[dpdk-dev] [PATCH] rte_metrics: unconditionally export rte_metrics_tel_xxx functions

[Jie <jizh@linux.microsoft.com>]

From: Jie Zhou <jizh@microsoft.com>

This patch allows the same set of rte_metrics_tel_* functions to be
exported no matter JANSSON is available or not, by doing following:
1.	Leverage dpdk_conf to set configuration flag RTE_HAVE_JANSSON
when Jansson dependency is found.
2.	In rte_metrics_telemetry.c, leverage RTE_HAVE_JANSSON to handle the
case when JANSSON is not available by adding stubs for all the instances.
3.	In meson.build, per dpdk\doc\guides\rel_notes\release_20_05.rst,
it is claimed that "Telemetry library is no longer dependent on the
external Jansson library, which allows Telemetry be enabled by default.",
thus make the deps and includes of Telemetry as not conditional anymore.

Signed-off-by: Jie Zhou <jizh@microsoft.com>
---
 config/meson.build                         |  5 ++
 lib/librte_metrics/meson.build             | 13 +++---
 lib/librte_metrics/rte_metrics_telemetry.c | 53 ++++++++++++++++++++++
 lib/librte_metrics/rte_metrics_telemetry.h |  2 +-
 4 files changed, 66 insertions(+), 7 deletions(-)

diff --git a/config/meson.build b/config/meson.build
index 3cf560b8a..892bd9677 100644
--- a/config/meson.build
+++ b/config/meson.build
@@ -292,6 +292,11 @@ if is_freebsd
 	add_project_arguments('-D__BSD_VISIBLE', language: 'c')
 endif
 
+jansson = dependency('jansson', required: false, method: 'pkg-config')
+if jansson.found()
+	dpdk_conf.set('RTE_HAVE_JANSSON', 1)
+endif
+
 if is_windows
 	# VirtualAlloc2() is available since Windows 10 / Server 2016.
 	add_project_arguments('-D_WIN32_WINNT=0x0A00', language: 'c')
diff --git a/lib/librte_metrics/meson.build b/lib/librte_metrics/meson.build
index 28a8cc115..b13604c88 100644
--- a/lib/librte_metrics/meson.build
+++ b/lib/librte_metrics/meson.build
@@ -4,11 +4,12 @@
 sources = files('rte_metrics.c')
 headers = files('rte_metrics.h')
 
-jansson = dependency('jansson', required: false, method: 'pkg-config')
-if jansson.found()
+if dpdk_conf.has('RTE_HAVE_JANSSON')
 	ext_deps += jansson
-	sources += files('rte_metrics_telemetry.c')
-	headers += files('rte_metrics_telemetry.h')
-	deps += ['ethdev', 'telemetry']
-	includes += include_directories('../librte_telemetry')
 endif
+
+sources += files('rte_metrics_telemetry.c')
+headers += files('rte_metrics_telemetry.h')
+
+deps += ['ethdev', 'telemetry']
+includes += include_directories('../librte_telemetry')
diff --git a/lib/librte_metrics/rte_metrics_telemetry.c b/lib/librte_metrics/rte_metrics_telemetry.c
index b8ee56ef0..225d9ebce 100644
--- a/lib/librte_metrics/rte_metrics_telemetry.c
+++ b/lib/librte_metrics/rte_metrics_telemetry.c
@@ -2,7 +2,9 @@
  * Copyright(c) 2020 Intel Corporation
  */
 
+#ifdef RTE_HAVE_JANSSON
 #include <jansson.h>
+#endif
 
 #include <rte_ethdev.h>
 #include <rte_string_fns.h>
@@ -13,6 +15,7 @@
 #include "rte_metrics.h"
 #include "rte_metrics_telemetry.h"
 
+#ifdef RTE_HAVE_JANSSON
 struct telemetry_metrics_data tel_met_data;
 
 int metrics_log_level;
@@ -70,10 +73,12 @@ rte_metrics_tel_reg_port_ethdev_to_metrics(uint16_t port_id)
 	free(xstats_names);
 	return ret;
 }
+#endif
 
 int32_t
 rte_metrics_tel_reg_all_ethdev(int *metrics_register_done, int *reg_index_list)
 {
+#ifdef JANSSON
 	struct driver_index {
 		const void *dev_ops;
 		int reg_index;
@@ -110,8 +115,15 @@ rte_metrics_tel_reg_all_ethdev(int *metrics_register_done, int *reg_index_list)
 	}
 	*metrics_register_done = 1;
 	return 0;
+#else
+	RTE_SET_USED(metrics_register_done);
+	RTE_SET_USED(reg_index_list);
+
+	return -ENOTSUP;
+#endif
 }
 
