[ccan] [PATCH v2] pr_log: a new module that provides a simple run-time controlled logging interface
Cody P Schafer
dev at codyps.com
Wed Aug 19 12:29:54 AEST 2015
A simple printf logging infra where levels are determined 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 implementation 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.
Signed-off-by: Cody P Schafer <dev at codyps.com>
---
I've updated this to:
- Make it more clear that the pr_<level>() macros are the expected interface
- remove some old prefix experiments from the docs
- make ccanlint pass the module fully (with some added tests)
---
Makefile-ccan | 1 +
ccan/pr_log/LICENSE | 1 +
ccan/pr_log/_info | 40 +++++++++++++++++++++++
ccan/pr_log/pr_log.c | 48 ++++++++++++++++++++++++++++
ccan/pr_log/pr_log.h | 72 ++++++++++++++++++++++++++++++++++++++++++
ccan/pr_log/test/run-debug.c | 38 ++++++++++++++++++++++
ccan/pr_log/test/run-disable.c | 37 ++++++++++++++++++++++
ccan/pr_log/test/run.c | 43 +++++++++++++++++++++++++
8 files changed, 280 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-debug.c
create mode 100644 ccan/pr_log/test/run-disable.c
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..7f4feb6
--- /dev/null
+++ b/ccan/pr_log/_info
@@ -0,0 +1,40 @@
+#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_info("Really, it works\n");
+ * pr_emerg("I'm serious %d\n", argc);
+ * 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..1de8cb9
--- /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, ...)
+{
+ 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..8e125b8
--- /dev/null
+++ b/ccan/pr_log/pr_log.h
@@ -0,0 +1,72 @@
+/* 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>
+
+/*
+ * pr_emerg, pr_alert, pr_crit, pr_error, pr_warn, pr_notice, pr_info, pr_debug
+ *
+ * Each of these prints a format string only in the case where we're running at
+ * the selected debug level.
+ *
+ * Note that using these functions also causes a pre-pended log level to be
+ * included in the printed string.
+ *
+ * Log levels correspond to those used in syslog(3) .
+ */
+#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
+
+#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_(LOG_DEBUG "everything is fine\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 -1; }
+#endif
+
+#endif
diff --git a/ccan/pr_log/test/run-debug.c b/ccan/pr_log/test/run-debug.c
new file mode 100644
index 0000000..c898065
--- /dev/null
+++ b/ccan/pr_log/test/run-debug.c
@@ -0,0 +1,38 @@
+#define DEBUG 1
+#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);
+ debug = 3;
+ ok1(!debug_is(4));
+ debug = 1;
+ ok1(debug_is(0));
+ ok1(debug_is(1));
+ ok1(!debug_is(2));
+ ok1(!debug_is(3));
+
+ pr_emerg("Emerg\n");
+ pr_alert("Alert\n");
+ pr_crit("Crit\n");
+ pr_error("Error\n");
+ pr_warn("Warn\n");
+ pr_notice("Notice\n");
+ pr_info("Info\n");
+ pr_debug("Debug\n");
+
+ pr_devel("Devel\n");
+
+ debug = INT_MIN;
+ setenv("DEBUG", "1", 1);
+ ok1(debug_is(1));
+
+ /* malformed check */
+ pr_log_(":4> 1\n");
+ pr_log_("<!> 2\n");
+ pr_log_("<1} 3\n");
+
+ return exit_status();
+}
diff --git a/ccan/pr_log/test/run-disable.c b/ccan/pr_log/test/run-disable.c
new file mode 100644
index 0000000..599a7ed
--- /dev/null
+++ b/ccan/pr_log/test/run-disable.c
@@ -0,0 +1,37 @@
+#define CCAN_PR_LOG_DISABLE 1
+#include <ccan/pr_log/pr_log.h>
+#include <ccan/tap/tap.h>
+#include <stdlib.h>
+
+int main(void)
+{
+ plan_tests(7);
+ ok1(!debug_is(4));
+ ok1(!debug_is(0));
+ ok1(!debug_is(1));
+ ok1(!debug_is(2));
+ ok1(!debug_is(3));
+
+ pr_emerg("Emerg\n");
+ pr_alert("Alert\n");
+ pr_crit("Crit\n");
+ pr_error("Error\n");
+ pr_warn("Warn\n");
+ pr_notice("Notice\n");
+ pr_info("Info\n");
+ pr_debug("Debug\n");
+
+ pr_devel("Devel\n");
+
+ setenv("DEBUG", "1", 1);
+ ok1(!debug_is(1));
+
+ /* malformed check */
+ pr_log_(":4> 1\n");
+ pr_log_("<!> 2\n");
+ pr_log_("<1} 3\n");
+
+ ok1(debug_level() == -1);
+
+ return exit_status();
+}
diff --git a/ccan/pr_log/test/run.c b/ccan/pr_log/test/run.c
new file mode 100644
index 0000000..40c2b1a
--- /dev/null
+++ b/ccan/pr_log/test/run.c
@@ -0,0 +1,43 @@
+#include <ccan/pr_log/pr_log.h>
+#include <ccan/pr_log/pr_log.c>
+#include <ccan/tap/tap.h>
+
+int main(void)
+{
+ plan_tests(8);
+ debug = 3;
+ ok1(!debug_is(4));
+ debug = 1;
+ ok1(debug_is(0));
+ ok1(debug_is(1));
+ ok1(!debug_is(2));
+ ok1(!debug_is(3));
+
+ pr_emerg("Emerg\n");
+ pr_alert("Alert\n");
+ pr_crit("Crit\n");
+ pr_error("Error\n");
+ pr_warn("Warn\n");
+ pr_notice("Notice\n");
+ pr_info("Info\n");
+ pr_debug("Debug\n");
+
+ pr_devel("Devel\n");
+
+ debug = INT_MIN;
+ setenv("DEBUG", "1", 1);
+ ok1(debug_is(1));
+
+ ok1(debug_level() == 1);
+
+ /* malformed check */
+ pr_log_(":4> 1\n");
+ pr_log_("<!> 2\n");
+ pr_log_("<1} 3\n");
+
+ debug = INT_MIN;
+ unsetenv("DEBUG");
+ ok1(debug_level() == CCAN_PR_LOG_DEFAULT_LEVEL);
+
+ return exit_status();
+}
--
2.5.0
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