Boot cache dirctory

**Changes:**

* When program first executes, create the `~/.cvm/cache` directory if it does not already exist
* Check if a cached version of a tag name already exists yet or not

Author: morgan-wowk

src/app/bootstrap.py

@@ -1,4 +1,6 @@
 import argparse
+import logging
+import sys
 from typing import Optional
 
 from argparse_color_formatter import ColorRawTextHelpFormatter
@@ -9,6 +11,7 @@
 from src.app.commands.scan_command import ScanCommand
 from src.app.commands.use_command import UseCommand
 from src.app.helpers.helpers import colored_fore
+from src.app.services.cache_service import CacheService
 
 COMMAND_NAME = 'cvm'
 COMMAND_DESC = 'Composer Version Manager\n' + colored_fore(Fore.WHITE, 'Author: @game-of-morgan (Morgan Wowk)')
@@ -22,10 +25,16 @@
 
 
 def get_command_by_name(name: str) -> Optional[Command]:
-    return COMMANDS.get(name, None)()
+    command = COMMANDS.get(name, None)
+    if command is None:
+        logging.error("Command {} not found".format(name))
+        sys.exit(1)
+
+    return command()
 
 
 def run():
+    CacheService.boot_cache()
     parser = argparse.ArgumentParser(
         colored_fore(Fore.LIGHTGREEN_EX, COMMAND_NAME),
         formatter_class=ColorRawTextHelpFormatter,

src/app/commands/scan_command.py

@@ -5,7 +5,7 @@
 
 class ScanCommand(Command):
     NAME = 'scan'
-    DESCRIPTION = 'Use .cvm_config from the current directory if present.'
+    DESCRIPTION = 'If present use .cvm_config from the current or specified directory.'
 
     def exec(self, args: Namespace):
         print("Scan command executed.")

src/app/commands/use_command.py

@@ -7,8 +7,8 @@
 
 class UseCommand(Command):
     NAME = 'use'
-    DESCRIPTION = 'Use a specific version of Composer. Defaulting to the latest-\nstable version when there is a ' \
-                  'lack of specificity.\n\n '
+    DESCRIPTION = 'Use a specific version of Composer; Defaulting to the latest stable major version when there is a ' \
+                  'lack of specificity (ie. 2). '
 
     def exec(self, args: Namespace):
         desired_version = args.version[0]

src/app/services/cache_service.py

@@ -0,0 +1,19 @@
+import os
+import logging
+import sys
+from pathlib import Path
+
+
+class CacheService:
+    CACHE_DIR = os.path.expanduser('~') + '/.cvm/cache'
+
+    @staticmethod
+    def boot_cache():
+        home_directory = os.path.expanduser('~')
+
+        if not os.access(home_directory, os.W_OK) or not os.access(home_directory, os.X_OK):
+            logging.error('Permission to home directory is required.')
+            sys.exit(1)
+
+        if not os.path.exists(CacheService.CACHE_DIR):
+            Path(CacheService.CACHE_DIR).mkdir(parents=True, exist_ok=True)

src/app/services/composer_service.py

@@ -1,5 +1,7 @@
 import sys
+import os
 
+from src.app.services.cache_service import CacheService
 from src.app.services.github_service import GitHubService
 import logging
 
@@ -24,9 +26,10 @@ def tag_exists(self, desired_tag: str) -> bool:
 
         return False
 
-    def cache_exists(self, tag_name: str) -> bool:
+    @staticmethod
+    def cached_version_exists(tag_name: str) -> bool:
 
-        return True
+        return os.path.exists(CacheService.CACHE_DIR + "/{}".format(tag_name))
 
     def install_version(self, tag_name: str) -> bool:
         if not self.tag_exists(tag_name):
@@ -38,7 +41,7 @@ def install_version(self, tag_name: str) -> bool:
         return True
 
     def use_version(self, tag_name: str, check_exists: bool = True) -> bool:
-        if check_exists and not self.cache_exists(tag_name):
+        if check_exists and not ComposerService.cached_version_exists(tag_name):
             return False
 
         # TODO: Use cached version if exists