add NWCS datasource (#1793)

I am writing a cloud platform (nwcs) and need to add support
to cloud-init.

1 files changed, 168 insertions, 0 deletions

diff --git a/cloudinit/sources/DataSourceNWCS.py b/cloudinit/sources/DataSourceNWCS.py
new file mode 100644
index 00000000..e21383d2
--- /dev/null
+++ b/cloudinit/sources/DataSourceNWCS.py
@@ -0,0 +1,168 @@
+# This file is part of cloud-init. See LICENSE file for license information.
+
+from requests import exceptions
+
+from cloudinit import dmi
+from cloudinit import log as logging
+from cloudinit import net, sources, subp, url_helper, util
+from cloudinit.net.dhcp import NoDHCPLeaseError
+from cloudinit.net.ephemeral import EphemeralDHCPv4
+
+LOG = logging.getLogger(__name__)
+
+BASE_URL_V1 = "http://169.254.169.254/api/v1"
+
+BUILTIN_DS_CONFIG = {
+    "metadata_url": BASE_URL_V1 + "/metadata",
+}
+
+MD_RETRIES = 30
+MD_TIMEOUT = 5
+MD_WAIT_RETRY = 5
+
+
+class DataSourceNWCS(sources.DataSource):
+
+    dsname = "NWCS"
+
+    def __init__(self, sys_cfg, distro, paths):
+        sources.DataSource.__init__(self, sys_cfg, distro, paths)
+        self.distro = distro
+        self.metadata = dict()
+        self.ds_cfg = util.mergemanydict(
+            [
+                util.get_cfg_by_path(sys_cfg, ["datasource", "NWCS"], {}),
+                BUILTIN_DS_CONFIG,
+            ]
+        )
+        self.metadata_address = self.ds_cfg["metadata_url"]
+        self.retries = self.ds_cfg.get("retries", MD_RETRIES)
+        self.timeout = self.ds_cfg.get("timeout", MD_TIMEOUT)
+        self.wait_retry = self.ds_cfg.get("wait_retry", MD_WAIT_RETRY)
+        self._network_config = sources.UNSET
+        self.dsmode = sources.DSMODE_NETWORK
+
+    def _get_data(self):
+        LOG.info("Detecting if machine is a NWCS instance")
+        on_nwcs = get_nwcs_data()
+
+        if not on_nwcs:
+            LOG.info("Machine is not a NWCS instance")
+            return False
+
+        LOG.info("Machine is a NWCS instance")
+
+        md = self.get_metadata()
+
+        if md is None:
+            raise Exception("failed to get metadata")
+
+        self.metadata_full = md
+
+        self.metadata["instance-id"] = md["instance-id"]
+        self.metadata["public-keys"] = md["public-keys"]
+        self.metadata["network"] = md["network"]
+        self.metadata["local-hostname"] = md["hostname"]
+
+        self.userdata_raw = md.get("userdata", None)
+
+        self.vendordata_raw = md.get("vendordata", None)
+
+        return True
+
+    def get_metadata(self):
+        try:
+            LOG.info("Attempting to get metadata via DHCP")
+
+            with EphemeralDHCPv4(
+                iface=net.find_fallback_nic(),
+                connectivity_url_data={
+                    "url": BASE_URL_V1 + "/metadata/instance-id",
+                },
+            ):
+                return read_metadata(
+                    self.metadata_address,
+                    timeout=self.timeout,
+                    sec_between=self.wait_retry,
+                    retries=self.retries,
+                )
+
+        except (
+            NoDHCPLeaseError,
+            subp.ProcessExecutionError,
+            RuntimeError,
+            exceptions.RequestException,
+        ) as e:
+            LOG.error("DHCP failure: %s", e)
+            raise
+
+    @property
+    def network_config(self):
+        LOG.debug("Attempting network configuration")
+
+        if self._network_config is None:
+            LOG.warning(
+                "Found None as cached _network_config, resetting to %s",
+                sources.UNSET,
+            )
+            self._network_config = sources.UNSET
+
+        if self._network_config != sources.UNSET:
+            return self._network_config
+
+        if not self.metadata["network"]["config"]:
+            raise Exception("Unable to get metadata from server")
+
+        # metadata sends interface names, but we dont want to use them
+        for i in self.metadata["network"]["config"]:
+            iface_name = get_interface_name(i["mac_address"])
+
+            if iface_name:
+                LOG.info("Overriding %s with %s", i["name"], iface_name)
+                i["name"] = iface_name
+
+        self._network_config = self.metadata["network"]
+
+        return self._network_config
+
+
+def get_nwcs_data():
+    vendor_name = dmi.read_dmi_data("system-manufacturer")
+
+    if vendor_name != "NWCS":
+        return False
+
+    return True
+
+
+def get_interface_name(mac):
+    macs_to_nic = net.get_interfaces_by_mac()
+
+    if mac not in macs_to_nic:
+        return None
+
+    return macs_to_nic.get(mac)
+
+
+# Return a list of data sources that match this set of dependencies
+def get_datasource_list(depends):
+    return sources.list_from_depends(depends, datasources)
+
+
+def read_metadata(url, timeout=2, sec_between=2, retries=30):
+    response = url_helper.readurl(
+        url, timeout=timeout, sec_between=sec_between, retries=retries
+    )
+
+    if not response.ok():
+        raise RuntimeError("unable to read metadata at %s" % url)
+
+    return util.load_json(response.contents.decode())
+
+
+# Used to match classes to dependencies
+datasources = [
+    (DataSourceNWCS, (sources.DEP_FILESYSTEM,)),
+]
+
+# vi: ts=4 expandtab