On Tue, 26 Mar 2024 11:31:31 +0100 Petr Machata wrote:
Jakub Kicinski kuba@kernel.org writes:
On Mon, 25 Mar 2024 18:29:10 +0100 Petr Machata wrote:
+The forwarding selftests framework uses a number of variables that +influence its behavior and tools it invokes, and how it invokes them, in +various ways. A number of these variables can be overridden. The way these +overridable variables are specified is typically one of the following two +syntaxes:
- : "${VARIABLE:=default_value}"
- VARIABLE=${VARIABLE:=default_value}
+Any of these variables can be overridden. Notably net/forwarding/lib.sh and +net/lib.sh contain a number of overridable variables.
+One way of overriding these variables is through the environment:
- PAUSE_ON_FAIL=yes ./some_test.sh
I like this conversion a lot. Makes me want to propose that we make this
Convention you mean?
Yes, sorry
Nothing was converted, this has always worked.
Right, for forwarding and perhaps net.
a standard feature of kselftest. If "env" file exists in the test directory kselftest would load its contents before running every test.
That's more of a broader question to anyone reading on linux-kselftest@ if there's no interest more than happy to merge as is :)
+The variable NETIFS is special. Since it is an array variable, there is no +way to pass it through the environment. Its value can instead be given as +consecutive arguments to the selftest:
- ./some_test.sh swp{1..8}
Did you consider allowing them to be defined as NETIF_0, NETIF_1 etc.? We can have lib.sh convert that into an array with a ugly-but-short loop, it's a bit tempting to get rid of the exception.
The exception is a bit annoying, yeah. But it works today, should stay, and therefore should be documented, so the paragraph won't go away. I use it all the time, too. I basically don't use the config file, I just use the env overrides and the argv interface names. It's very handy.
The alternative is also very verbose:
NETIF_1=swp1 NETIF_2=swp2 NETIF_3=swp3 [...] ./some_test.sh.
Maybe we could do this though?
NETIFS="swp1 swp2 swp3 swp4 swp5 swp6 swp7 swp8" ./some_test.sh
And like this it won't make you want to pull your hair from all the repetition:
NETIFS=$(echo swp{1..8}) ./some_test.sh
But NETIFS is going to be a special case one way or another. That you need to specify it through several variables, or a variable with a special value, means you need to explain it as a special case in the documentation. At which point you have two exceptions, and an interaction between them, to describe.
I think there's some value in passing all inputs in the same way (thru env rather than argv). I guess it's subjective, you're coding it up, so you can pick.