WIP: Expose read-write and read-only endpoints when related to data-integrator

Author: shayancanonical

charmcraft.yaml

@@ -27,6 +27,12 @@ parts:
           echo 'ERROR: Use "tox run -e build" instead of calling "charmcraft pack" directly' >&2
           exit 1
       fi
+    build-packages:
+      - libffi-dev
+      - libssl-dev
+      - pkg-config
+      - rustc
+      - cargo
     charm-entrypoint: src/machine_charm.py
     prime:
       - charm_version

lib/charms/tls_certificates_interface/v2/tls_certificates.py

@@ -38,6 +38,10 @@ requires:
   juju-info:
     interface: juju-info
     scope: container
+  certificates:
+    interface: tls-certificates
+    optional: true
+    limit: 1
 peers:
   cos:
     interface: cos

metadata.yaml

@@ -18,6 +18,9 @@ jinja2 = "^3.1.2"
 [tool.poetry.group.charm-libs.dependencies]
 # data_platform_libs/v0/data_interfaces.py
 ops = ">=2.0.0"
+# tls_certificates_interface/v1/tls_certificates.py
+cryptography = "*"
+jsonschema = "*"
 # grafana_agent/v0/cos_agent.py
 pydantic = "<2"
 cosl = "*"

poetry.lock

@@ -116,6 +116,9 @@ def _tls_certificate(self) -> str:
         # TODO VM TLS: Update property after implementing TLS on machine_charm
         return None
 
+    def is_exposed(self, relation=None) -> bool:
+        return self._database_provides.is_exposed(relation)
+
     def _cos_exporter_config(self, event) -> typing.Optional[relations.cos.ExporterConfig]:
         """Returns the exporter config for MySQLRouter exporter if cos relation exists"""
         cos_relation_exists = self._cos.relation_exists and not self._cos.is_relation_breaking(

pyproject.toml

@@ -27,6 +27,9 @@
 class MachineSubordinateRouterCharm(abstract_charm.MySQLRouterCharm):
     """MySQL Router machine subordinate charm"""
 
+    READ_WRITE_PORT = 6446
+    READ_ONLY_PORT = 6447
+
     def __init__(self, *args) -> None:
         super().__init__(*args)
         # DEPRECATED shared-db: Enable legacy "mysql-shared" interface
@@ -67,12 +70,21 @@ def _logrotate(self) -> machine_logrotate.LogRotate:
     def _cos(self) -> relations.cos.COSRelation:
         return self._cos_relation
 
+    @property
+    def _host_address(self) -> str:
+        """The host address for the machine."""
+        return self.model.get_binding(upgrade.PEER_RELATION_ENDPOINT_NAME).network.bind_address
+
     @property
     def _read_write_endpoint(self) -> str:
+        if self._database_provides.is_exposed():
+            return f"{self._host_address}:{self.READ_WRITE_PORT}"
         return f'file://{self._container.path("/run/mysqlrouter/mysql.sock")}'
 
     @property
     def _read_only_endpoint(self) -> str:
+        if self._database_provides.is_exposed():
+            return f"{self._host_address}:{self.READ_ONLY_PORT}"
         return f'file://{self._container.path("/run/mysqlrouter/mysqlro.sock")}'
 
     # =======================
@@ -119,6 +131,10 @@ def _on_force_upgrade_action(self, event: ops.ActionEvent) -> None:
         event.set_results({"result": f"Forcefully upgraded {self.unit.name}"})
         logger.debug("Forced upgrade")
 
+    def reconcile(self, event=None) -> None:
+        self.database_provides.reconcile_ports()
+        super().reconcile(event=event)
+
 
 if __name__ == "__main__":
     ops.main.main(MachineSubordinateRouterCharm)

src/abstract_charm.py

@@ -38,6 +38,14 @@ def __init__(
             charm_
         )
 
+    def is_exposed(self, _) -> bool:
+        """Whether the relation is exposed"""
+        return self._database_provides.is_exposed()
+
+    def reconcile_ports(self) -> None:
+        """Reconcile ports for this unit"""
+        self._database_provides.reconcile_ports()
+
     def reconcile_users(
         self,
         *,

src/machine_charm.py

@@ -162,6 +162,8 @@ class RelationEndpoint:
 
     def __init__(self, charm_: "abstract_charm.MySQLRouterCharm") -> None:
         self._interface = data_interfaces.DatabaseProvides(charm_, relation_name=self._NAME)
+        self._charm = charm_
+
         charm_.framework.observe(charm_.on[self._NAME].relation_created, charm_.reconcile)
         charm_.framework.observe(self._interface.on.database_requested, charm_.reconcile)
         charm_.framework.observe(charm_.on[self._NAME].relation_broken, charm_.reconcile)
@@ -179,6 +181,21 @@ def _shared_users(self) -> typing.List[_RelationWithSharedUser]:
                 pass
         return shared_users
 
+    def is_exposed(self) -> bool:
+        """Whether the relation is exposed."""
+        relation_data = self._interface.fetch_relation_data(fields=["external-node-connectivity"])
+        return any(
+            [data.get("external-node-connectivity") == "true" for data in relation_data.values()]
+        )
+
+    def reconcile_ports(self) -> None:
+        """Reconcile ports for this unit"""
+        if self.is_exposed():
+            ports = [self._charm.READ_WRITE_PORT, self._charm.READ_ONLY_PORT]
+        else:
+            ports = []
+        self._charm.unit.set_ports(ports)
+
     def reconcile_users(
         self,
         *,

src/relations/database_providers_wrapper.py

@@ -20,10 +20,11 @@ class AuthenticatedSocketWorkload(workload.AuthenticatedWorkload):
     # TODO python3.10 min version: Use `list` instead of `typing.List`
     def _get_bootstrap_command(self, password: str) -> typing.List[str]:
         command = super()._get_bootstrap_command(password)
+        bind_address = "0.0.0.0" if self._charm._database_provides.is_exposed() else "127.0.0.1"
         command.extend(
             [
                 "--conf-bind-address",
-                "127.0.0.1",
+                bind_address,
                 "--conf-use-sockets",
                 # For unix sockets, authentication fails on first connection if this option is not
                 # set. Workaround for https://bugs.mysql.com/bug.php?id=107291