Implement PCP metrics channel

Co-Authored-By: Allison Karlitskaya <allison.karlitskaya@redhat.com>
Co-Authored-By: Tomas Matus <tomatus777@gmail.com>

pyproject.toml

@@ -31,6 +31,10 @@ module = [
     "libvirt_qemu",
     "pika",
 
+    # run without pcp module types
+    "pcp",
+    "cpmapi",
+
     # run without gobject-introspection (used from cockpit-client for Gtk)
     "gi.*",
 
@@ -193,6 +197,7 @@ wheel_build_env = pkg
 # All other environments (names like py311-lint, py36-pytest, etc) are isolated
 # from the system and get their packages from PyPI, according to the specific
 # test environment being requested.  We build the wheel in a common environment.
+# Skip PCP as the PyPi package provides no wheel, requires compilation and is outdated (5.0)
 [testenv]
 package = wheel
 wheel_build_env = venv-pkg
@@ -208,6 +213,6 @@ deps =
   pytest: pytest-xdist
 allowlist_externals = test/static-code
 commands =
-  pytest: python3 -m pytest -opythonpath= {posargs}
+  pytest: python3 -m pytest -k 'not pcp' -opythonpath= {posargs}
   lint: test/static-code --tap
 """

src/cockpit/channels/__init__.py

@@ -20,6 +20,7 @@
 from .http import HttpChannel
 from .metrics import InternalMetricsChannel
 from .packages import PackagesChannel
+from .pcp import PcpMetricsChannel
 from .stream import SocketStreamChannel, SubprocessStreamChannel
 from .trivial import EchoChannel, NullChannel
 
@@ -35,6 +36,7 @@
     InternalMetricsChannel,
     NullChannel,
     PackagesChannel,
+    PcpMetricsChannel,
     SubprocessStreamChannel,
     SocketStreamChannel,
 ]