[ccan] [PATCH] pr_log: a new module that provides a simple run-time controlled logging interface
Rusty Russell
rusty at rustcorp.com.au
Mon Aug 17 11:52:22 AEST 2015
Cody P Schafer <dev at codyps.com> writes:
> A simple printf logging infra where levels are detemined by the
> value of the "DEBUG" environment variable.
>
> This is loosely based on the interfaces & functionality of Linux's
> printk() and pr_*() wrapper macros.
>
> Note that the current implimentation uses "<N>" prefixes (where N is a
> syslog level in ascii), allowing other programs that parse log output
> (like systemd's journald) to know what the priority level is.
I like the idea, but I can't believe you're seriously proposing
imitating the kernel interface. You know they're deprecating printk()
without the level arg, right?
I mean, it's OK if you want to add <N> to the output, but it's weird
from an API POV.
Cheers,
Rusty.
PS. You don't have to change it: the rule is that I will accept any
well-formed module. I was just a bit surprised...
> Signed-off-by: Cody P Schafer <dev at codyps.com>
> ---
> Makefile-ccan | 1 +
> ccan/pr_log/LICENSE | 1 +
> ccan/pr_log/_info | 41 +++++++++++++++++++++++++++++++++
> ccan/pr_log/pr_log.c | 48 +++++++++++++++++++++++++++++++++++++++
> ccan/pr_log/pr_log.h | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++
> ccan/pr_log/test/run.c | 24 ++++++++++++++++++++
> 6 files changed, 176 insertions(+)
> create mode 120000 ccan/pr_log/LICENSE
> create mode 100644 ccan/pr_log/_info
> create mode 100644 ccan/pr_log/pr_log.c
> create mode 100644 ccan/pr_log/pr_log.h
> create mode 100644 ccan/pr_log/test/run.c
>
> diff --git a/Makefile-ccan b/Makefile-ccan
> index 99c4910..8d13a4f 100644
> --- a/Makefile-ccan
> +++ b/Makefile-ccan
> @@ -88,6 +88,7 @@ MODS_WITH_SRC := aga \
> ogg_to_pcm \
> opt \
> order \
> + pr_log \
> ptrint \
> ptr_valid \
> pushpull \
> diff --git a/ccan/pr_log/LICENSE b/ccan/pr_log/LICENSE
> new file mode 120000
> index 0000000..dc314ec
> --- /dev/null
> +++ b/ccan/pr_log/LICENSE
> @@ -0,0 +1 @@
> +../../licenses/LGPL-2.1
> \ No newline at end of file
> diff --git a/ccan/pr_log/_info b/ccan/pr_log/_info
> new file mode 100644
> index 0000000..021933f
> --- /dev/null
> +++ b/ccan/pr_log/_info
> @@ -0,0 +1,41 @@
> +#include <string.h>
> +#include "config.h"
> +
> +/**
> + * pr_log - print things with varying levels of importance
> + *
> + * pr_log is a "logger" styled similarly to Linux's printk() and pr_*() macros.
> + * The amount of debug output is controlled by the value of the `DEBUG`
> + * environment variable.
> + *
> + * It provides work-alikes for Linux's pr_devel, pr_debug, pr_info, etc macros.
> + *
> + * Example:
> + * #include <ccan/pr_log/pr_log.h>
> + *
> + * int main(int argc, char *argv[])
> + * {
> + * pr_debug("It's working\n");
> + * pr_log("I: Informational %d\n", 3);
> + * pr_log("-9: Really important\n");
> + * pr_log("9: Really un-important\n");
> + * return 0;
> + * }
> + *
> + * License: LGPL (v2.1 or any later version)
> + * Author: Cody P Schafer <dev at codyps.com>
> + */
> +int main(int argc, char *argv[])
> +{
> + /* Expect exactly one argument */
> + if (argc != 2)
> + return 1;
> +
> + if (strcmp(argv[1], "depends") == 0) {
> + printf("ccan/compiler\n");
> + printf("ccan/str\n");
> + return 0;
> + }
> +
> + return 1;
> +}
> diff --git a/ccan/pr_log/pr_log.c b/ccan/pr_log/pr_log.c
> new file mode 100644
> index 0000000..dc2b890
> --- /dev/null
> +++ b/ccan/pr_log/pr_log.c
> @@ -0,0 +1,48 @@
> +/* Licensed under LGPLv2.1+ - see LICENSE file for details */
> +#include "pr_log.h"
> +
> +#include <ctype.h>
> +#include <stdarg.h>
> +#include <stdbool.h>
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <limits.h>
> +
> +#include <ccan/str/str.h>
> +
> +#define DEBUG_NEED_INIT INT_MIN
> +static int debug = DEBUG_NEED_INIT;
> +
> +bool debug_is(int lvl)
> +{
> + return lvl <= debug_level();
> +}
> +
> +int debug_level(void)
> +{
> + if (debug != DEBUG_NEED_INIT)
> + return debug;
> + char *c = getenv("DEBUG");
> + if (!c) {
> + debug = CCAN_PR_LOG_DEFAULT_LEVEL;
> + return debug;
> + }
> +
> + debug = atoi(c);
> + return debug;
> +}
> +
> +void pr_log(char const fmt[static 1], ...)
