[dpdk-dev] [PATCH 06/11] telemetry: format json response when sending stats

[Ciara Power]

This patch adds functionality to create a JSON message in
order to send it to a client socket.

When stats are requested by a client, they are retrieved from
the metrics library and encoded in JSON format.

Signed-off-by: Ciara Power <ciara.power at intel.com>
Signed-off-by: Brian Archbold <brian.archbold at intel.com>
---
 lib/librte_telemetry/rte_telemetry.c | 314 ++++++++++++++++++++++++++++++++++-
 1 file changed, 313 insertions(+), 1 deletion(-)

diff --git a/lib/librte_telemetry/rte_telemetry.c b/lib/librte_telemetry/rte_telemetry.c
index bd09374..ba04d3d 100644
--- a/lib/librte_telemetry/rte_telemetry.c
+++ b/lib/librte_telemetry/rte_telemetry.c
@@ -179,7 +179,7 @@ rte_telemetry_send_error_response(struct telemetry_impl *telemetry,
 		return -EPERM;
 	}
 
-	json_buffer = json_dumps(root, JSON_INDENT(2));
+	json_buffer = json_dumps(root, 0);
 	json_decref(root);
 
 	ret = rte_telemetry_write_to_socket(telemetry, json_buffer);
@@ -190,6 +190,311 @@ rte_telemetry_send_error_response(struct telemetry_impl *telemetry,
 	return 0;
 }
 
