
> -void
> +int
>  say_set_log_format(enum say_format format);
>  
>  /**
> diff --git a/test/box-tap/cfg.test.lua b/test/box-tap/cfg.test.lua
> index 629faefaa..d0a635e33 100755
> --- a/test/box-tap/cfg.test.lua
> +++ b/test/box-tap/cfg.test.lua
> @@ -51,7 +51,7 @@ invalid('vinyl_bloom_fpr', 1.1)
>  
>  local function invalid_combinations(name, val)
>      local status, result = pcall(box.cfg, val)
> -    test:ok(not status and result:match('Illegal'), 'invalid '..name)
> +    test:ok(not status and result:match('Incorrect'), 'incompatible values'..name)

I expect you to add some more tests that would check all the cases
I mentioned in the ticket.

>  end
>  
>  invalid_combinations("log, log_nonblock", {log = "1.log", log_nonblock = true})