tests: run tests against a running VPP

Usage:
test/run.py -r  -t {test_filter}
Instead of starting a new instance of VPP, when the -r argument
is provided, test is run against a running VPP instance. Optionally,
one can also set the VPP socket directory using the -d
argument. The default location for socket files is
/var/run/user/${uid}/vpp and /var/run/vpp if VPP is started
as root.

Type: improvement

Change-Id: I05e57a067fcb90fb49973f8159fc17925b741f1a
Signed-off-by: Naveen Joy <najoy@cisco.com>

1 files changed, 157 insertions, 0 deletions

diff --git a/test/vpp_running.py b/test/vpp_running.py
new file mode 100644
index 00000000000..e1ffe376546
--- /dev/null
+++ b/test/vpp_running.py
@@ -0,0 +1,157 @@
+#!/usr/bin/env python3
+
+# Supporting module for running tests against a running VPP.
+# This module is used by the test framework. Do not invoke this module
+# directly for running tests against a running vpp. Use run.py for
+# running all unit tests.
+
+from glob import glob
+import os
+import sys
+import subprocess
+from config import config
+
+
+def use_running(cls):
+    """Update VPPTestCase to use running VPP's sock files & methods.
+
+    Arguments:
+    cls -- VPPTestCase Class
+    """
+    if config.running_vpp:
+        if os.path.isdir(config.socket_dir):
+            RunningVPP.socket_dir = config.socket_dir
+        else:
+            RunningVPP.socket_dir = RunningVPP.get_default_socket_dir()
+        RunningVPP.get_set_vpp_sock_files()
+        cls.get_stats_sock_path = RunningVPP.get_stats_sock_path
+        cls.get_api_sock_path = RunningVPP.get_api_sock_path
+        cls.run_vpp = RunningVPP.run_vpp
+        cls.quit_vpp = RunningVPP.quit_vpp
+        cls.vpp = RunningVPP
+        cls.running_vpp = True
+    return cls
+
+
+class RunningVPP:
+
+    api_sock = ""  # api_sock file path
+    stats_sock = ""  # stats sock_file path
+    socket_dir = ""  # running VPP's socket directory
+    pid = None  # running VPP's pid
+    returncode = None  # indicates to the framework that VPP is running
+
+    @classmethod
+    def get_stats_sock_path(cls):
+        return cls.stats_sock
+
+    @classmethod
+    def get_api_sock_path(cls):
+        return cls.api_sock
+
+    @classmethod
+    def run_vpp(cls):
+        """VPP is already running -- skip this action."""
+        pass
+
+    @classmethod
+    def quit_vpp(cls):
+        """Indicate quitting to framework by setting returncode=1."""
+        cls.returncode = 1
+
+    @classmethod
+    def terminate(cls):
+        """Indicate termination to framework by setting returncode=1."""
+        cls.returncode = 1
+
+    @classmethod
+    def get_default_socket_dir(cls):
+        """Return running VPP's default socket directory.
+
+        Default socket dir is:
+           /var/run/user/${UID}/vpp  (or)
+           /var/run/vpp, if VPP is started as a root user
+        """
+        if cls.is_running_vpp():
+            vpp_user_id = (
+                subprocess.check_output(["ps", "-o", "uid=", "-p", str(cls.pid)])
+                .decode("utf-8")
+                .strip()
+            )
+            if vpp_user_id == "0":
+                return "/var/run/vpp"
+            else:
+                return f"/var/run/user/{vpp_user_id}/vpp"
+        else:
+            print(
+                "Error: getting default socket dir, as "
+                "a running VPP process could not be found"
+            )
+            sys.exit(1)
+
+    @classmethod
+    def get_set_vpp_sock_files(cls):
+        """Look for *.sock files in the socket_dir and set cls attributes.
+
+        Returns a tuple: (api_sock_file, stats_sock_file)
+        Sets cls.api_sock and cls.stats_sock attributes
+        """
+        # Return if the sock files are already set
+        if cls.api_sock and cls.stats_sock:
+            return (cls.api_sock, cls.stats_sock)
+        # Find running VPP's sock files in the socket dir
+        if os.path.isdir(cls.socket_dir):
+            if not cls.is_running_vpp():
+                print(
+                    "Error: The socket dir for a running VPP directory is, "
+                    "set but a running VPP process could not be found"
+                )
+                sys.exit(1)
+            sock_files = glob(os.path.join(cls.socket_dir + "/" + "*.sock"))
+            for sock_file in sock_files:
+                if "api.sock" in sock_file:
+                    cls.api_sock = os.path.abspath(sock_file)
+                elif "stats.sock" in sock_file:
+                    cls.stats_sock = os.path.abspath(sock_file)
+            if not cls.api_sock:
+                print(
+                    f"Error: Could not find a valid api.sock file "
+                    f"in running VPP's socket directory {cls.socket_dir}"
+                )
+                sys.exit(1)
+            if not cls.stats_sock:
+                print(
+                    f"Error: Could not find a valid stats.sock file "
+                    f"in running VPP's socket directory {cls.socket_dir}"
+                )
+                sys.exit(1)
+            return (cls.api_sock, cls.stats_sock)
+        else:
+            print("Error: The socket dir for a running VPP directory is unset")
+            sys.exit(1)
+
+    @classmethod
+    def is_running_vpp(cls):
+        """Return True if VPP's pid is visible else False."""
+        vpp_pid = subprocess.Popen(
+            ["pgrep", "-d,", "-x", "vpp_main"],
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            universal_newlines=True,
+        )
+        stdout, stderr = vpp_pid.communicate()
+        cls.pid = int(stdout.split(",")[0]) if stdout else None
+        return bool(cls.pid)
+
+    @classmethod
+    def poll(cls):
+        """Return None to indicate that the process hasn't terminated."""
+        return cls.returncode
+
+
+if __name__ == "__main__":
+    RunningVPP.socket_dir = RunningVPP.get_default_socket_dir()
+    RunningVPP.get_set_vpp_sock_files()
+    print(f"Running VPP's sock files")
+    print(f"api_sock_file {RunningVPP.api_sock}")
+    print(f"stats_sock_file {RunningVPP.stats_sock}")