> +{
> + int level = INT_MIN;
> + if (fmt[0] == '<' && cisdigit(fmt[1]) && fmt[2] == '>')
> + level = fmt[1] - '0';
> +
> + if (!debug_is(level))
> + return;
> +
> + va_list va;
> + va_start(va, fmt);
> + vfprintf(stderr, fmt, va);
> + va_end(va);
> +}
> diff --git a/ccan/pr_log/pr_log.h b/ccan/pr_log/pr_log.h
> new file mode 100644
> index 0000000..628b826
> --- /dev/null
> +++ b/ccan/pr_log/pr_log.h
> @@ -0,0 +1,61 @@
> +/* Licensed under LGPLv2.1+ - see LICENSE file for details */
> +#ifndef CCAN_PR_LOG_H_
> +#define CCAN_PR_LOG_H_
> +
> +#include <stdbool.h>
> +#include <ccan/compiler/compiler.h>
> +
> +#ifndef CCAN_PR_LOG_DEFAULT_LEVEL
> +# define CCAN_PR_LOG_DEFAULT_LEVEL 6
> +#endif
> +
> +#define LOG_EMERG "<0>"
> +#define LOG_ALERT "<1>"
> +#define LOG_CRIT "<2>"
> +#define LOG_ERROR "<3>"
> +#define LOG_WARN "<4>"
> +#define LOG_NOTICE "<5>"
> +#define LOG_INFO "<6>"
> +#define LOG_DEBUG "<7>"
> +
> +#ifndef CCAN_PR_LOG_DISABLE
> +/**
> + * pr_log - print output based on the given logging level
> + *
> + * Example:
> + *
> + * pr_log(LOG_EMERG "something went terribly wrong\n");
> + * pr_log("N: notice this printout\n");
> + */
> +void PRINTF_FMT(1,2) pr_log(char const *fmt, ...);
> +bool debug_is(int lvl);
> +int debug_level(void);
> +#else
> +static PRINTF_FMT(1,2) inline void pr_log(char const *fmt, ...)
> +{
> + (void)fmt;
> +}
> +static inline bool debug_is(int lvl) { (void)lvl; return false; }
> +static inline int debug_level(void) { return 0; }
> +#endif
> +
> +#define pr_emerg(...) pr_log(LOG_EMERG __VA_ARGS__)
> +#define pr_alert(...) pr_log(LOG_ALERT __VA_ARGS__)
> +#define pr_crit(...) pr_log(LOG_CRIT __VA_ARGS__)
> +#define pr_error(...) pr_log(LOG_ERROR __VA_ARGS__)
> +#define pr_warn(...) pr_log(LOG_WARN __VA_ARGS__)
> +#define pr_notice(...) pr_log(LOG_NOTICE __VA_ARGS__)
> +#define pr_info(...) pr_log(LOG_INFO __VA_ARGS__)
> +#define pr_debug(...) pr_log(LOG_DEBUG __VA_ARGS__)
> +
> +#ifdef DEBUG
> +# define pr_devel(...) pr_debug(__VA_ARGS__)
> +#else
> +static PRINTF_FMT(1,2) inline void pr_check_printf_args(const char *fmt, ...)
> +{
> + (void)fmt;
> +}
> +# define pr_devel(...) pr_check_printf_args(__VA_ARGS__)
> +#endif
> +
> +#endif
> diff --git a/ccan/pr_log/test/run.c b/ccan/pr_log/test/run.c
> new file mode 100644
> index 0000000..fe60bf2
> --- /dev/null
> +++ b/ccan/pr_log/test/run.c
> @@ -0,0 +1,24 @@
> +#include <ccan/pr_log/pr_log.h>
> +#include <ccan/pr_log/pr_log.c>
> +#include <ccan/tap/tap.h>
> +
> +int main(void)
> +{
> + plan_tests(6);
> + ok1(!debug_is(4));
> + debug = 1;
> + ok1(debug_is(0));
> + ok1(debug_is(1));
> + ok1(!debug_is(2));
> + ok1(!debug_is(3));
> +
> + pr_log("N: notice\n");
> + pr_log("-3: something important\n");
> + pr_log("1: less important\n");
> + pr_log("X: bad level is treated as HIGH\n");
> +
> + debug = INT_MIN;
> + setenv("DEBUG", "1", 1);
> + ok1(debug_is(1));
> + return exit_status();
> +}
> --
> 2.5.0
>
> _______________________________________________
> ccan mailing list
> ccan at lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/ccan
More information about the ccan
mailing list