When traversing an exported peered service, the discovery chain
evaluation at the other side may re-route the request to a variety of
endpoints. Furthermore we intend to terminate mTLS at the mesh gateway
for arriving peered traffic that is http-like (L7), so the caller needs
to know the mesh gateway's SpiffeID in that case as well.
The following new SpiffeID values will be shipped back in the peerstream
replication:
- tcp: all possible SpiffeIDs resulting from the service-resolver
component of the exported discovery chain
- http-like: the SpiffeID of the mesh gateway
Mesh gateways will now enable tcp connections with SNI names including peering information so that those connections may be proxied.
Note: this does not change the callers to use these mesh gateways.
Given that the exported-services config entry can use wildcards, the
precedence for wildcards is handled as with intentions. The most exact
match is the match that applies for any given service. We do not take
the union of all that apply.
Another update that was made was to reflect that only one
exported-services config entry applies to any given service in a
partition. This is a pre-existing constraint that gets enforced by
the Normalize() method on that config entry type.
The importing peer will need to know what SNI and SPIFFE name
corresponds to each exported service. Additionally it will need to know
at a high level the protocol in use (L4/L7) to generate the appropriate
connection pool and local metrics.
For replicated connect synthetic entities we edit the `Connect{}` part
of a `NodeService` to have a new section:
{
"PeerMeta": {
"SNI": [
"web.default.default.owt.external.183150d5-1033-3672-c426-c29205a576b8.consul"
],
"SpiffeID": [
"spiffe://183150d5-1033-3672-c426-c29205a576b8.consul/ns/default/dc/dc1/svc/web"
],
"Protocol": "tcp"
}
}
This data is then replicated and saved as-is at the importing side. Both
SNI and SpiffeID are slices for now until I can be sure we don't need
them for how mesh gateways will ultimately work.
Treat each exported service as a "discovery chain" and replicate one
synthetic CheckServiceNode for each chain and remote mesh gateway.
The health will be a flattened generated check of the checks for that
mesh gateway node.
R.B. Boyer