32 lines
896 B
Go
32 lines
896 B
Go
package opts
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import (
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"errors"
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"os"
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"strings"
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)
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// ValidateEnv validates an environment variable and returns it.
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// If no value is specified, it obtains its value from the current environment.
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//
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// Environment variable names are not validated, and it's up to the application
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// inside the container to validate them (see [moby-16585]). The only validation
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// here is to check if name is empty, per [moby-25099].
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//
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// [moby-16585]: https://github.com/moby/moby/issues/16585
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// [moby-25099]: https://github.com/moby/moby/issues/25099
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func ValidateEnv(val string) (string, error) {
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k, _, hasValue := strings.Cut(val, "=")
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if k == "" {
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return "", errors.New("invalid environment variable: " + val)
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}
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if hasValue {
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// val contains a "=" (but value may be an empty string)
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return val, nil
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}
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if envVal, ok := os.LookupEnv(k); ok {
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return k + "=" + envVal, nil
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}
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return val, nil
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}
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