STATS: Python binding to access VPP statistics and counters.

from vpp_papi.vpp_stats import VPPStats
s = VPPStats(socketname='/var/run/stats.sock')
c = s.ls('/if/rx')
counters = s.dump(c)
print(s.set_error_str())

Change-Id: I203ebe60b0c9ee5742aadc737c0f29051757959d
Signed-off-by: Ole Troan <ot@cisco.com>
diff --git a/src/vpp-api/python/vpp_papi/vpp_stats.py b/src/vpp-api/python/vpp_papi/vpp_stats.py
new file mode 100644
index 0000000..b84a0e5
--- /dev/null
+++ b/src/vpp-api/python/vpp_papi/vpp_stats.py
@@ -0,0 +1,161 @@
+#!/usr/bin/env python
+
+from __future__ import print_function
+from cffi import FFI
+
+ffi = FFI()
+ffi.cdef("""
+typedef uint64_t counter_t;
+typedef struct {
+  counter_t packets;
+  counter_t bytes;
+} vlib_counter_t;
+
+typedef enum {
+  STAT_DIR_TYPE_ILLEGAL = 0,
+  STAT_DIR_TYPE_SCALAR_POINTER,
+  STAT_DIR_TYPE_VECTOR_POINTER,
+  STAT_DIR_TYPE_COUNTER_VECTOR_SIMPLE,
+  STAT_DIR_TYPE_COUNTER_VECTOR_COMBINED,
+  STAT_DIR_TYPE_ERROR_INDEX,
+  STAT_DIR_TYPE_SERIALIZED_NODES,
+} stat_directory_type_t;
+
+typedef struct {
+  stat_directory_type_t type;
+  void *value;
+} stat_segment_directory_entry_t;
+
+typedef struct {
+  char *name;
+  stat_directory_type_t type;
+  union {
+    double scalar_value;
+    uint64_t error_value;
+    uint64_t *vector_pointer;
+    counter_t **simple_counter_vec;
+    vlib_counter_t **combined_counter_vec;
+  };
+} stat_segment_data_t;
+
+typedef struct {
+  char *name;
+  stat_segment_directory_entry_t *ep;
+} stat_segment_cached_pointer_t;
+
+int stat_segment_connect (char *socket_name);
+void stat_segment_disconnect (void);
+
+uint8_t  **stat_segment_ls (uint8_t **pattern);
+stat_segment_data_t *stat_segment_dump (uint8_t ** counter_vec);
+/* Collects registered counters */
+stat_segment_cached_pointer_t *stat_segment_register (uint8_t ** counter_vec);
+stat_segment_data_t *stat_segment_collect (stat_segment_cached_pointer_t *);
+void stat_segment_data_free (stat_segment_data_t * res);
+double stat_segment_heartbeat (void);
+int stat_segment_vec_len(void *vec);
+uint8_t **stat_segment_string_vector(uint8_t **string_vector, char *string);
+""")
+
+
+# Utility functions
+def make_string_vector(api, strings):
+    vec = ffi.NULL
+    if type(strings) is not list:
+        strings = [strings]
+    for s in strings:
+        vec = api.stat_segment_string_vector(vec, ffi.new("char []", s))
+    return vec
+
+
+def make_string_list(api, vec):
+    vec_len = api.stat_segment_vec_len(vec)
+    return [ffi.string(vec[i]) for i in range(vec_len)]
+
+
+# 2-dimensonal array of thread, index
+def simple_counter_vec_list(api, e):
+    vec = []
+    for thread in range(api.stat_segment_vec_len(e)):
+        len_interfaces = api.stat_segment_vec_len(e[thread])
+        if_per_thread = [e[thread][interfaces]
+                         for interfaces in range(len_interfaces)]
+        vec.append(if_per_thread)
+    return vec
+
+
+def vlib_counter_dict(c):
+    return {'packets': c.packets,
+            'bytes': c.bytes}
+
+
+def combined_counter_vec_list(api, e):
+    vec = []
+    for thread in range(api.stat_segment_vec_len(e)):
+        len_interfaces = api.stat_segment_vec_len(e[thread])
+        if_per_thread = [vlib_counter_dict(e[thread][interfaces])
+                         for interfaces in range(len_interfaces)]
+        vec.append(if_per_thread)
+    return vec
+
+
+def stat_entry_to_python(api, e):
+    if e.type == 3:
+        return simple_counter_vec_list(e.simple_counter_vec)
+    if e.type == 4:
+        return combined_counter_vec_list(api, e.combined_counter_vec)
+    if e.type == 5:
+        return e.error_value
+    return None
+
+
+class VPPStats:
+    def __init__(self, socketname='/var/run/stats.sock'):
+        self.api = ffi.dlopen('libvppapiclient.so')
+        rv = self.api.stat_segment_connect(socketname)
+        if rv != 0:
+            raise IOError()
+
+    def heartbeat(self):
+        return self.api.stat_segment_heartbeat()
+
+    def ls(self, patterns):
+        return self.api.stat_segment_ls(make_string_vector(self.api, patterns))
+
+    def dump(self, counters):
+        stats = {}
+        rv = self.api.stat_segment_dump(counters)
+        rv_len = self.api.stat_segment_vec_len(rv)
+        for i in range(rv_len):
+            n = ffi.string(rv[i].name)
+            e = stat_entry_to_python(self.api, rv[i])
+            if e:
+                stats[n] = e
+        return stats
+
+    def dump_str(self, counters_str):
+        return self.dump(make_string_vector(self.api, counters_str))
+
+    def disconnect(self):
+        self.api.stat_segment_disconnect()
+
+    def set_errors(self):
+        '''Return all errors counters > 0'''
+        error_names = self.ls(['/err/'])
+        error_counters = self.dump(error_names)
+        return {k: error_counters[k]
+                for k in error_counters.keys() if error_counters[k]}
+
+    def set_errors_str(self):
+        '''Return all errors counters > 0 pretty printed'''
+        s = 'ERRORS:\n'
+        error_counters = self.set_errors()
+        for k in sorted(error_counters):
+            s += '{:<60}{:>10}\n'.format(k, error_counters[k])
+        return s
+
+    def register(self):
+        raise NotImplemented
+
+    def collect(self):
+        raise NotImplemented