Add resource based validation

tricot/__init__.py

@@ -8,5 +8,6 @@
 from .tricot import *
 from .validation import *
 from .extractor import *
+from .resource import *
 
 name = 'tricot'

tricot/main.py

@@ -330,8 +330,8 @@ def main():
                     tricot.Logger.print_with_indent_blue(str(e), e=True)
                     sys.exit(tricot.constants.PARSER_ERROR)
 
-                except tricot.TricotRequiredFile as e:
-                    tricot.Logger.print_mixed_yellow('Error: Test configuration requires missing file:', str(e), e=True)
+                except tricot.ResourceValidationException as e:
+                    tricot.Logger.print_mixed_yellow('Error: a resource validation has failed:', str(e), e=True)
                     tricot.Logger.print_mixed_blue('Affected configuration:', wrapper.path, e=True)
                     sys.exit(tricot.constants.MISSING_RESOURCE)
 

tricot/resource.py

@@ -0,0 +1,112 @@
+#!/usr/bin/env python3
+
+from __future__ import annotations
+
+import os
+import pathlib
+import hashlib
+import requests
+
+from tricot.logging import Logger
+
+
+class ResourceValidationException(Exception):
+    '''
+    '''
+
+
+class Resource:
+    '''
+    The resource class represents an additional resource that
+    is required for tricot to run. These can be specified within
+    tricot configuration files.
+    '''
+
+    def __init__(self, attrs: dict) -> None:
+        '''
+        Initialize the resource with attributes taken from the
+        yaml file.
+        
+        Parameters:
+            attrs           attributes to initialize the resource with
+
+        Returns:
+            None
+        '''
+        self.url = None
+        self.path = None
+        self.hash = None
+        self.mode = None
+
+        for key, value in attrs.items():
+
+            if key == 'path':
+                self.path = value
+
+            elif key == 'url':
+                self.url = value
+
+            elif key == 'hash':
+                self.hash = value
+
+            elif key == 'mode':
+                self.mode = value
+
+            else:
+                raise ResourceValidationException('Unknown resource attribute:' + key)
+
+        if self.path is None:
+            raise ResourceValidationException('Required "path" attribute is missing.')
+
+
+    def validate(self) -> None:
+        '''
+        Validates whether the resource has the correct state.
+        Missing files are downloaded if url attribute was specified.
+        Files with incorrect permissions are adjusted.
+
+        Parameters:
+            None
+
+        Returns:
+            None
+        '''
+        path = pathlib.Path(self.path).expanduser()
+
+        if not path.is_file():
+
+            if not self.url:
+                raise ResourceValidationException(f'{path}: does not exist.')
+
+            Logger.print_mixed_yellow('Downloading missing resource from:', self.url)
+            r = requests.get(self.url)
+
+            if r.status_code != 200:
+                raise ResourceValidationException(f'{self.url}: did not return 200.')
+
+            Logger.print_mixed_blue('Writing resource data to:', str(path))
+            path.write_bytes(r.content)
+
+        if self.mode:
+            Logger.print_mixed_blue('Adjusting permissions of resource to:', self.mode)
+            os.chmod(path, int(self.mode, 8))
+
+        if self.hash:
+
+            triggered = False
+            content = path.read_bytes()
+
+            for hash_type in ['md5', 'sha1', 'sha256', 'sha512']:
+
+                hash_value = self.hash.get(hash_type)
+
+                if hash_value is not None:
+
+                    triggered = True
+                    computed = hashlib.new(hash_type, content).hexdigest()
+
+                    if computed != hash_value:
+                        raise ResourceValidationException(f'{path}: {computed} != {hash_value}')
+
+            if not triggered:
+                raise ResourceValidationException('hash attribute contains no valid hash types.')

tricot/tricot.py

@@ -15,6 +15,7 @@
 from tricot.plugin import Plugin
 from tricot.command import Command
 from tricot.condition import Condition
+from tricot.resource import Resource
 
 
 skip_until = None
@@ -40,12 +41,6 @@ def __init__(self, message: str, path: Path = None) -> None:
         super().__init__(message)
 
 
-class TricotRequiredFile(Exception):
-    '''
-    Custom exception class for a missing required file.
-    '''
-
-
 class TricotRequiredCommand(Exception):
     '''
     Custom exception class for a missing required command.
@@ -864,13 +859,15 @@ def check_requirements(self):
 
         for file in requires.get('files', []):
 
-            if type(file) is str and not Path(file).exists():
-                raise ExceptionWrapper(TricotRequiredFile(file), self.path)
+            try:
+                if type(file) is str:
+                    Resource({'path': file}).validate()
 
-            elif type(file) is dict:
+                elif type(file) is dict:
+                    Resource(file).validate()
 
-                if not tricot.utils.file_integrity(file):
-                    raise ExceptionWrapper(TricotRequiredFile(file.get('filename') + " (wrong hash value)"), self.path)
+            except Exception as e:
+                raise ExceptionWrapper(e, self.path)
 
         for command in requires.get('commands', []):