Adds argument to print vdb metadata (#180)

Signed-off-by: Prabhu Subramanian <prabhu@appthreat.com>

README.md

@@ -155,6 +155,7 @@ options:
   --download-image      Downloaded pre-created vdb image to platform specific user_data_dir. Application vulnerabilities only.
   --download-full-image
                         Downloaded pre-created vdb image to platform specific user_data_dir. All vulnerabilities including OS.
+  --print-vdb-metadata  Display metadata about the current vdb in user_data_dir.
 ```
 
 ### CLI search

vdb/cli.py

@@ -128,6 +128,13 @@ def build_args():
         dest="download_full_image",
         help="Downloaded pre-created vdb image to platform specific user_data_dir. All vulnerabilities including OS.",
     )
+    parser.add_argument(
+        "--print-vdb-metadata",
+        action="store_true",
+        default=False,
+        dest="print_vdb_metadata",
+        help="Display metadata about the current vdb in user_data_dir.",
+    )
     return parser.parse_args()
 
 
@@ -240,13 +247,28 @@ def create_db_file_metadata(sources, cve_data_count, cve_index_count):
     return metadata
 
 
+def print_db_file_metadata(metadata_file):
+    if not os.path.exists(metadata_file):
+        return
+    with open(metadata_file, encoding="utf-8") as fp:
+        db_meta = json.load(fp)
+        table = Table(title="VDB Summary", show_lines=True, caption=f"Metadata file: {metadata_file}")
+        table.add_column("Property")
+        table.add_column("Value")
+        for k, v in db_meta.items():
+            table.add_row(k, str(v))
+        console.print(table)
+
+
 def main():
     """Main function"""
     args = build_args()
     print(AT_LOGO)
     if args.clean:
         if os.path.exists(config.DATA_DIR):
             shutil.rmtree(config.DATA_DIR, ignore_errors=True)
+    if args.print_vdb_metadata:
+        print_db_file_metadata(config.VDB_METADATA_FILE)
     if args.download_image or args.download_full_image:
         db_url = config.VDB_DATABASE_URL if args.download_full_image else config.VDB_APP_ONLY_DATABASE_URL
         if ORAS_AVAILABLE:
@@ -256,6 +278,7 @@ def main():
                 config.DATA_DIR,
             )
             download_image(db_url, config.DATA_DIR)
+            print_db_file_metadata(config.VDB_METADATA_FILE)
         else:
             console.print(
                 "Oras library is not available. Install using 'pip install appthreat-vulnerability-db[oras]' and re-run this command.",