[PATCH] app/test: rewrite telemetry test in python

[Stephen Hemminger <stephen@networkplumber.org>]

The test_telemetry.sh was failing with test timeout.
This was caused by the overhead of spawning a fresh dpdk-telemetry.py
for every command it walked. With every endpoint queried three times,
that is several hundred Python interpreter startups per run.

Replace the shell script with a python test that opens the telemetry
socket once and issues every command over that single connection.

Each reply is parsed as JSON and checked directly in Python.
This also drops the jq dependency.

Bugzilla ID: 1972
Fixes: 9da71dc4f96e ("test: add test case for scripted telemetry commands")
Cc: stable@dpdk.org

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 app/test/suites/meson.build       |   2 +-
 app/test/suites/test_telemetry.py | 129 ++++++++++++++++++++++++++++++
 app/test/suites/test_telemetry.sh |  30 -------
 3 files changed, 130 insertions(+), 31 deletions(-)
 create mode 100755 app/test/suites/test_telemetry.py
 delete mode 100755 app/test/suites/test_telemetry.sh

diff --git a/app/test/suites/meson.build b/app/test/suites/meson.build
index 786c459c24..ec1de99154 100644
--- a/app/test/suites/meson.build
+++ b/app/test/suites/meson.build
@@ -145,7 +145,7 @@ if not is_windows and dpdk_conf.has('RTE_LIB_TELEMETRY')
         test_args += ['--vdev=rawdev_skeleton0']
     endif
     test_args += ['-a', '0000:00:00.0']
-    test('telemetry_all', find_program('test_telemetry.sh'),
+    test('telemetry_all', find_program('test_telemetry.py'),
             args: test_args,
             timeout : timeout_seconds_fast,
             is_parallel : false,
diff --git a/app/test/suites/test_telemetry.py b/app/test/suites/test_telemetry.py
new file mode 100755
index 0000000000..f37eccabcc
--- /dev/null
+++ b/app/test/suites/test_telemetry.py
@@ -0,0 +1,129 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright (c) 2022 Red Hat, Inc.
+
+"""Exercise every telemetry command exported by an application.
+
+Spawns the DPDK test binary (passed as arguments), waits for its telemetry
+socket to appear, then walks every command reported by "/", calling each one
+with no parameter and with dummy parameters "0" and "z". Every reply is parsed
+as JSON and checked, so a malformed, empty or missing response fails the test
+immediately and names the offending command, rather than relying on a shell
+pipeline not erroring.
+
+A single connection is reused for the whole walk: the previous shell version
+spawned a fresh dpdk-telemetry.py (Python interpreter + new connection) per
+command, which scaled with process-startup cost and timed out under load.
+"""
+
+import json
+import os
+import socket
+import subprocess
+import sys
+import time
+
+SOCKET_NAME = "dpdk_telemetry.v2"
+
+
+def runtime_dir():
+    """DPDK runtime dir for the default 'rte' file-prefix, matching EAL."""
+    run = os.environ.get("RUNTIME_DIRECTORY")
+    if not run:
+        run = (
+            "/var/run"
+            if os.getuid() == 0
+            else os.environ.get("XDG_RUNTIME_DIR", "/tmp")
+        )
+    return os.path.join(run, "dpdk", "rte")
+
+
+def wait_for_socket(path, proc, timeout=10):
+    """Wait for the telemetry socket, failing fast if the app dies first."""
+    deadline = time.time() + timeout
+    while time.time() < deadline:
+        if os.path.exists(path):
+            return
+        if proc.poll() is not None:
+            raise RuntimeError(
+                "application exited (code %d) before telemetry socket appeared"
+                % proc.returncode
+            )
+        time.sleep(0.05)
+    raise RuntimeError("timed out waiting for telemetry socket %s" % path)
+
+
+class TelemetryClient:
+    def __init__(self, path):
+        self.sock = socket.socket(socket.AF_UNIX, socket.SOCK_SEQPACKET)
+        self.sock.connect(path)
+        info = json.loads(self.sock.recv(1024))
+        self.buf_len = info["max_output_len"]
+
+    def command(self, cmd):
+        self.sock.send(cmd.encode())
+        reply = self.sock.recv(self.buf_len).decode()
+        try:
+            return json.loads(reply)
+        except json.JSONDecodeError as e:
+            raise AssertionError(
+                "invalid JSON reply for %r: %s (raw: %r)" % (cmd, e, reply)
+            )
+
+    def close(self):
+        self.sock.close()
+
+
+def check_reply(cmd, reply):
+    """A telemetry reply must be a dict keyed by the command name."""
+    if not isinstance(reply, dict) or list(reply.keys()) != [cmd.split(",")[0]]:
+        raise AssertionError("unexpected reply for %r: %r" % (cmd, reply))
+
+
+def walk(client):
+    listing = client.command("/")
+    check_reply("/", listing)
+    count = 0
+    for cmd in listing["/"]:
+        for arg in ("", ",0", ",z"):
+            full = cmd + arg
+            reply = client.command(full)
+            check_reply(full, reply)
+            count += 1
+    return count
+
+
+def main():
+    if len(sys.argv) < 2:
+        print("usage: %s <dpdk-app> [eal args...]" % sys.argv[0], file=sys.stderr)
+        return 1
+
+    sock_path = os.path.join(runtime_dir(), SOCKET_NAME)
+    proc = subprocess.Popen(sys.argv[1:], stdin=subprocess.PIPE)
+    try:
+        wait_for_socket(sock_path, proc)
+        client = TelemetryClient(sock_path)
+        try:
+            count = walk(client)
+        finally:
+            client.close()
+        print("telemetry: walked %d commands" % count)
+    finally:
+        # tell the interactive prompt to exit, then ensure the app is gone
+        try:
+            proc.stdin.write(b"quit\n")
+            proc.stdin.flush()
+            proc.stdin.close()
+        except (BrokenPipeError, OSError):
+            pass
+        try:
+            proc.wait(timeout=5)
+        except subprocess.TimeoutExpired:
+            proc.terminate()
+            proc.wait()
+
+    return 0 if proc.returncode == 0 else proc.returncode
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/app/test/suites/test_telemetry.sh b/app/test/suites/test_telemetry.sh
deleted file mode 100755
index 3c5b629b63..0000000000
--- a/app/test/suites/test_telemetry.sh
+++ /dev/null
@@ -1,30 +0,0 @@
-#!/bin/sh -e
-# SPDX-License-Identifier: BSD-3-Clause
-# Copyright (c) 2022 Red Hat, Inc.
-
-which jq || {
-    echo "No jq available, skipping test."
-    exit 77
-}
-
-rootdir=$(readlink -f $(dirname $(readlink -f $0))/../../..)
-tmpoutput=$(mktemp -t dpdk.test_telemetry.XXXXXX)
-trap "cat $tmpoutput; rm -f $tmpoutput" EXIT
-
-call_all_telemetry() {
-    telemetry_script=$rootdir/usertools/dpdk-telemetry.py
-    echo >$tmpoutput
-    echo "Telemetry commands log:" >>$tmpoutput
-    echo / | $telemetry_script | jq -r '.["/"][]' | while read cmd
-    do
-        for input in $cmd $cmd,0 $cmd,z
-        do
-            echo Calling $input >> $tmpoutput
-            echo $input | $telemetry_script >> $tmpoutput 2>&1
-        done
-    done
-}
-
-! set -o | grep -q errtrace || set -o errtrace
-! set -o | grep -q pipefail || set -o pipefail
-(sleep 1 && call_all_telemetry && echo quit) | $@
-- 
2.53.0