pants-plugins/uses_services: prepare to allow alternative st2cluster hosts/ports

In the uses_services plugin, I am now adding env var support
(in several PRs), but so far I've avoiding parsing conf files.

Plus, allowing reconfiguration of the st2cluster hosts/ports
would require the st2client and st2 dev cluster config to align.

Today, the st2cluster integration tests hardcode st2client's
base_url to `http://127.0.0.1`. Technically someone could override
the endpoint URLs with ST2_{AUTH,API,STREAM}_URL env vars, but
they would also need to make sure whatever cluster they use
has the examples pack and other things handled by `launchdev.sh`.

Today, the other alternative for using a different cluster would
be to forward the service ports to the localhost at the standard
ports.

For now, just use a separate host for each endpoint so it is
easier to support overriding via env vars and/or conf files
at some point in the future--if someone needs that. Until then,
we'll go with the minimal implementation that assumes the
default hosts and ports.

Author: cognifloyd

pants-plugins/uses_services/scripts/is_st2cluster_running.py

@@ -19,14 +19,14 @@
 from contextlib import closing
 
 
-def _is_st2cluster_running(host: str, ports: list[str]) -> bool:
+def _is_st2cluster_running(endpoints: list[tuple[str, str]]) -> bool:
     """Check for listening ports of st2auth, st2api, and st2stream services.
 
     This should not import the st2 code as it should be self-contained.
     """
     # TODO: Once each service gains a reliable health check endpoint, use that.
     # https://github.com/StackStorm/st2/issues/4020
-    for port in ports:
+    for host, port in endpoints:
         # based on https://stackoverflow.com/a/35370008/1134951
         with closing(socket.socket(socket.AF_INET, socket.SOCK_STREAM)) as sock:
             # errno=0 means the connection succeeded
@@ -37,12 +37,16 @@ def _is_st2cluster_running(host: str, ports: list[str]) -> bool:
 
 
 if __name__ == "__main__":
-    hostname = "127.0.0.1"
-    service_ports = list(sys.argv[1:])
-    if not service_ports:
-        # st2.tests*.conf ends in /, but the default ends in //
-        service_ports = ["9100", "9101", "9102"]
-
-    is_running = _is_st2cluster_running(hostname, service_ports)
+    args_iter = iter(sys.argv[1:])
+    # Turn the list into 2 tuples (zip with query the same iterator twice for each entry)
+    endpoints = list(zip(args_iter, args_iter))
+    if not endpoints:
+        endpoints = [
+            ("127.0.0.1", "9100"),
+            ("127.0.0.1", "9101"),
+            ("127.0.0.1", "9102"),
+        ]
+
+    is_running = _is_st2cluster_running(endpoints)
     exit_code = 0 if is_running else 1
     sys.exit(exit_code)

pants-plugins/uses_services/st2cluster_rules.py

@@ -46,13 +46,36 @@
 class UsesSt2ClusterRequest:
     """One or more targets need a running st2 cluster with all st2* services."""
 
+    auth_host: str = "127.0.0.1"
     auth_port: int = 9100
+    api_host: str = "127.0.0.1"
     api_port: int = 9101
+    stream_host: str = "127.0.0.1"
     stream_port: int = 9102
 
     @property
-    def ports(self) -> tuple[str, ...]:
-        return str(self.auth_port), str(self.api_port), str(self.stream_port)
+    def endpoints(self) -> tuple[tuple[str, str], ...]:
+        return (
+            (self.auth_host, str(self.auth_port)),
+            (self.api_host, str(self.api_port)),
+            (self.stream_host, str(self.stream_port)),
+        )
+
+    # @classmethod
+    # def from_env(cls, env: EnvironmentVars) -> UsesSt2ClusterRequest:
+    #    return cls()
+    # TODO: consider adding a from_env method using one or both of client => server vars:
+    #   ST2_CONFIG_FILE => ST2_CONFIG_PATH (used by many tests, so not safe) or
+    #                      ST2_CONF (only in launchdev.sh and st2ctl)
+    #   ST2_BASE_URL    => ST2_WEBUI__WEBUI_BASE_URL
+    #   ST2_API_URL     => ST2_AUTH__API_URL or
+    #                      http{'s' if ST2_API__USE_SSL else ''}://{ST2_API__HOST}:{ST2_API__PORT}
+    #   ST2_AUTH_URL    => http://{ST2_AUTH__HOST}:{ST2_AUTH__PORT}
+    #   ST2_STREAM_URL  => http://{ST2_STREAM__HOST}:{ST2_STREAM__PORT}
+    #   ST2_CACERT (might be needed if using a self-signed cert) => n/a
+    # These st2client env vars are irrelevant for the connectivity check:
+    #   ST2_AUTH_TOKEN or ST2_API_KEY
+    #   ST2_API_VERSION (always "v1" since we don't have anything else)
 
 
 @dataclass(frozen=True)
@@ -113,7 +136,11 @@ async def st2cluster_is_running(
         FallibleProcessResult,
         VenvPexProcess(
             script_pex,
-            argv=request.ports,
+            argv=[
+                host_or_port
+                for endpoint in request.endpoints
+                for host_or_port in endpoint
+            ],
             input_digest=script_digest,
             description="Checking to see if ST2 Cluster is up and accessible.",
             # this can change from run to run, so don't cache results.