+
+def ca_certs_path(fallback=httplib2.CA_CERTS):
+ """Return the path of the best available CA certs source.
+
+ This function searches for various distribution sources of CA
+ certificates, and returns the first it finds. If it doesn't find any,
+ it returns the value of `fallback` (httplib2's CA certs by default).
+ """
+ for ca_certs_path in [
+ # Arvados specific:
+ '/etc/arvados/ca-certificates.crt',
+ # Debian:
+ '/etc/ssl/certs/ca-certificates.crt',
+ # Red Hat:
+ '/etc/pki/tls/certs/ca-bundle.crt',
+ ]:
+ if os.path.exists(ca_certs_path):
+ return ca_certs_path
+ return fallback