`os.networkInterfaces` does not list all interfaces.

[zenoamaro]

Adoption of nodejs/node-v0.x-archive#9029.

os.networkInterfaces() does not list all interfaces, but only those that have addresses, excluding for example an unplugged eth0, which can be surprising.

This happens because os.networkInterfaces is actually implemented in terms of GetInterfaceAddresses which calls into uv_interface_addresses (which among other things filters out everything except AF_INET*) making networkInterfaces a bit of a misnomer for what is basically networkInterfaceAddresses.

Though os is at stability 4 already, this behavior can be a bit unexpected. Perhaps we could correct it somewhat without breaking the API, or at least document it. I can think of a few ways to work this out:

• Leave the method as it is, but document the exceptional behavior in the docs, and leave it to a community module to solve this correctly; or
• Alias it to os.networkInterfaceAddresses, thus reflecting GetInterfaceAddresses and uv_interface_addresses; or
• Implement uv_interfaces and rebase os.networkInterfaces() on that and uv_interface_addresses, preserving the current behavior, but listing all interfaces when given a flag.

1. yes
2. os
3. v0.10, v0.12, v1.0.0

[rvagg]

os.networkInterfaces({ all: true }) wouldn't be a breaking change, I'm +1 for that; not having the ability to list all interfaces is a bit of a handicap for the platform

[bnoordhuis]

It would require a (tedious) update to libuv, however. Tedious because it needs to be applied to all platforms and because it's an API change. Whoever wants to pursue that, please file a libuv issue first so we can hash out the details.

[zenoamaro]

+1 for { all: true } and similar approaches. It's unlikely for networkInterfaces to receive an object with this shape by accident. Conversely, trying to invoke the new behavior on node.js will still return a valid list of interfaces (with down interfaces missing as usual).

I believe libuv would only need a single addition (uv_interfaces and possibly uv_free_interfaces) without changes in existing code. The remaining job of meshing uv_interfaces and uv_interface_addresses together would be entirely done on the io.js bindings. I'll open an issue there and try a POC.

[piranna]

+1 for { all: true }. Until that, what workarounds could be used?

[brendanashworth]

@piranna I don't believe there is a core workaround right now, unless there is an npm module somewhere.

[piranna]

I don't know of any npm module about this... :-(

[Trott]

This issue appears to be dormant and doesn't seem likely to get any traction any time soon because it depends on a significant feature appearing in libuv first. Would it be wrong-headed to close this and open something in nodejs/NG instead?