feat: print identity and provider during signing (#52)

* print identity and providr during signing

Signed-off-by: laurentsimon <laurentsimon@google.com>

* update

Signed-off-by: laurentsimon <laurentsimon@google.com>

* fix linter

Signed-off-by: laurentsimon <laurentsimon@google.com>

---------

Signed-off-by: laurentsimon <laurentsimon@google.com>

model_signing/model.py

@@ -17,6 +17,7 @@
 )
 from sigstore._internal.oidc import (
     DEFAULT_AUDIENCE,
+    Identity
 )
 from sigstore.oidc import (
     Issuer,
@@ -37,6 +38,7 @@
 from typing import Optional
 from serialize import Serializer
 import psutil
+import sys
 
 
 def chunk_size() -> int:
@@ -103,6 +105,12 @@ def sign(self, inputfn: Path, signaturefn: Path,
             if not token:
                 raise ValueError("No identity token supplied or detected!")
 
+            # Print identity used to sign the model.
+            oidc_identity = Identity(token)
+            print(f"identity-provider: {oidc_identity.issuer}",
+                  file=sys. stderr)
+            print(f"identity: {oidc_identity.proof}", file=sys. stderr)
+
             contentio = io.BytesIO(Serializer.serialize_v1(
                 inputfn, chunk_size(), signaturefn, ignorepaths))
             result = self.signer.sign(input_=contentio, identity_token=token)