Merge pull request #3 from mkalcok/ssh-connector

Ssh connector

Author: mkalcok

README.md

@@ -195,8 +195,12 @@ Press 'Enter' to rebuild and deploy OVN. (Ctrl-C for exit)
 ## Supported remote connectors
 
 This tool is primarily meant to sync OVN binaries to the remote hosts running the
-cluster. Following connectors are currently supported:
-  * LXD
+cluster. It supports multiple types of connection types called "Connectors". Each
+connector has specific syntax for defining remote targets expected in  the `-H/--host`
+argument. Following connectors are currently supported:
+
+  * LXD - `lxd:<container_name>`
+  * SSH - `ssh:[<username>@]<hostname_or_ip>`
 
 ## Caveats
 
@@ -250,7 +254,6 @@ Note that this command may "fail" if the coverage is not sufficient.
 * Support execution of arbitrary scripts aside from just restarting services on file
   updates. This will enable syncing things like OVSDB schemas as they require migration
   execution of a migration script instead of just a service restart.
-* Add SSH connector
 * Add automation for bootstrapping local OVN source repository
 * Add automation for bootstrap remote cluster
 * Add command that lists supported remote connectors

microovn_rebuilder/cli.py

@@ -59,6 +59,7 @@ def watch(
                 print("[local] No changes in watched files")
         except KeyboardInterrupt:
             print()
+            connector.teardown()
             break
 
 
@@ -81,10 +82,13 @@ def parse_args() -> argparse.Namespace:  # pragma: no cover
     )
     parser.add_argument(
         "-H",
-        "--host",
+        "--hosts",
         type=str,
         required=True,
-        help="Remote host specification. Expected format: '<connection_type>:<remote_host>'",
+        help="Comma-separated list of remote host to which changes will be synced. For "
+        "details on supported connectors and their syntax, please see "
+        "documentation. Generally, the format is:"
+        "'<connection_type>:<remote_host>'",
     )
     parser.add_argument(
         "-j",
@@ -106,7 +110,7 @@ def main() -> None:
         sys.exit(1)
 
     try:
-        connector = create_connector(args.host)
+        connector = create_connector(args.hosts)
         connector.check_remote(args.remote_path)
     except ConnectorException as exc:
         print(f"Failed to create connection to remote host: {exc}")

microovn_rebuilder/remote/__init__.py

@@ -1,7 +1,11 @@
 from .base import BaseConnector, ConnectorException
 from .lxd import LXDConnector
+from .ssh import SSHConnector
 
-_CONNECTORS = {"lxd": LXDConnector}
+_CONNECTORS = {
+    "lxd": LXDConnector,
+    "ssh": SSHConnector,
+}
 
 
 def create_connector(remote_spec: str) -> BaseConnector:
@@ -23,10 +27,13 @@ def create_connector(remote_spec: str) -> BaseConnector:
         )
 
     connector_type = types.pop()
-    connector = _CONNECTORS.get(connector_type)
-    if connector is None:
+    connector_class = _CONNECTORS.get(connector_type)
+    if connector_class is None:
         raise ConnectorException(
             f"{connector_type} is not a valid connector type. Available types: {", ".join(_CONNECTORS.keys())}"
         )
 
-    return connector(remotes)
+    connector = connector_class(remotes)
+    connector.initialize()
+
+    return connector

microovn_rebuilder/remote/base.py

@@ -13,6 +13,14 @@ class BaseConnector(ABC):
     def __init__(self, remotes: List[str]) -> None:
         self.remotes = remotes
 
+    @abstractmethod
+    def initialize(self) -> None:
+        pass  # pragma: no cover
+
+    @abstractmethod
+    def teardown(self) -> None:
+        pass  # pragma: no cover
+
     @abstractmethod
     def check_remote(self, remote_dst: str) -> None:
         pass  # pragma: no cover

microovn_rebuilder/remote/lxd.py

@@ -10,6 +10,14 @@
 
 class LXDConnector(BaseConnector):
 
+    def initialize(self) -> None:
+        # LXDConnector does not require any special initialization
+        pass  # pragma: no cover
+
+    def teardown(self) -> None:
+        # LXDConnector does not require any special teardown
+        pass  # pragma: no cover
+
     def update(self, target: Target) -> None:
         for remote in self.remotes:
             print(f"{os.linesep}[{remote}] Removing remote file {target.remote_path}")

microovn_rebuilder/remote/ssh.py

@@ -0,0 +1,77 @@
+import os
+from typing import Dict, List
+
+from paramiko import SSHClient, SSHException
+
+from microovn_rebuilder.remote.base import BaseConnector, ConnectorException
+from microovn_rebuilder.target import Target
+
+
+class SSHConnector(BaseConnector):
+    def __init__(self, remotes: List[str]) -> None:
+        super().__init__(remotes=remotes)
+
+        self.connections: Dict[str, SSHClient] = {}
+
+    def initialize(self) -> None:
+        for remote in self.remotes:
+            username, found, host = remote.partition("@")
+            try:
+                ssh = SSHClient()
+                ssh.load_system_host_keys()
+                if found:
+                    ssh.connect(hostname=host, username=username)
+                else:
+                    ssh.connect(hostname=remote)
+                self.connections[remote] = ssh
+            except SSHException as exc:
+                raise ConnectorException(
+                    f"Failed to connect to {remote}: {exc}"
+                ) from exc
+
+    def update(self, target: Target) -> None:
+        for remote, ssh in self.connections.items():
+            try:
+                with ssh.open_sftp() as sftp:
+                    local_stat = os.stat(str(target.local_path))
+                    print(
+                        f"{os.linesep}[{remote}] Removing remote file {target.remote_path}"
+                    )
+                    sftp.remove(str(target.remote_path))
+
+                    print(
+                        f"[{remote}] Uploading file {target.local_path} to {target.remote_path}"
+                    )
+                    sftp.put(target.local_path, str(target.remote_path))
+                    sftp.chmod(str(target.remote_path), local_stat.st_mode)
+                if target.service:
+                    print(f"[{remote}] Restarting {target.service}")
+                    self._run_command(ssh, remote, f"snap restart {target.service}")
+            except SSHException as exc:
+                raise ConnectorException(
+                    f"[{remote}] Failed to upload file: {exc}"
+                ) from exc
+
+    def check_remote(self, remote_dst: str) -> None:
+        for remote, ssh in self.connections.items():
+            self._run_command(ssh, remote, f"test -d {remote_dst}")
+
+    @staticmethod
+    def _run_command(ssh: SSHClient, remote: str, command: str) -> None:
+        try:
+            _, stdout, stderr = ssh.exec_command(command)
+            ret_code = stdout.channel.recv_exit_status()
+            if ret_code != 0:
+                error = stderr.read().decode("utf-8")
+                raise ConnectorException(
+                    f"[{remote}] Failed to execute command: {error}]"
+                )
+        except SSHException as exc:
+            raise ConnectorException(
+                f"[{remote}] Failed to execute command: {exc}"
+            ) from exc
+
+    def teardown(self) -> None:
+        for host, ssh in self.connections.items():
+            ssh.close()
+        self.connections.clear()