+#ifdef RTE_HAVE_JANSSON
 static int32_t
 rte_metrics_tel_update_metrics_ethdev(uint16_t port_id, int reg_start_index)
 {
@@ -224,11 +236,13 @@ rte_metrics_tel_format_port(uint32_t pid, json_t *ports,
 	free(names);
 	return ret;
 }
+#endif
 
 int32_t
 rte_metrics_tel_encode_json_format(struct telemetry_encode_param *ep,
 		char **json_buffer)
 {
+#ifdef JANSSON
 	json_t *root, *ports;
 	int ret, i;
 
@@ -276,12 +290,19 @@ rte_metrics_tel_encode_json_format(struct telemetry_encode_param *ep,
 	*json_buffer = json_dumps(root, JSON_INDENT(2));
 	json_decref(root);
 	return 0;
+#else
+	RTE_SET_USED(ep);
+	RTE_SET_USED(json_buffer);
+
+	return -ENOTSUP;
+#endif
 }
 
 int32_t
 rte_metrics_tel_get_ports_stats_json(struct telemetry_encode_param *ep,
 		int *reg_index, char **json_buffer)
 {
+#ifdef RTE_HAVE_JANSSON
 	int ret, i;
 	uint32_t port_id;
 
@@ -306,11 +327,19 @@ rte_metrics_tel_get_ports_stats_json(struct telemetry_encode_param *ep,
 		return ret;
 	}
 	return 0;
+#else
+	RTE_SET_USED(ep);
+	RTE_SET_USED(reg_index);
+	RTE_SET_USED(json_buffer);
+
+	return -ENOTSUP;
+#endif
 }
 
 int32_t
 rte_metrics_tel_get_port_stats_ids(struct telemetry_encode_param *ep)
 {
+#ifdef RTE_HAVE_JANSSON
 	int p, num_port_ids = 0;
 
 	RTE_ETH_FOREACH_DEV(p) {
@@ -327,8 +356,14 @@ rte_metrics_tel_get_port_stats_ids(struct telemetry_encode_param *ep)
 	ep->pp.num_metric_ids = 0;
 	ep->type = PORT_STATS;
 	return 0;
+#else
+	RTE_SET_USED(ep);
+
+	return -ENOTSUP;
+#endif
 }
 
+#ifdef RTE_HAVE_JANSSON
 static int32_t
 rte_metrics_tel_stat_names_to_ids(const char * const *stat_names,
 	uint32_t *stat_ids, int num_stat_names)
@@ -373,10 +408,12 @@ rte_metrics_tel_stat_names_to_ids(const char * const *stat_names,
 	free(names);
 	return 0;
 }
+#endif
 
 int32_t
 rte_metrics_tel_extract_data(struct telemetry_encode_param *ep, json_t *data)
 {
+#ifdef RTE_HAVE_JANSSON
 	int ret;
 	json_t *port_ids_json = json_object_get(data, "ports");
 	json_t *stat_names_json = json_object_get(data, "stats");
@@ -420,8 +457,23 @@ rte_metrics_tel_extract_data(struct telemetry_encode_param *ep, json_t *data)
 
 	ep->type = PORT_STATS;
 	return 0;
+#else
+	RTE_SET_USED(ep);
+	RTE_SET_USED(data);
+
+	return -ENOTSUP;
+#endif
+}
+
+int32_t
+rte_metrics_tel_get_global_stats(struct telemetry_encode_param* ep)
+{
+	RTE_SET_USED(ep);
+
+	return -ENOTSUP;
 }
 
+#ifdef RTE_HAVE_JANSSON
 static int
 rte_metrics_tel_initial_metrics_setup(void)
 {
@@ -541,3 +593,4 @@ RTE_INIT(metrics_ctor)
 			handle_ports_stats_values_by_name);
 #endif
 }
+#endif
diff --git a/lib/librte_metrics/rte_metrics_telemetry.h b/lib/librte_metrics/rte_metrics_telemetry.h
index 5dbb32ca0..efc6b9a9e 100644
--- a/lib/librte_metrics/rte_metrics_telemetry.h
+++ b/lib/librte_metrics/rte_metrics_telemetry.h
@@ -2,7 +2,7 @@
  * Copyright(c) 2020 Intel Corporation
  */
 
-#ifdef RTE_LIB_TELEMETRY
+#ifdef RTE_HAVE_JANSSON
 #include <jansson.h>
 #else
 #define json_t void *
-- 
2.30.0.vfs.0.2