[dpdk-dev] [PATCH v6 5/5] usertools/dpdk-telemetry: provide info on available sockets

[Bruce Richardson <bruce.richardson@intel.com>]

When a user runs the dpdk-telemetry script and fails to connect because
the socket path does not exist, run a scan for possible sockets that
could be connected to and inform the user of the command needed to
connect to those.

For example, when running the script without any parameters, but there
are DPDK processes running with in-memory mode (so they need to be
identified by PID), the error message will include the details of how to
connect to each process:

  $ ./usertools/dpdk-telemetry.py
  Connecting to /run/user/1000/dpdk/rte/dpdk_telemetry.v2
  Error connecting to /run/user/1000/dpdk/rte/dpdk_telemetry.v2

  Other DPDK telemetry sockets found:
  - dpdk_telemetry.v2.20755  # Connect with './usertools/dpdk-telemetry.py -p 20755'
  - dpdk_telemetry.v2.20451  # Connect with './usertools/dpdk-telemetry.py -p 20451'

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
---
 doc/guides/howto/telemetry.rst |  3 +++
 usertools/dpdk-telemetry.py    | 41 ++++++++++++++++++++++++++++++----
 2 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/doc/guides/howto/telemetry.rst b/doc/guides/howto/telemetry.rst
index c3adca9504..cdde57cb3b 100644
--- a/doc/guides/howto/telemetry.rst
+++ b/doc/guides/howto/telemetry.rst
@@ -68,6 +68,9 @@ and query information using the telemetry client python script.
      When connecting to a process run with `--in-memory` EAL flag,
      one must specify the PID of the process to connect to using the `-p` flag.
      This is because there may be multiple such instances.
+     If there are only *in-memory* DPDK processes to connect to,
+     and no PID, or an invalid PID parameter, is provided,
+     the telemetry script will list any available telemetry sockets and how to connect to them.
 
 #. When connected, the script displays the following, waiting for user input::
 
diff --git a/usertools/dpdk-telemetry.py b/usertools/dpdk-telemetry.py
index 690014ba9a..7f22e21828 100755
--- a/usertools/dpdk-telemetry.py
+++ b/usertools/dpdk-telemetry.py
@@ -10,6 +10,7 @@
 import socket
 import os
 import sys
+import glob
 import json
 import errno
 import readline
@@ -17,6 +18,8 @@
 
 # global vars
 TELEMETRY_VERSION = "v2"
+SOCKET_NAME = 'dpdk_telemetry.{}'.format(TELEMETRY_VERSION)
+DEFAULT_PREFIX = 'rte'
 CMDS = []
 
 
@@ -48,7 +51,28 @@ def get_app_name(pid):
     return None
 
 
-def handle_socket(path):
+def find_sockets(path):
+    """ Find any possible sockets to connect to and return them """
+    return glob.glob(os.path.join(path, SOCKET_NAME + '*'))
+
+
+def print_socket_options(prefix, paths):
+    """ Given a set of socket paths, give the commands needed to connect """
+    cmd = sys.argv[0]
+    if prefix != DEFAULT_PREFIX:
+        cmd += " -f " + prefix
+    for s in paths:
+        sock_name = os.path.basename(s)
+        if sock_name.endswith(TELEMETRY_VERSION):
+            print("- {}  # Connect with '{}'".format(os.path.basename(s),
+                                                     cmd))
+        else:
+            print("- {}  # Connect with '{} -p {}'".format(os.path.basename(s),
+                                                           cmd,
+                                                           s.split('.')[-1]))
+
+
+def handle_socket(args, path):
     """ Connect to socket and handle user input """
     prompt = ''  # this evaluates to false in conditions
     sock = socket.socket(socket.AF_UNIX, socket.SOCK_SEQPACKET)
@@ -62,6 +86,15 @@ def handle_socket(path):
     except OSError:
         print("Error connecting to " + path)
         sock.close()
+        # if socket exists but is bad, or if non-interactive just return
+        if os.path.exists(path) or not prompt:
+            return
+        # if user didn't give a valid socket path, but there are
+        # some sockets, help the user out by printing how to connect
+        socks = find_sockets(os.path.dirname(path))
+        if socks:
+            print("\nOther DPDK telemetry sockets found:")
+            print_socket_options(args.file_prefix, socks)
         return
     json_reply = read_socket(sock, 1024, prompt)
     output_buf_len = json_reply["max_output_len"]
@@ -110,13 +143,13 @@ def get_dpdk_runtime_dir(fp):
 readline.set_completer_delims(readline.get_completer_delims().replace('/', ''))
 
 parser = argparse.ArgumentParser()
-parser.add_argument('-f', '--file-prefix', default='rte',
+parser.add_argument('-f', '--file-prefix', default=DEFAULT_PREFIX,
                     help='Provide file-prefix for DPDK runtime directory')
 parser.add_argument('-p', '--pid',
                     help='Connect to DPDK process with the given pid')
 args = parser.parse_args()
 rd = get_dpdk_runtime_dir(args.file_prefix)
-sock_path = os.path.join(rd, 'dpdk_telemetry.{}'.format(TELEMETRY_VERSION))
+sock_path = os.path.join(rd, SOCKET_NAME)
 if args.pid:
     sock_path += ".{}".format(args.pid)
-handle_socket(sock_path)
+handle_socket(args, sock_path)
-- 
2.30.2