[vtadmin] vschemas api endpoints

[ajm188]

Description

This PR adds the GetVSchema and GetVSchemas endpoints to vtadmin-api.

Related Issue(s)

• Closes Add GetVSchema(s) endpoints to vtadmin-api #7624

Checklist

• Should this PR be backported? no
• Tests were added or are not required
• Documentation was added or is not required

Deployment Notes

I've canaried this internally and looks good.

Impacted Areas in Vitess

Components that this PR will affect:

• Query Serving
• VReplication
• Cluster Management
• Build/CI
• VTAdmin

[doeg]

This looks great! Thank you so much!!

[doeg]

My one tiny + totally non-blocking comment is that I would have expected the field to be called vschema (no snake). 🐍

[ajm188]

Yeah, and this is my biggest issue with the protobuf/protoc toolchain, is I have no idea how to force it to name things in the generated code a particular way. If I don't snake case, then the field name in the generated Go code would be Vschema, when I want (because I would expect it to be) VSchema; the snake case forces the Go naming that I want, but it makes the typescript+json naming completely unintuitive. As far as I know, there's no way to have both (I'll do some more googling though!), and I'm naturally biased toward picking the "nice for Go" side because it's where I spend most of my time, but I could be convinced otherwise!

[doeg]

Ah that makes sense. The generated TypeScript types also turn out as VSchema which I agree looks best. 😎 Thanks for the explanation!

[ajm188]

I looked at this some more, and if I use just the natively available json_name extension:

diff --git a/proto/vtadmin.proto b/proto/vtadmin.proto
index 91a2939aa..7bf137793 100644
--- a/proto/vtadmin.proto
+++ b/proto/vtadmin.proto
@@ -106,7 +106,7 @@ message VSchema {
     Cluster cluster = 1;
     // Name is the name of the keyspace this VSchema is for.
     string name = 2;
-    vschema.Keyspace v_schema = 3;
+    vschema.Keyspace v_schema = 3 [json_name="vschema,omitempty"];
 }
 
 // Vtctld represents information about a single Vtctld host.
diff --git a/go/vt/proto/vtadmin/vtadmin.pb.go b/go/vt/proto/vtadmin/vtadmin.pb.go
index c897510cf..bfe1bb5a7 100644
--- a/go/vt/proto/vtadmin/vtadmin.pb.go
+++ b/go/vt/proto/vtadmin/vtadmin.pb.go
@@ -313,7 +313,7 @@ type VSchema struct {
        Cluster *Cluster `protobuf:"bytes,1,opt,name=cluster,proto3" json:"cluster,omitempty"`
        // Name is the name of the keyspace this VSchema is for.
        Name                 string            `protobuf:"bytes,2,opt,name=name,proto3" json:"name,o
mitempty"`
-       VSchema              *vschema.Keyspace `protobuf:"bytes,3,opt,name=v_schema,json=vSchema,pro
to3" json:"v_schema,omitempty"`
+       VSchema              *vschema.Keyspace `protobuf:"bytes,3,opt,name=v_schema,json=vschema,omi
tempty,proto3" json:"v_schema,omitempty"`
        XXX_NoUnkeyedLiteral struct{}          `json:"-"`
        XXX_unrecognized     []byte            `json:"-"`
        XXX_sizecache        int32             `json:"-"`

(Note that the json field within the protobuf struct tag changes, but the actual json struct tag does not).

However, apparently if we start relying on extensions only available using gogoproto's types, then this should work (stackoverflow post with example), but if I'm reading the takeaways from this discussion correctly, I think that's something vitess isn't quite comfortable committing to (yet?).

[rafael]

Merging based on review from @doeg