Nice way to handle env variable?

[Prizrako]

Some methods to set environment varialbes for single command, instead of this:

os.Setenv("XB_AUTHOR_DATE", dateStr)
os.Setenv("XB_COMMITTER_DATE", dateStr)

Maybe in old shell way:

XB_AUTHOR_DATE="2021-04-05" XB_COMMITTER_DATE="2021-04-05" xb_push xxxx

[No-one-important]

would
script.Env("variable", "value").Exec("command")
be a suitable solution

[bitfield]

I'm not seeing where this adds much value over, for example:

script.Exec("sh -c 'export MSG=hello; echo $MSG'").Stdout()

[No-one-important]

on windows that syntax is not possible

[bitfield]

That's a fair point, but what about os.Setenv, for example?

[No-one-important]

It works but I think it would cleaner to have it inline and builtin to the module.

[bitfield]

Useful abstractions, as John Ousterhout says, should be deep: they should conceal lots of functionality behind a simple API. Is there any way we could do more than simply call os.Setenv? Some example programs that need to set their environment would be useful. What about reading an envfile, for example?

[josegonzalez]

I think it might be nice to not use os.Setenv() and instead only set them for a Pipeline - maybe something like a wrapper around script.Exec("sh -c 'export KEY=value; true'"), but for potentially multiple key/value pairs? In this way, we scope environment variables to just the pipeline rather than the entire golang process that is invoking/utilizing the pipeline.

Note that the wrapper would probably need to properly escape the environment variables, so it wouldn't be as simple as a fmt.Sprintf() call. Maybe thats enough deepness for it to be implemented?

[bitfield]

That sounds good, @josegonzalez—can you write a short piece of example code to show what you mean?

[josegonzalez]

Maybe something like the following:

environ := map[string]string{
  "HASURA_GRAPHQL_JWT_SECRET": "{\"type\": \"HS256\", \"key\": \"256BITKEYHERE$\"}"
}
contents, err := script.Env(env).Exec("env")

[bitfield]

Okay, but this looks pretty similar to:

os.Setenv("HASURA_GRAPHQL_JWT_SECRET", `{"type": "HS256", "key": "256BITKEYHERE$"}`)
contents, err := script.Exec("env")

Can you describe what problem you think an Env method on the pipe would be solving here?

[No-one-important]

os.Setenv would be global to the entire script this would allow it be local to the pipe

[bitfield]

Okay, but why is that important? Can you think of a situation where you'd want to set some environment variable for a command run by a pipe, but not for the program as a whole?

[No-one-important]

I'm not sure of the usecases but it just allows the same flexibility that the bash syntax allows but for all OSs

[bitfield]

Well, if there are no use cases for something, that's just another way of saying we don't need it, isn't it? There are lots of feature ideas that aren't bad in themselves—they're great features! It's just that we don't need them, so we don't add them.

[bitfield]

Closing pending real use cases.