metrics: export telemetry stubs if no libjansson

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_HAS_JANSSON
when Jansson dependency is found.
2.	In rte_metrics_telemetry.c, leverage RTE_HAS_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>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>

diff --git a/lib/librte_metrics/meson.build b/lib/librte_metrics/meson.build
index 28a8cc1..d5be6a2 100644 (file)
--- a/lib/librte_metrics/meson.build
+++ b/lib/librte_metrics/meson.build
@@ -1,14 +1,13 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright(c) 2017 Intel Corporation
 
-sources = files('rte_metrics.c')
-headers = files('rte_metrics.h')
+sources = files('rte_metrics.c', 'rte_metrics_telemetry.c')
+headers = files('rte_metrics.h', 'rte_metrics_telemetry.h')
 
 jansson = dependency('jansson', required: false, method: 'pkg-config')
 if jansson.found()
+       dpdk_conf.set('RTE_HAS_JANSSON', 1)
        ext_deps += jansson
-       sources += files('rte_metrics_telemetry.c')
-       headers += files('rte_metrics_telemetry.h')
-       deps += ['ethdev', 'telemetry']
-       includes += include_directories('../librte_telemetry')
 endif
+
+deps += ['ethdev', 'telemetry']

diff --git a/lib/librte_metrics/rte_metrics_telemetry.c b/lib/librte_metrics/rte_metrics_telemetry.c
index b8ee56e..795bd29 100644 (file)
--- a/lib/librte_metrics/rte_metrics_telemetry.c
+++ b/lib/librte_metrics/rte_metrics_telemetry.c
@@ -2,8 +2,6 @@
  * Copyright(c) 2020 Intel Corporation
  */
 
-#include <jansson.h>
-
 #include <rte_ethdev.h>
 #include <rte_string_fns.h>
 #ifdef RTE_LIB_TELEMETRY
@@ -13,6 +11,8 @@
 #include "rte_metrics.h"
 #include "rte_metrics_telemetry.h"
 
+#ifdef RTE_HAS_JANSSON
+
 struct telemetry_metrics_data tel_met_data;
 
 int metrics_log_level;
@@ -541,3 +541,62 @@ RTE_INIT(metrics_ctor)
                        handle_ports_stats_values_by_name);
 #endif
 }
+
+#else /* !RTE_HAS_JANSSON */
+
+int32_t
+rte_metrics_tel_reg_all_ethdev(int *metrics_register_done, int *reg_index_list)
+{
+       RTE_SET_USED(metrics_register_done);
+       RTE_SET_USED(reg_index_list);
+
+       return -ENOTSUP;
+}
+
+int32_t
+rte_metrics_tel_encode_json_format(struct telemetry_encode_param *ep,
+       char **json_buffer)
+{
+       RTE_SET_USED(ep);
+       RTE_SET_USED(json_buffer);
+
+       return -ENOTSUP;
+}
+
+int32_t
+rte_metrics_tel_get_ports_stats_json(struct telemetry_encode_param *ep,
+       int *reg_index, char **json_buffer)
+{
+       RTE_SET_USED(ep);
+       RTE_SET_USED(reg_index);
+       RTE_SET_USED(json_buffer);
+
+       return -ENOTSUP;
+}
+
+int32_t
+rte_metrics_tel_get_port_stats_ids(struct telemetry_encode_param *ep)
+{
+       RTE_SET_USED(ep);
+
+       return -ENOTSUP;
+}
+
+int32_t
+rte_metrics_tel_extract_data(struct telemetry_encode_param *ep, json_t *data)
+{
+       RTE_SET_USED(ep);
+       RTE_SET_USED(data);
+
+       return -ENOTSUP;
+}
+
+int32_t
+rte_metrics_tel_get_global_stats(struct telemetry_encode_param *ep)
+{
+       RTE_SET_USED(ep);
+
+       return -ENOTSUP;
+}
+
+#endif /* !RTE_HAS_JANSSON */

diff --git a/lib/librte_metrics/rte_metrics_telemetry.h b/lib/librte_metrics/rte_metrics_telemetry.h
index 5dbb32c..2b6eb1c 100644 (file)
--- 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_HAS_JANSSON
 #include <jansson.h>
 #else
 #define json_t void *