Copying in the Juju list also On 12/10/17 22:18, Ian Booth wrote: > I'd like to understand the use case you have in mind a little better. The > premise of the network-get output is that charms should not think about public > vs private addresses in terms of what to put into relation data - the other > remote unit should not be exposed to things in those terms. > > There's some doc here to explain things in more detail > > https://jujucharms.com/docs/master/developer-network-primitives > > The TL;DR: is that charms need to care about: > - what address do I bind to (listen on) > - what address do external actors use to connect to me (ingress) > > Depending on how the charm has been deployed, and more specifically whether it > is in a cross model relation, the ingress address might be either the public > or > private address. Juju will decide based on a number of factors (whether models > are deployed to same region, vpc, other provider specific aspects) and > populate > the network-get data accordingly. NOTE: for now Juju will always pick the > public > address (if there is one) for the ingress value for cross model relations - > the > algorithm to short circuit to a cloud local address is not yet finished. > > The content of the bind-addresses block is space aware in that these are > filtered based on the space with which the specified endpoint is associated. > The > network-get output though should not include any space information explicitly > - > this is a concern which a charm should not care about. > > > On 12/10/17 13:35, James Beedy wrote: >> Hello all, >> >> In case you haven't noticed, we now have a network_get() function available >> in charmhelpers.core.hookenv (in master, not stable). >> >> Just wanted to have a little discussion about how we are going to be >> parsing network_get(). >> >> I first want to address the output of network_get() for an instance >> deployed to the default vpc, no spaces constraint, and related to another >> instance in another model also default vpc, no spaces constraint. >> >> {'ingress-addresses': ['107.22.129.65'], 'bind-addresses': [{'addresses': >> [{'cidr': '172.31.48.0/20', 'address': '172.31.51.59'}], 'interfacename': >> 'eth0', 'macaddress': '12:ba:53:58:9c:52'}, {'addresses': [{'cidr': ' >> 252.48.0.0/12', 'address': '252.51.59.1'}], 'interfacename': 'fan-252', >> 'macaddress': '1e:a2:1e:96:ec:a2'}]} >> >> >> The use case I have in mind here is such that I want to provide the private >> network interface address via relation data in the provides.py of my >> interface to the relating appliication. >> >> This will be able to happen by calling >> hookenv.network_get('<interface-name>') in the layer that provides the >> interface in my charm, and passing the output to get the private interface >> ip data, to then set that in the provides side of the relation. >> >> Tracking? >> >> The problem: >> >> The problem is such that its not so straight forward to just get the >> private address from the output of network_get(). >> >> As you can see above, I could filter for network interface name, but thats >> about the least best way one could go about this. >> >> Initially, I assumed the network_get() output would look different if you >> had specified a spaces constraint when deploying your application, but the >> output was similar to no spaces, e.g. spaces aren't listed in the output of >> network_get(). >> >> >> All in all, what I'm after is a consistent way to grep either the space an >> interface is bound to, or to get the public vs private address from the >> output of network_get(), I think this is true for every provider just about >> (ones that use spaces at least). >> >> Instead of the dict above, I was thinking we might namespace the interfaces >> inside of what type of interface they are to make it easier to decipher >> when parsing the network_get(). >> >> My idea is a schema like the following: >> >> { >> 'private-networks': { >> 'my-admin-space': { >> 'addresses': [ >> { >> 'cidr': '172.31.48.0/20', >> 'address': '172.31.51.59' >> } >> ], >> 'interfacename': 'eth0', >> 'macaddress': '12:ba:53:58:9c:52' >> } >> 'public-networks': { >> 'default': { >> 'addresses': [ >> { >> 'cidr': 'publicipaddress/32', >> 'address': 'publicipaddress' >> } >> ], >> } >> 'fan-networks': { >> 'fan-252': { >> .... >> .... >> } >> } >> >> Where all interfaces bound to spaces are considered private addresses, and >> with the assumption that if you don't specify a space constraint, your >> private network interface is bound to the "default" space. >> >> The key thing here is the schema structure grouping the interfaces bound to >> spaces inside a private-networks level in the dict, and the introduction of >> the fact that if you don't specify a space, you get an address bound to an >> artificial "default" space. >> >> I feel this would make things easier to consume, and interface to from a >> developer standpoint. >> >> Is this making sense? How do others feel? >> >> >> >
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