allow override chroot with New()

[jaypipes]

Adds the ability to override the CHROOT and whether to only use the cached pciids file using options passed to the pcidb.New() function. The chroot still defaults to the PCIDB_CHROOT environs variable value, if set, but now it's possible to set this configuration value like so:

pci := pcidb.New(pcidb.WithChroot("/override"))

Issue #12

[jaypipes]

@chiptus @deviantony mind taking a look at this PR?

[chiptus]

LGTM The implementation of the mergeOptions seems huge and prone to errors, but since there's a test for this I think it's ok. Would be nice to have some generic implementation you can use for ghw too. Good work, thank you for your time

On Tue, Nov 13, 2018 at 5:05 PM Jay Pipes notifications@github.com wrote:

@chiptus https://github.com/chiptus @deviantony https://github.com/deviantony mind taking a look at this PR?

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[jaypipes]

@chiptus most of the new code is actually just moved from the discover.go module (where it was hard-coding the lookup of environ vars) to the main.go module, so not a whole lot of new code. I needed to use the pointer-to-string and pointer-to-bool stuff in order to check for the absence of values.

I was modeling the WithChroot(), WithCacheOnly() modifier functions after the way that etcd's clientv3.KVS class works, where you can pass zero or more WithSort() or WithPrefix() modifiers to methods like Op.Put(). I found it a nice and consistent user experience that allows using the same function/method without any modifiers and still get a coherent interface.

Anyway, thanks for taking a look! :)

-jay

[deviantony]

Ah it's merged already, sorry, TZ issue I guess :-)

Thanks @jaypipes