bees: configurable log verbosity

Log messages were already labelled with log levels, but there was no
way to filter by log level at run time.

Implement the filter inside the bees process so it can skip evaluation
of the BEESLOG* arguments if the log messages would not be emitted.

Fixes: https://github.com/Zygo/bees/issues/67

Signed-off-by: Zygo Blaxell <bees@furryterror.org>

README.md

@@ -561,6 +561,8 @@ Command Line Options
 * --strip-paths (-P)
   * Paths in log output will have the working directory at Bees startup
     stripped.
+* --verbose (-v)
+  * Set log verbosity (0 = no output, 8 = all output, default 8).
 
 
 Bug Reports and Contributions

src/bees.cc

@@ -30,6 +30,8 @@
 using namespace crucible;
 using namespace std;
 
+int bees_log_level = 8;
+
 int
 do_cmd_help(char *argv[])
 {
@@ -48,6 +50,7 @@ do_cmd_help(char *argv[])
 		"\t-T, --no-timestamps\tOmit timestamps in log output\n"
 		"\t-p, --absolute-paths\tShow absolute paths (default)\n"
 		"\t-P, --strip-paths\tStrip $CWD from beginning of all paths in the log\n"
+		"\t-v, --verbose\tSet maximum log level (0..8, default 8)\n"
 		"\n"
 		"Optional environment variables:\n"
 		"\tBEESHOME\tPath to hash table and configuration files\n"
@@ -655,43 +658,54 @@ bees_main(int argc, char *argv[])
 	while (1) {
 		int option_index = 0;
 		static struct option long_options[] = {
-			{ "thread-count",   required_argument, NULL, 'c' },
 			{ "thread-factor",  required_argument, NULL, 'C' },
-			{ "scan-mode", 	    required_argument, NULL, 'm' },
-			{ "timestamps",     no_argument,       NULL, 't' },
-			{ "no-timestamps",  no_argument,       NULL, 'T' },
-			{ "absolute-paths", no_argument,       NULL, 'p' },
 			{ "strip-paths",    no_argument,       NULL, 'P' },
-			{ "help",           no_argument,       NULL, 'h' }
+			{ "no-timestamps",  no_argument,       NULL, 'T' },
+			{ "thread-count",   required_argument, NULL, 'c' },
+			{ "help",           no_argument,       NULL, 'h' },
+			{ "scan-mode", 	    required_argument, NULL, 'm' },
+			{ "absolute-paths", no_argument,       NULL, 'p' },
+			{ "timestamps",     no_argument,       NULL, 't' },
+			{ "verbose",        required_argument, NULL, 'v' },
 		};
 
-		c = getopt_long(argc, argv, "c:C:m:TtPph", long_options, &option_index);
+		c = getopt_long(argc, argv, "C:PTc:hm:ptv:", long_options, &option_index);
 		if (-1 == c) {
 			break;
 		}
 
 		switch (c) {
-			case 'c':
+
-				thread_count = stoul(optarg);
-				break;
 			case 'C':
 				thread_factor = stod(optarg);
 				break;
-			case 'm':
-				BeesRoots::set_scan_mode(static_cast<BeesRoots::ScanMode>(stoul(optarg)));
-				break;
-			case 'T':
-				chatter_prefix_timestamp = false;
-				break;
-			case 't':
-				chatter_prefix_timestamp = true;
-				break;
 			case 'P':
 				crucible::set_relative_path(cwd);
 				break;
+			case 'T':
+				chatter_prefix_timestamp = false;
+				break;
+			case 'c':
+				thread_count = stoul(optarg);
+				break;
+			case 'm':
+				BeesRoots::set_scan_mode(static_cast<BeesRoots::ScanMode>(stoul(optarg)));
+				break;
 			case 'p':
 				crucible::set_relative_path("");
 				break;
+			case 't':
+				chatter_prefix_timestamp = true;
+				break;
+			case 'v':
+				{
+					int new_log_level = stoul(optarg);
+					THROW_CHECK1(out_of_range, new_log_level, new_log_level >= 0 || new_log_level <= 8);
+					bees_log_level = new_log_level;
+					BEESLOGNOTICE("log level set to " << bees_log_level);
+				}
+				break;
+
 			case 'h':
 				do_cmd_help(argv); // fallthrough
 			default:

src/bees.h

@@ -127,7 +127,7 @@ const int FLAGS_OPEN_FANOTIFY = O_RDWR | O_NOATIME | O_CLOEXEC | O_LARGEFILE;
 
 // macros ----------------------------------------
 
-#define BEESLOG(lv,x)   do { Chatter c(lv, BeesNote::get_name()); c << x; } while (0)
+#define BEESLOG(lv,x)   do { if (lv < bees_log_level) { Chatter c(lv, BeesNote::get_name()); c << x; } } while (0)
 #define BEESLOGTRACE(x) do { BEESLOG(LOG_DEBUG, x); BeesTracer::trace_now(); } while (0)
 
 #define BEESTRACE(x)   BeesTracer  SRSLY_WTF_C(beesTracer_,  __LINE__) ([&]()                 { BEESLOG(LOG_ERR, x);   })
@@ -136,7 +136,7 @@ const int FLAGS_OPEN_FANOTIFY = O_RDWR | O_NOATIME | O_CLOEXEC | O_LARGEFILE;
 
 #define BEESLOGERR(x)    BEESLOG(LOG_ERR, x)
 #define BEESLOGWARN(x)   BEESLOG(LOG_WARNING, x)
-#define BEESLOGNOTE(x)  BEESLOG(LOG_NOTICE, x)
+#define BEESLOGNOTICE(x) BEESLOG(LOG_NOTICE, x)
 #define BEESLOGINFO(x)   BEESLOG(LOG_INFO, x)
 #define BEESLOGDEBUG(x)  BEESLOG(LOG_DEBUG, x)
 
@@ -825,6 +825,7 @@ public:
 };
 
 // And now, a giant pile of extern declarations
+extern int bees_log_level;
 extern const char *BEES_VERSION;
 string pretty(double d);
 void bees_sync(int fd);