[dpdk-dev] [RFC 1/2] telemetry: support some recursive data objects

[Ciara Power <ciara.power@intel.com>]

Dict data objects now support uint64_t array data object values.
Only one level of recursion supported.

Signed-off-by: Ciara Power <ciara.power@intel.com>
---
 lib/librte_telemetry/rte_telemetry.h          | 27 +++++++++++++++
 .../rte_telemetry_version.map                 |  2 ++
 lib/librte_telemetry/telemetry.c              | 34 +++++++++++++++++++
 lib/librte_telemetry/telemetry_data.c         | 18 ++++++++++
 lib/librte_telemetry/telemetry_data.h         |  3 ++
 lib/librte_telemetry/telemetry_json.h         | 17 ++++++++++
 6 files changed, 101 insertions(+)

diff --git a/lib/librte_telemetry/rte_telemetry.h b/lib/librte_telemetry/rte_telemetry.h
index 2c3c96cf7..dc18c34d0 100644
--- a/lib/librte_telemetry/rte_telemetry.h
+++ b/lib/librte_telemetry/rte_telemetry.h
@@ -44,6 +44,7 @@ enum rte_tel_value_type {
 	RTE_TEL_STRING_VAL, /** a string value */
 	RTE_TEL_INT_VAL,    /** a signed 32-bit int value */
 	RTE_TEL_U64_VAL,    /** an unsigned 64-bit int value */
+	RTE_TEL_DATA_VAL,   /** a rte_tel_data pointer value */
 };
 
 /**
@@ -188,6 +189,22 @@ int
 rte_tel_data_add_dict_u64(struct rte_tel_data *d,
 		const char *name, uint64_t val);
 
+/**
+ * Add a data object pointer to a dictionary.
+ * The dict must have been started by rte_tel_data_start_dict().
+ *
+ * @param d
+ *   The data structure passed to the callback
+ * @param x
+ *   The data pointer to be returned in the dictionary
+ * @return
+ *   0 on success, negative errno on error
+ */
+__rte_experimental
+int
+rte_tel_data_add_dict_data(struct rte_tel_data *d, const char *name,
+		struct rte_tel_data *val);
+
 /**
  * This telemetry callback is used when registering a telemetry command.
  * It handles getting and formatting information to be returned to telemetry
@@ -253,4 +270,14 @@ int
 rte_telemetry_init(const char *runtime_dir, rte_cpuset_t *cpuset,
 		const char **err_str);
 
+/**
+ * Get the size of the rte_tel_data struct.
+ *
+ * @return
+ *  size_t of the struct
+ */
+__rte_experimental
+size_t
+rte_tel_get_data_size(void);
+
 #endif
diff --git a/lib/librte_telemetry/rte_telemetry_version.map b/lib/librte_telemetry/rte_telemetry_version.map
index 86433c21d..c5425eff6 100644
--- a/lib/librte_telemetry/rte_telemetry_version.map
+++ b/lib/librte_telemetry/rte_telemetry_version.map
@@ -4,6 +4,7 @@ EXPERIMENTAL {
 	rte_tel_data_add_array_int;
 	rte_tel_data_add_array_string;
 	rte_tel_data_add_array_u64;
+	rte_tel_data_add_dict_data;
 	rte_tel_data_add_dict_int;
 	rte_tel_data_add_dict_string;
 	rte_tel_data_add_dict_u64;
@@ -13,6 +14,7 @@ EXPERIMENTAL {
 	rte_telemetry_init;
 	rte_telemetry_legacy_register;
 	rte_telemetry_register_cmd;
+	rte_tel_get_data_size;
 
 	local: *;
 };
diff --git a/lib/librte_telemetry/telemetry.c b/lib/librte_telemetry/telemetry.c
index 7b6f8a79e..b3a5f4296 100644
--- a/lib/librte_telemetry/telemetry.c
+++ b/lib/librte_telemetry/telemetry.c
@@ -47,6 +47,12 @@ static int num_callbacks; /* How many commands are registered */
 /* Used when accessing or modifying list of command callbacks */
 static rte_spinlock_t callback_sl = RTE_SPINLOCK_INITIALIZER;
 
+size_t
+rte_tel_get_data_size(void)
+{
+	return DATA_STRUCT_SIZE;
+}
+
 int
 rte_telemetry_register_cmd(const char *cmd, telemetry_cb fn, const char *help)
 {
@@ -120,6 +126,23 @@ command_help(const char *cmd __rte_unused, const char *params,
 	return 0;
 }
 