+static int
+rte_telemetry_get_metrics(struct telemetry_impl *telemetry, uint32_t port_id,
+	struct rte_metric_value *metrics, struct rte_metric_name *names,
+	int num_metrics)
+{
+	int ret, num_values;
+
+	if (num_metrics < 0) {
+		TELEMETRY_LOG_ERR("Error - Invalid metrics count\n");
+		goto einval_fail;
+	} else if (num_metrics == 0) {
+		TELEMETRY_LOG_ERR("No metrics to display (none have been "
+			"registered)\n");
+		goto eperm_fail;
+	}
+
+	if (metrics == NULL) {
+		TELEMETRY_LOG_ERR("Error - metrics must be initialised.\n");
+		goto einval_fail;
+	}
+
+	if (names == NULL) {
+		TELEMETRY_LOG_ERR("Error - names must be initialised.\n");
+		goto einval_fail;
+	}
+
+	ret = rte_metrics_get_names(names, num_metrics);
+	if (ret < 0 || ret > num_metrics) {
+		TELEMETRY_LOG_ERR("Error - Cannot get metrics names\n");
+		goto eperm_fail;
+	}
+
+	num_values = rte_metrics_get_values(port_id, NULL, 0);
+	ret = rte_metrics_get_values(port_id, metrics, num_values);
+	if (ret < 0 || ret > num_values) {
+		TELEMETRY_LOG_ERR("Error - Cannot get metrics values\n");
+		goto eperm_fail;
+	}
+	return 0;
+
+eperm_fail:
+	ret = rte_telemetry_send_error_response(telemetry, -EPERM);
+	if (ret < 0)
+		TELEMETRY_LOG_ERR("Error - Could not send error\n");
+	return -1;
+
+einval_fail:
+	ret = rte_telemetry_send_error_response(telemetry, -EINVAL);
+	if (ret < 0)
+		TELEMETRY_LOG_ERR("Error - Could not send error\n");
+	return -1;
+
+}
+
+static int32_t
+rte_telemetry_json_format_stat(struct telemetry_impl *telemetry, json_t *stats,
+	const char *metric_name, uint64_t metric_value)
+{
+	int ret;
+	json_t *stat = json_object();
+
+	if (!stat) {
+		TELEMETRY_LOG_ERR("Error - Could not create stat JSON "
+			"object\n");
+		goto eperm_fail;
+	}
+
+	ret = json_object_set_new(stat, "name", json_string(metric_name));
+	if (ret < 0) {
+		TELEMETRY_LOG_ERR("Error - Stat Name field cannot be set\n");
+		goto eperm_fail;
+	}
+
+	ret = json_object_set_new(stat, "value", json_integer(metric_value));
+	if (ret < 0) {
+		TELEMETRY_LOG_ERR("Error - Stat Value field cannot be set\n");
+		goto eperm_fail;
+	}
+
+	ret = json_array_append_new(stats, stat);
+	if (ret < 0) {
+		TELEMETRY_LOG_ERR("Error - Stat cannot be added to stats json "
+			"array\n");
+		goto eperm_fail;
+	}
+	return 0;
+
+eperm_fail:
+	ret = rte_telemetry_send_error_response(telemetry, -EPERM);
+	if (ret < 0)
+		TELEMETRY_LOG_ERR("Error - Could not send error\n");
+	return -1;
+
+}
+
+static int32_t
+rte_telemetry_json_format_port(struct telemetry_impl *telemetry,
+	uint32_t port_id, json_t *ports, uint32_t *metric_ids,
+	uint32_t num_metric_ids)
+{
+	struct rte_metric_value *metrics = 0;
+	struct rte_metric_name *names = 0;
+	int num_metrics, ret;
+
+	num_metrics = rte_metrics_get_names(NULL, 0);
+	if (num_metrics < 0) {
+		TELEMETRY_LOG_ERR("Error - Cannot get metrics count\n");
+		goto einval_fail;
+	} else if (num_metrics == 0) {
+		TELEMETRY_LOG_ERR("Error - No metrics to display (none have "
+			"been registered)\n");
+		goto eperm_fail;
+	}
+
+	metrics = malloc(sizeof(struct rte_metric_value) * num_metrics);
+	names = malloc(sizeof(struct rte_metric_name) * num_metrics);
+	if (metrics == NULL || names == NULL) {
+		TELEMETRY_LOG_ERR("Error - Cannot allocate memory\n");
+		free(metrics);
+		free(names);
+		int err_ret = rte_telemetry_send_error_response(telemetry,
+			-ENOMEM);
+		if (err_ret < 0)
+			TELEMETRY_LOG_ERR("Error - Could not send error\n");
+		return -1;
+	}
+
+	ret  = rte_telemetry_get_metrics(telemetry, port_id, metrics, names,
+		num_metrics);
+	if (ret < 0) {
+		free(metrics);
+		free(names);
+		TELEMETRY_LOG_ERR("Error - rte_telemetry_get_metrics failed\n");
+		return -1;
+	}
+
+	json_t *port = json_object();
+	json_t *stats = json_array();
+	if (!port || !stats) {
+		TELEMETRY_LOG_ERR("Error - Could not create port/stats JSON "
+			"objects\n");
+		goto eperm_fail;
+	}
+
+	ret = json_object_set_new(port, "port", json_integer(port_id));
+	if (ret < 0) {
+		TELEMETRY_LOG_ERR("Error - Port field cannot be set\n");
+		goto eperm_fail;
+	}
+
+	uint32_t i;
+	for (i = 0; i < num_metric_ids; i++) {
+		if (metric_ids[i] >= (uint32_t)num_metrics) {
+			TELEMETRY_LOG_ERR("Error - Metric_id: %d is "
+				"not valid\n", metric_ids[i]);
