don't require every plugin recorded in bundle (azavea#1916)

The model bundles record every rastervision plugin that was installed when they were created and it was required to have all those plugins installed when using those bundles even if not actually needed. This change removes that requirement.

Co-authored-by: Adeel Hassan <ahassan@element84.com>

rastervision_pipeline/rastervision/pipeline/config.py

@@ -1,5 +1,6 @@
 from typing import List, Type, Union, Optional, Callable, Dict, TYPE_CHECKING
 import inspect
+import logging
 
 from pydantic import (  # noqa
     BaseModel, create_model, Field, root_validator, validate_model,
@@ -14,6 +15,8 @@
 if TYPE_CHECKING:
     from rastervision.pipeline.pipeline_config import PipelineConfig
 
+log = logging.getLogger(__name__)
+
 
 class ConfigError(ValueError):
     """Exception raised for invalid configuration."""
@@ -212,14 +215,16 @@ def upgrade_plugin_versions(plugin_versions: Dict[str, int]) -> Dict[str, int]:
 
     """
     new_plugin_versions = {}
+    missing_plugins = []
     for alias, version in plugin_versions.items():
         plugin = registry.get_plugin_from_alias(alias)
         if plugin:
             new_plugin_versions[plugin] = version
         else:
-            raise ConfigError(
-                'The plugin_versions field contains an unrecognized '
-                f'plugin name: {alias}.')
+            missing_plugins.append(alias)
+    if len(missing_plugins) > 0:
+        log.warning('There are plugins listed in the pipeline config that are '
+                    f'not currently installed: {missing_plugins}')
     return new_plugin_versions