Azure: truncate long names better.

The resource group name limits to 80 (90 max) and vm name limits to
50 (64 max). the vm name will attach suffix, so it limits more.

The leading "lisa-" keeps in the name for two reasons.
1. It's needed to identify auto created envs, and delete by pipelines.
2. It avoids the random start chars like "-". It causes resource
    creation failure, because Azure accept name starts with chars only.

lisa/sut_orchestrator/azure/platform_.py

@@ -55,6 +55,7 @@
     get_public_key_data,
     plugin_manager,
     set_filtered_fields,
+    truncate_keep_prefix,
 )
 from lisa.util.logger import Logger
 from lisa.util.parallel import run_in_parallel
@@ -482,11 +483,11 @@ def _deploy_environment(self, environment: Environment, log: Logger) -> None:
             resource_group_name = self._azure_runbook.resource_group_name
         else:
             normalized_name = constants.NORMALIZE_PATTERN.sub("-", constants.RUN_NAME)
-            # Take last chars to make sure the length is to exceed max 64 chars
-            # allowed in vm names. The last chars include the datetime pattern,
-            # it's more unique than leading project/test pass names.
-            normalized_name = normalized_name[-40:]
-            resource_group_name = f"{normalized_name}-e{environment.id}"
+            # Take last chars to make sure the length is to exceed max 90 chars
+            # allowed in resource group name.
+            resource_group_name = truncate_keep_prefix(
+                f"{normalized_name}-e{environment.id}", 80
+            )
             environment_context.resource_group_is_created = True
 
         environment_context.resource_group_name = resource_group_name
@@ -1116,7 +1117,12 @@ def _create_node_runbook(
         )
 
         if not azure_node_runbook.name:
-            azure_node_runbook.name = f"{name_prefix}-n{index}"
+            # the max length of vm name is 64 chars. Below logic takes last 40
+            # chars in resource group name and keep the leading "lisa-". So it's
+            # easy to identify it's a lisa created node.
+            azure_node_runbook.name = truncate_keep_prefix(
+                f"{name_prefix}-n{index}", 50
+            )
         if not azure_node_runbook.vm_size:
             raise LisaException("vm_size is not detected before deploy")
         if not azure_node_runbook.location:

lisa/util/__init__.py

@@ -20,6 +20,7 @@
 )
 
 import pluggy
+from assertpy import assert_that
 from dataclasses_json import config
 from marshmallow import fields
 from semver import VersionInfo
@@ -492,3 +493,25 @@ def field_metadata(
 
 def is_unittest() -> bool:
     return "unittest" in sys.argv[0]
+
+
+def truncate_keep_prefix(content: str, kept_len: int, prefix: str = "lisa-") -> str:
+    """
+    This method is used to truncate names, when some resource has length
+    limitation. It keeps meaningful part and the defined prefix.
+
+    The last chars include the datetime pattern, it's more unique than leading
+    project/test pass names. The name is used to identify lisa deployed
+    environment too, so it needs to keep the leading "lisa-" after truncated.
+
+    This makes the name from lisa-long-name... to lisa-name...
+    """
+    if not content.startswith(prefix):
+        assert_that(content).described_as(
+            "truncate_keep_prefix should be start with prefix"
+        ).starts_with(prefix)
+    if kept_len < len(prefix):
+        assert_that(len(prefix)).described_as(
+            f"kept length must be greater than prefix '{prefix}'"
+        ).is_less_than_or_equal_to(kept_len)
+    return f"{prefix}{content[len(prefix) : ][-kept_len+len(prefix):]}"