Reduce number of created temporary files

slapos/libnetworkcache.py

@@ -343,79 +343,46 @@ class NetworkcacheClient(object):
           filtered_data_list.append(data)
     return filtered_data_list
 
+  def _openssl(self, input, *args):
+    p = subprocess.Popen((self.openssl,) + args,
+                         stdin=subprocess.PIPE, stdout=subprocess.PIPE)
+    output = p.communicate(input)[0]
+    if p.returncode:
+      raise subprocess.CalledProcessError(p.returncode, self.openssl, output)
+    return output
+
   def _getSignatureString(self, content):
     """
       Return the signature based on certification file.
     """
     if self.signature_private_key_file is None:
       return ''
-
-    content_file = tempfile.NamedTemporaryFile()
-    content_file.write(content)
-    content_file.flush()
-    content_file.seek(0)
-    try:
-      signature = subprocess.check_output([self.openssl, "dgst", "-sha1",
-            "-sign", self.signature_private_key_file, content_file.name])
-      return signature.encode('base64')
-    finally:
-      content_file.close()
+    return self._openssl(content, "dgst", "-sha1", "-sign",
+      self.signature_private_key_file).encode('base64')
 
   def _verifySignatureInCertificateList(self, content, signature_string):
     """
       Returns true if it can find any valid certificate or false if it does not
       find any.
     """
-    if self.signature_certificate_list is not None:
-      for certificate in self.signature_certificate_list:
-        if self._verifySignatureCertificate(content, signature_string,
-            certificate):
-          return True
-    return False
-
-  def _verifySignatureCertificate(self, content, signature_string,
-      certificate):
-    """ verify if the signature is valid for a given certificate. """
-    certificate_file = tempfile.NamedTemporaryFile()
-    certificate_file.write(certificate)
-    certificate_file.flush()
-    certificate_file.seek(0)
-    signature_file = tempfile.NamedTemporaryFile()
+    if self.signature_certificate_list:
+      with tempfile.NamedTemporaryFile() as signature_file:
         signature_file.write(signature_string.decode('base64'))
         signature_file.flush()
-    signature_file.seek(0)
-    content_file = tempfile.NamedTemporaryFile()
-    content_file.write(content)
-    content_file.flush()
-    content_file.seek(0)
-    pubkey_file = tempfile.NamedTemporaryFile()
-    try:
-      last_output = ''
+        for certificate in self.signature_certificate_list:
           try:
-        last_output = subprocess.check_output([self.openssl, "x509", "-pubkey",
-            "-noout", "-in", certificate_file.name])
-        pubkey_file.write(last_output)
+            pubkey = self._openssl(certificate, "x509", "-pubkey", "-noout")
+            with tempfile.NamedTemporaryFile() as pubkey_file:
+              pubkey_file.write(pubkey)
               pubkey_file.flush()
-        pubkey_file.seek(0)
-        try:
-          last_output = subprocess.check_output([self.openssl, "dgst", "-sha1",
-              "-verify", pubkey_file.name, "-signature", signature_file.name,
-              content_file.name])
-        except subprocess.CalledProcessError, e:
-          # in case if verification failed
-          last_output = e.output
-        if last_output.startswith('Verified OK'):
+              if self._openssl(content, "dgst", "-sha1", "-verify",
+                  pubkey_file.name, "-signature", signature_file.name
+                  ).startswith('Verified OK'):
                 return True
           except Exception:
             # in case of failure, emit *anything*, but swallow all what possible
-        print last_output
-        print traceback.format_exc()
+            traceback.print_exc()
     return False
-    finally:
-      certificate_file.close()
-      signature_file.close()
-      content_file.close()
-      pubkey_file.close()
 
 
 class DirectoryNotFound(Exception):