+static int
+recursive_data_json(const struct rte_tel_data *d, char *out_buf, size_t buf_len)
+{
+	size_t used = 0;
+	unsigned int i;
+
+	if (d->type != RTE_TEL_ARRAY_U64)
+		return snprintf(out_buf, buf_len, "null");
+
+	used = rte_tel_json_empty_array(out_buf, buf_len, 0);
+	for (i = 0; i < d->data_len; i++)
+		used = rte_tel_json_add_array_u64(out_buf,
+				buf_len, used,
+				d->data.array[i].u64val);
+	return used;
+}
+
 static void
 output_json(const char *cmd, const struct rte_tel_data *d, int s)
 {
@@ -166,6 +189,17 @@ output_json(const char *cmd, const struct rte_tel_data *d, int s)
 						buf_len, used,
 						v->name, v->value.u64val);
 				break;
+			case RTE_TEL_DATA_VAL:
+			{
+				char temp[buf_len];
+				if (recursive_data_json(v->value.dataval,
+						temp, buf_len) != 0)
+					used = rte_tel_json_add_obj_json(
+							cb_data_buf,
+							buf_len, used,
+							v->name, temp);
+				free(v->value.dataval);
+			}
 			}
 		}
 		used += prefix_used;
diff --git a/lib/librte_telemetry/telemetry_data.c b/lib/librte_telemetry/telemetry_data.c
index f424bbd48..46ce7f9b0 100644
--- a/lib/librte_telemetry/telemetry_data.c
+++ b/lib/librte_telemetry/telemetry_data.c
@@ -128,3 +128,21 @@ rte_tel_data_add_dict_u64(struct rte_tel_data *d,
 	const size_t bytes = strlcpy(e->name, name, RTE_TEL_MAX_STRING_LEN);
 	return bytes < RTE_TEL_MAX_STRING_LEN ? 0 : E2BIG;
 }
+
+int
+rte_tel_data_add_dict_data(struct rte_tel_data *d, const char *name,
+		struct rte_tel_data *val)
+{
+	struct tel_dict_entry *e = &d->data.dict[d->data_len];
+
+	if (d->type != RTE_TEL_DICT)
+		return -EINVAL;
+	if (d->data_len >= RTE_TEL_MAX_DICT_ENTRIES)
+		return -ENOSPC;
+
+	d->data_len++;
+	e->type = RTE_TEL_DATA_VAL;
+	e->value.dataval = val;
+	const size_t bytes = strlcpy(e->name, name, RTE_TEL_MAX_STRING_LEN);
+	return bytes < RTE_TEL_MAX_STRING_LEN ? 0 : E2BIG;
+}
diff --git a/lib/librte_telemetry/telemetry_data.h b/lib/librte_telemetry/telemetry_data.h
index ff3a371a3..226d961e0 100644
--- a/lib/librte_telemetry/telemetry_data.h
+++ b/lib/librte_telemetry/telemetry_data.h
@@ -8,6 +8,8 @@
 #include <inttypes.h>
 #include "rte_telemetry.h"
 
+#define DATA_STRUCT_SIZE sizeof(struct rte_tel_data)
+
 enum tel_container_types {
 	RTE_TEL_NULL,	      /** null, used as error value */
 	RTE_TEL_STRING,	      /** basic string type, no included data */
@@ -25,6 +27,7 @@ union tel_value {
 	char sval[RTE_TEL_MAX_STRING_LEN];
 	int ival;
 	uint64_t u64val;
+	struct rte_tel_data *dataval;
 };
 
 struct tel_dict_entry {
diff --git a/lib/librte_telemetry/telemetry_json.h b/lib/librte_telemetry/telemetry_json.h
index a2ce4899e..415cfe7c6 100644
--- a/lib/librte_telemetry/telemetry_json.h
+++ b/lib/librte_telemetry/telemetry_json.h
@@ -155,4 +155,21 @@ rte_tel_json_add_obj_str(char *buf, const int len, const int used,
 	return ret == 0 ? used : end + ret;
 }
 
+/**
+ * Add a new element with raw JSON value to the JSON object stored in the
+ * provided buffer.
+ */
+static inline int
+rte_tel_json_add_obj_json(char *buf, const int len, const int used,
+		const char *name, const char *val)
+{
+	int ret, end = used - 1;
+	if (used <= 2) /* assume empty, since minimum is '{}' */
+		return __json_snprintf(buf, len, "{\"%s\":%s}", name, val);
+
+	ret = __json_snprintf(buf + end, len - end, ",\"%s\":%s}",
+			name, val);
+	return ret == 0 ? used : end + ret;
+}
+
 #endif /*_RTE_TELEMETRY_JSON_H_*/
-- 
2.17.1