snap: support "command: foo $ENV_STRING" #3995
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mvo5
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cmd/snap-exec/main.go
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| tmpCmdArgv := strings.Split(cmdAndArgs, " ") | ||
| cmd := tmpCmdArgv[0] | ||
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| cmdArgs := make([]string, 0, len(tmpCmdArgv[1:])) |
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I'd feel better if this was a separate function that can be tested in isolation.
tests/lib/snaps/basic-run/bin/echo
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| @@ -0,0 +1,3 @@ | |||
| #!/bin/sh | |||
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| echo $1 | |||
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Nitpick, use "$@" instead of $1 as that has special expansion rules and lets us use multiple arguments.
| @@ -0,0 +1,6 @@ | |||
| name: basic-run | |||
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There is a snap called test-snapd-sh that lets you run sh directly without any fuss. Would it suffice?
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Not sure, what I need is a env variable inside the command: part of the app. I could add that to another test snap of course if you think this is overkill.
| @@ -15,9 +15,6 @@ prepare: | | |||
| restore: | | |||
| rm basic-hooks_1.0_all.snap | |||
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| restore: | | |||
tests/main/snap-run/task.yaml
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| . $TESTSLIB/snaps.sh | ||
| install_local basic-run | ||
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| restore: | |
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I believe that we don't need to remove those snaps as install_local handles that now.
| @@ -15,9 +15,6 @@ prepare: | | |||
| restore: | | |||
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I believe we don't need to remove those manually as install_local handles that now.
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Maybe I'm missing something, but I don't see any cleanup code in install_local() in snaps.sh. It would be very desirable though.
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Right, sorry. What I meant was that install_local caches the built snap at a separate location and that we don't have to remove the built snap explicitly.
cmd/snap-exec/main.go
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| // strings.Split() is ok here because we validate all app fields | ||
| // and the whitelist is pretty strict (see | ||
| // snap/validate.go:appContentWhitelist) | ||
| tmpCmdArgv := strings.Split(cmdAndArgs, " ") |
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Can you please add a comment to https://github.com/snapcore/snapd/blob/master/snap/validate.go#L168 so that if the regexp there ever contains ", ' or ` then we need to adjust shell argument parser used here.
cmd/snap-exec/main.go
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| for _, kv := range env { | ||
| l := strings.SplitN(kv, "=", 2) | ||
| if len(l) == 2 { | ||
| if k == l[0] { |
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You could use a map to get rid of the quadratic complexity here.
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@mvo5 the tests fail on |
osutil/env.go
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| // EnvMap takes a list of "key=value" strings and transforms them into | ||
| // a map. | ||
| func EnvMap(env []string) map[string]string { | ||
| out := make(map[string]string) |
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you might as well make it of size len(env)
| func expandEnvCmdArgs(args []string, env map[string]string) []string { | ||
| cmdArgs := make([]string, 0, len(args)) | ||
| for _, arg := range args { | ||
| maybeExpanded := os.Expand(arg, func(k string) string { |
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I need to look into what defining the function inside the for looks like, compared to defining it outside; a priori it makes me nervous :-)
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... benchmarking says they're indistinguishable. Fair 'nuf.
Tiny branch that will allow to use environment strings in the "command:" part of meta/snap.yaml. Needs some more tests but pushing now to get the benefit of spread tests (here at the airport that is a bit tricky to run locally with the given network).