From 8a9364932dafa79e4b83624259ab41a103bfd520 Mon Sep 17 00:00:00 2001
From: Neels Hofmeyr <neels@hofmeyr.de>
Date: Wed, 20 Nov 2019 04:34:23 +0100
Subject: add log_set_cyclic_category_colors()

This is an easy way to ensure that categories generally have differing colors.

For a long time I've wanted to make sure each osmo-* program logs categories in
different colors, but I never really end up doing it: I don't really enjoy
setting logging category colors manually. Maybe we will use this instead?

The function sets library categories and user categories independently, because
if we did both in the same sequence, a new libosmocore category would change
the colors of all user defined logging, or the other way around.

Change-Id: I66592f1dcb8babfec490a5970a736d42c8f42e4f
---
 include/osmocom/core/logging.h   | 23 +++++++++++++++++++++++
 src/logging.c                    | 20 ++++++++++++++++++++
 tests/logging/logging_vty_test.c |  6 +-----
 3 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/include/osmocom/core/logging.h b/include/osmocom/core/logging.h
index 79eec10d..ab20f378 100644
--- a/include/osmocom/core/logging.h
+++ b/include/osmocom/core/logging.h
@@ -146,6 +146,28 @@ void logp(int subsys, const char *file, int line, int cont, const char *format,
 #define OSMO_LOGCOLOR_BRIGHTWHITE "\033[1;37m"
 #define OSMO_LOGCOLOR_END "\033[0;m"
 
+/*! Color constants that can be used in log_info_cat.color.
+ * This list is useful to set distinct logging category colors in a loop.
+ */
+static const char * const osmo_logcolors[] = {
+	OSMO_LOGCOLOR_RED,
+	OSMO_LOGCOLOR_GREEN,
+	OSMO_LOGCOLOR_YELLOW,
+	OSMO_LOGCOLOR_BLUE,
+	OSMO_LOGCOLOR_PURPLE,
+	OSMO_LOGCOLOR_CYAN,
+	OSMO_LOGCOLOR_DARKRED,
+	OSMO_LOGCOLOR_DARKGREEN,
+	OSMO_LOGCOLOR_DARKYELLOW,
+	OSMO_LOGCOLOR_DARKBLUE,
+	OSMO_LOGCOLOR_DARKPURPLE,
+	OSMO_LOGCOLOR_DARKCYAN,
+	OSMO_LOGCOLOR_DARKGREY,
+	OSMO_LOGCOLOR_GREY,
+	OSMO_LOGCOLOR_BRIGHTWHITE,
+	OSMO_LOGCOLOR_NORMAL,
+};
+
 /*! Configuration of single log category / sub-system */
 struct log_category {
 	uint8_t loglevel;	/*!< configured log-level */
@@ -363,6 +385,7 @@ int log_set_context(uint8_t ctx, void *value);
 void log_set_all_filter(struct log_target *target, int);
 
 void log_set_use_color(struct log_target *target, int);
+void log_set_cyclic_category_colors();
 void log_set_print_extended_timestamp(struct log_target *target, int);
 void log_set_print_timestamp(struct log_target *target, int);
 void log_set_print_filename(struct log_target *target, int);
diff --git a/src/logging.c b/src/logging.c
index 4d6224d5..409e23ad 100644
--- a/src/logging.c
+++ b/src/logging.c
@@ -705,6 +705,26 @@ void log_set_use_color(struct log_target *target, int use_color)
 	target->use_color = use_color;
 }
 
+/*! Cycle through all logging categories, setting each to a different color.
+ * osmo_init_logging2() or log_init() *must* have been called before this.
+ */
+void log_set_cyclic_category_colors()
+{
+	int i;
+	struct log_info_cat *cat;
+	OSMO_ASSERT(osmo_log_info);
+	/* even though log_info->cat is defined const, we know that osmo_log_info was allocated during log_init(). */
+	cat = (struct log_info_cat*)osmo_log_info->cat;
+
+	for (i = 0; i < osmo_log_info->num_cat_user; i++) {
+		cat[i].color = osmo_logcolors[i % ARRAY_SIZE(osmo_logcolors)];
+	}
+	/* make sure the library defined categories get the same colors in each program */
+	for (i = osmo_log_info->num_cat_user; i < osmo_log_info->num_cat; i++) {
+		cat[i].color = osmo_logcolors[(i - osmo_log_info->num_cat_user) % ARRAY_SIZE(osmo_logcolors)];
+	}
+}
+
 /*! Enable or disable printing of timestamps while logging
  *  \param[in] target Log target to be affected
  *  \param[in] print_timestamp Enable (1) or disable (0) timestamps
diff --git a/tests/logging/logging_vty_test.c b/tests/logging/logging_vty_test.c
index e7019f61..d563a0d8 100644
--- a/tests/logging/logging_vty_test.c
+++ b/tests/logging/logging_vty_test.c
@@ -91,31 +91,26 @@ static const struct log_info_cat default_categories[] = {
 	[DAA] = {
 		.name = "DAA",
 		.description = "Antropomorphic Armadillos (AA)",
-		.color = "\033[1;31m",
 		.enabled = 1, .loglevel = LOGL_DEBUG,
 	},
 	[DBB] = {
 		.name = "DBB",
 		.description = "Bidirectional Breadspread (BB)",
-		.color = "\033[1;32m",
 		.enabled = 1, .loglevel = LOGL_INFO,
 	},
 	[DCCC] = {
 		.name = "DCCC",
 		.description = "Chaos Communication Congress (CCC)",
-		.color = "\033[1;33m",
 		.enabled = 1, .loglevel = LOGL_NOTICE,
 	},
 	[DDDDD] = {
 		.name = "DDDDD",
 		.description = "Dehydrated Dribbling Duck Dunkers (DDDD)",
-		.color = "\033[1;34m",
 		.enabled = 1, .loglevel = LOGL_ERROR,
 	},
 	[DEEE] = {
 		.name = "DEEE",
 		.description = "Exhaustive Entropy Extraction (EEE)",
-		.color = "\033[1;35m",
 		.enabled = 1, .loglevel = LOGL_FATAL,
 	},
 };
@@ -242,6 +237,7 @@ int main(int argc, char **argv)
 
 	osmo_init_logging2(root_ctx, &log_info);
 	log_enable_multithread();
+	log_set_cyclic_category_colors();
 
 	vty_commands_init();
 
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