+			goto einval_fail;
+		}
+
+		int metric_id = metric_ids[i];
+		int metric_index = -1;
+		int metric_name_key = -1;
+		int32_t j;
+
+		for (j = 0; j < num_metrics; j++) {
+			if (metrics[j].key == metric_id) {
+				metric_name_key = metrics[j].key;
+				metric_index = j;
+				break;
+			}
+		}
+
+		if (metric_name_key < 0 || metric_index < 0) {
+			TELEMETRY_LOG_ERR("Error - Could not get metric "
+				"name/index\n");
+			goto eperm_fail;
+		}
+
+		const char *metric_name = names[metric_name_key].name;
+		uint64_t metric_value = metrics[metric_index].value;
+		ret = rte_telemetry_json_format_stat(telemetry, stats,
+			metric_name, metric_value);
+		if (ret < 0) {
+			TELEMETRY_LOG_ERR("Error - Format stat with id: %u "
+				"failed\n", metric_id);
+			free(metrics);
+			free(names);
+			return -1;
+		}
+	}
+
+	if (json_array_size(stats) == 0)
+		ret = json_object_set_new(port, "stats", json_null());
+	else
+		ret = json_object_set_new(port, "stats", stats);
+
+	if (ret < 0) {
+		TELEMETRY_LOG_ERR("Error - Stats object cannot be set\n");
+		goto eperm_fail;
+	}
+
+	ret = json_array_append_new(ports, port);
+	if (ret < 0) {
+		TELEMETRY_LOG_ERR("Error - Port object cannot be added to "
+			"ports array\n");
+		goto eperm_fail;
+	}
+
+	free(metrics);
+	free(names);
+	return 0;
+
+eperm_fail:
+	free(metrics);
+	free(names);
+	ret = rte_telemetry_send_error_response(telemetry, -EPERM);
+	if (ret < 0)
+		TELEMETRY_LOG_ERR("Error - Could not send error\n");
+	return -1;
+
+einval_fail:
+	free(metrics);
+	free(names);
+	ret = rte_telemetry_send_error_response(telemetry, -EINVAL);
+	if (ret < 0)
+		TELEMETRY_LOG_ERR("Error - Could not send error\n");
+	return -1;
+}
+
+static int32_t
+rte_telemetry_encode_json_format(struct telemetry_impl *telemetry,
+	uint32_t *port_ids, uint32_t num_port_ids, uint32_t *metric_ids,
+	uint32_t num_metric_ids, char **json_buffer)
+{
+	int ret;
+	json_t *root, *ports;
+
+	if (num_port_ids <= 0 || num_metric_ids <= 0) {
+		TELEMETRY_LOG_ERR("Error - Please provide port and metric ids "
+			"to query\n");
+		goto einval_fail;
+	}
+
+	ports = json_array();
+	if (!ports) {
+		TELEMETRY_LOG_ERR("Error - Could not create ports JSON "
+			"array\n");
+		goto eperm_fail;
+	}
+
+	uint32_t i;
+	for (i = 0; i < num_port_ids; i++) {
+		if (!rte_eth_dev_is_valid_port(port_ids[i])) {
+			TELEMETRY_LOG_ERR("Error - Port: %d invalid\n",
+				port_ids[i]);
+			goto einval_fail;
+		}
+	}
+
+	for (i = 0; i < num_port_ids; i++) {
+		ret = rte_telemetry_json_format_port(telemetry, port_ids[i],
+			ports, metric_ids, num_metric_ids);
+		if (ret < 0) {
+			TELEMETRY_LOG_ERR("Error - format port in JSON "
+				"failed\n");
+			return -1;
+		}
+	}
+
+	root = json_object();
+	if (!root) {
+		TELEMETRY_LOG_ERR("Error - Could not create root JSON "
+			"object\n");
+		goto eperm_fail;
+	}
+
+	ret = json_object_set_new(root, "status_code",
+		json_string("Status OK: 200"));
+	if (ret < 0) {
+		TELEMETRY_LOG_ERR("Error - Status code field cannot be set\n");
+		goto eperm_fail;
+	}
+
+	ret = json_object_set_new(root, "data", ports);
+	if (ret < 0) {
+		TELEMETRY_LOG_ERR("Error - Data field cannot be set\n");
+		goto eperm_fail;
+	}
+
+	*json_buffer = json_dumps(root, JSON_INDENT(2));
+	json_decref(root);
+	return 0;
+
+eperm_fail:
+	ret = rte_telemetry_send_error_response(telemetry, -EPERM);
+	if (ret < 0)
+		TELEMETRY_LOG_ERR("Error - Could not send error\n");
+	return -1;
+
+einval_fail:
+	ret = rte_telemetry_send_error_response(telemetry, -EINVAL);
+	if (ret < 0)
+		TELEMETRY_LOG_ERR("Error - Could not send error\n");
+	return -1;
+}
+
 int32_t
 rte_telemetry_send_ports_stats_values(uint32_t *metric_ids, int num_metric_ids,
 	uint32_t *port_ids, int num_port_ids, struct telemetry_impl *telemetry)
@@ -235,6 +540,13 @@ rte_telemetry_send_ports_stats_values(uint32_t *metric_ids, int num_metric_ids,
 	}
 
 	char *json_buffer = NULL;
+	ret = rte_telemetry_encode_json_format(telemetry, port_ids,
+		num_port_ids, metric_ids, num_metric_ids, &json_buffer);
+	if (ret < 0) {
+		TELEMETRY_LOG_ERR("Error - JSON encode function failed\n");
+		return -1;
+	}
+
 	ret = rte_telemetry_write_to_socket(telemetry, json_buffer);
 	if (ret < 0) {
 		TELEMETRY_LOG_ERR("Error - Could not write to socket\n");
-- 
2.7.4