From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Gibson <david@gibson.dropbear.id.au>
To: passt-dev@passt.top
Subject: Re: [PATCH 17/18] tests: Correct determination of host interface name
 in tests
Date: Tue, 19 Jul 2022 16:20:45 +1000
Message-ID: <YtZNPZcskrY+P+Cv@yekko>
In-Reply-To: <20220715052141.890703-18-david@gibson.dropbear.id.au>
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="===============0242579824663688058=="

--===============0242579824663688058==
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: quoted-printable

On Fri, Jul 15, 2022 at 03:21:40PM +1000, David Gibson wrote:
> By default, passt itself attaches to the first host interface with a
> default route.  However, when determining the host interface name the tests
> implicitly select the *last* host interface: they use a jq expression which
> will list all interfaces with default routes, but the way output detection
> works in the scripts, it will only pick up the last line.
>=20
> If there are multiple interfaces with default routes on the host, and they
> each have a different address, this can cause spurious test
> failures.

It seems this change is not enough to always fix the tests when there
are multiple default routes.  I'm still sometimes getting failures,
now because passt itself doesn't seem to be picking the interface
with the first default route.

I'm wondering if this is because ip(8) is sorting the output, not just
presenting it in the same order that the underlying netlink interface
does.

> Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
> ---
>  test/dhcp/passt       | 2 +-
>  test/two_guests/basic | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>=20
> diff --git a/test/dhcp/passt b/test/dhcp/passt
> index 3d2e939..f45227a 100644
> --- a/test/dhcp/passt
> +++ b/test/dhcp/passt
> @@ -16,7 +16,7 @@ htools	ip jq sed tr head
> =20
>  test	Interface name
>  gout	IFNAME ip -j link show | jq -rM '.[] | select(.link_type =3D=3D "ethe=
r").ifname'
> -hout	HOST_IFNAME ip -j -4 route show|jq -rM '.[] | select(.dst =3D=3D "def=
ault").dev'
> +hout	HOST_IFNAME ip -j -4 route show|jq -rM '[.[] | select(.dst =3D=3D "de=
fault").dev] | .[0]'
>  check	[ -n "__IFNAME__" ]
> =20
>  test	DHCP: address
> diff --git a/test/two_guests/basic b/test/two_guests/basic
> index cf0b975..f7c016d 100644
> --- a/test/two_guests/basic
> +++ b/test/two_guests/basic
> @@ -18,7 +18,7 @@ htools	ip jq md5sum cut
>  test	Interface names
>  g1out	IFNAME1 ip -j link show | jq -rM '.[] | select(.link_type =3D=3D "et=
her").ifname'
>  g2out	IFNAME2 ip -j link show | jq -rM '.[] | select(.link_type =3D=3D "et=
her").ifname'
> -hout	HOST_IFNAME ip -j -4 route show|jq -rM '.[] | select(.dst =3D=3D "def=
ault").dev'
> +hout	HOST_IFNAME ip -j -4 route show|jq -rM '[.[] | select(.dst =3D=3D "de=
fault").dev] | .[0]'
>  check	[ -n "__IFNAME1__" ]
>  check	[ -n "__IFNAME2__" ]
> =20

--=20
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

--===============0242579824663688058==
Content-Type: application/pgp-signature
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="signature.asc"
MIME-Version: 1.0
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--===============0242579824663688058==--