[python] Print nicer errors in gramine-manifest

Signed-off-by: Michał Kowalczyk <[email protected]>

python/gramine-manifest

@@ -6,6 +6,11 @@
 import click
 import voluptuous
 
+try:
+    from tomllib import TOMLDecodeError
+except ImportError:
+    from tomli import TOMLDecodeError
+
 from graminelibos import Manifest
 
 def validate_define(_ctx, _param, values):
@@ -28,9 +33,13 @@ def validate_define(_ctx, _param, values):
 @click.pass_context
 def main(ctx, string, define, infile, outfile, check):
     if not bool(string) ^ bool(infile):
-        click.get_current_context().fail('specify exactly one of (infile, -c)')
+        ctx.fail('specify exactly one of (infile, -c)')
     template = infile.read() if infile else string
-    manifest = Manifest.from_template(template, define)
+    try:
+        manifest = Manifest.from_template(template, define)
+    except TOMLDecodeError as err:
+        click.echo(f'ERROR: failed to parse manifest template: {err!s}', err=True)
+        ctx.exit(1)
 
     if check:
         try: