cloudvision/cvlib: Add utility method to get primary mgmt interface

Add getPrimaryManagementIntf utility method. This method is replicated
in four different studios today to support "Use OOB Mgmt Interface"
option. This provides us a single place to make changes to this
functionality. Also, added a check for preprovisioned devices to
return a default value.

Change-Id: I353661569bda755027d309969a1119783fb3c820

Author: shubhransh-crypto

cloudvision/cvlib/constants.py

@@ -16,3 +16,5 @@
 TIMEOUT_REQUEST = 60  # 1 min in seconds
 # General timeout for device command requests
 TIMEOUT_REQUEST_DI = 300  # 5 min in seconds
+
+SYSTYPE_TAG_LABEL = "systype"

cloudvision/cvlib/device.py

@@ -8,7 +8,20 @@
     TagMissingException,
     TagTooManyValuesException
 )
+from arista.tag.v2.services import (
+    TagAssignmentServiceStub,
+    TagAssignmentStreamRequest
+)
+from arista.tag.v2.tag_pb2 import (
+    TagAssignment,
+    ELEMENT_TYPE_DEVICE,
+    CREATOR_TYPE_SYSTEM
+)
 from .tags import Tag
+from .constants import (
+    MAINLINE_WS_ID,
+    SYSTYPE_TAG_LABEL
+)
 
 
 OLD_VEOS_REGEX = r'(v|c)EOS(-)*(Lab)*'
@@ -431,6 +444,54 @@ def getInterfacesByTag(self, ctx, tag: Tag, inTopology: bool = True):
                     interfaces.append(Interface(name=intfId, device=self))
         return interfaces
 
+    def getPrimaryManagementIntf(self, ctx):
+        '''
+        Returns the primary management interface of the device. This would be Management0 for
+        modular devices and Management1 for fixed systems. It also makes sure that the interface
+        Management1/1 exists on the device. If not, returns the first management interface in the
+        alphabetical sorted order.
+        '''
+        mgmtIntfs = []
+        for intf in self.getInterfaces():
+            if intf.name.startswith("Management"):
+                mgmtIntfs.append(intf.name)
+        if not mgmtIntfs:
+            # If the device mac is empty, it is an expected/pre-provisioned device. Should return a
+            # default value to prevent errors.
+            if not self.mac:
+                return "Management1"
+            return ""
+        mgmtIntfs.sort()
+        tagClient = ctx.getApiClient(TagAssignmentServiceStub)
+        tagRequest = TagAssignmentStreamRequest()
+        tagFilter = TagAssignment()
+        tagFilter.tag_creator_type = CREATOR_TYPE_SYSTEM
+        tagFilter.key.element_type = ELEMENT_TYPE_DEVICE
+        tagFilter.key.workspace_id.value = MAINLINE_WS_ID
+        tagFilter.key.label.value = SYSTYPE_TAG_LABEL
+        tagFilter.key.device_id.value = self.id
+        tagRequest.partial_eq_filter.append(tagFilter)
+        systemType = ""
+        primaryMgmtIntf = ""
+        for resp in tagClient.GetAll(tagRequest):
+            systemType = resp.value.key.value.value
+        if systemType.lower() == "fixed":
+            primaryMgmtIntf = "Management1"
+        elif systemType.lower() == "modular":
+            primaryMgmtIntf = "Management0"
+        elif systemType:
+            raise Exception("found unexpected systype tag for device")
+        else:
+            raise Exception("could not find systype tag for device")
+        # There are cases where Mgmt0 and Mgmt1 are not present and a different primary interface
+        # is needed. For example, devices with AWE sku have systype tag as fixed but don't have
+        # management1 on the device but Management1/1 interface instead.
+        # Checking this only for fixed systems as Management0 is not a physical interface
+        # and is not returned by device object.
+        if primaryMgmtIntf == "Management1" and primaryMgmtIntf not in mgmtIntfs:
+            primaryMgmtIntf = mgmtIntfs[0]
+        return primaryMgmtIntf
+
 
 # Interfaces and devices are defined together to avoid circular imports
 class Interface: