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b4f49a55a5
The schwag was introduced to generate swagger with authorization support [1][1] in 2017. And in 2018, the grpc-gateway supports to render security fields by protoc-gen-swagger [2][2]. After several years, I think it's good to use upstream protoc supports. NOTE: The json's key in `rpc.swagger.json` has been reordered so that it seems that there's a lot of changes. How to verify it: ```bash $ # use jq -S to sort the key $ latest_commit="https://raw.githubusercontent.com/etcd-io/etcd/228f493c7697ce3e9d3a1d831bcffad175846c75/Documentation/dev-guide/apispec/swagger/rpc.swagger.json" $ curl -s "${latest_commit}" | jq -S . > /tmp/old.json $ cat Documentation/dev-guide/apispec/swagger/rpc.swagger.json | jq -S . > /tmp/new.json $ diff --color -u /tmp/old.json /tmp/new.json ``` ```diff --- /tmp/old.json 2023-04-26 10:58:07.142311861 +0800 +++ /tmp/new.json 2023-04-26 10:58:12.170299194 +0800 @@ -1523,11 +1523,14 @@ "type": "object" }, "protobufAny": { + "description": "`Any` contains an arbitrary serialized protocol buffer message along with a\nURL that describes the type of the serialized message.\n\nProtobuf library provides support to pack/unpack Any values in the form\nof utility functions or additional generated methods of the Any type.\n\nExample 1: Pack and unpack a message in C++.\n\n Foo foo = ...;\n Any any;\n any.PackFrom(foo);\n ...\n if (any.UnpackTo(&foo)) {\n ...\n }\n\nExample 2: Pack and unpack a message in Java.\n\n Foo foo = ...;\n Any any = Any.pack(foo);\n ...\n if (any.is(Foo.class)) {\n foo = any.unpack(Foo.class);\n }\n\n Example 3: Pack and unpack a message in Python.\n\n foo = Foo(...)\n any = Any()\n any.Pack(foo)\n ...\n if any.Is(Foo.DESCRIPTOR):\n any.Unpack(foo)\n ...\n\n Example 4: Pack and unpack a message in Go\n\n foo := &pb.Foo{...}\n any, err := ptypes.MarshalAny(foo)\n ...\n foo := &pb.Foo{}\n if err := ptypes.UnmarshalAny(any, foo); err != nil {\n ...\n }\n\nThe pack methods provided by protobuf library will by default use\n'type.googleapis.com/full.type.name' as the type URL and the unpack\nmethods only use the fully qualified type name after the last '/'\nin the type URL, for example \"foo.bar.com/x/y.z\" will yield type\nname \"y.z\".\n\n\nJSON\n====\nThe JSON representation of an `Any` value uses the regular\nrepresentation of the deserialized, embedded message, with an\nadditional field `@type` which contains the type URL. Example:\n\n package google.profile;\n message Person {\n string first_name = 1;\n string last_name = 2;\n }\n\n {\n \"@type\": \"type.googleapis.com/google.profile.Person\",\n \"firstName\": <string>,\n \"lastName\": <string>\n }\n\nIf the embedded message type is well-known and has a custom JSON\nrepresentation, that representation will be embedded adding a field\n`value` which holds the custom JSON in addition to the `@type`\nfield. Example (for message [google.protobuf.Duration][]):\n\n {\n \"@type\": \"type.googleapis.com/google.protobuf.Duration\",\n \"value\": \"1.212s\"\n }", "properties": { "type_url": { + "description": "A URL/resource name that uniquely identifies the type of the serialized\nprotocol buffer message. This string must contain at least\none \"/\" character. The last segment of the URL's path must represent\nthe fully qualified name of the type (as in\n`path/google.protobuf.Duration`). The name should be in a canonical form\n(e.g., leading \".\" is not accepted).\n\nIn practice, teams usually precompile into the binary all types that they\nexpect it to use in the context of Any. However, for URLs which use the\nscheme `http`, `https`, or no scheme, one can optionally set up a type\nserver that maps type URLs to message definitions as follows:\n\n* If no scheme is provided, `https` is assumed.\n* An HTTP GET on the URL must yield a [google.protobuf.Type][]\n value in binary format, or produce an error.\n* Applications are allowed to cache lookup results based on the\n URL, or have them precompiled into a binary to avoid any\n lookup. Therefore, binary compatibility needs to be preserved\n on changes to types. (Use versioned type names to manage\n breaking changes.)\n\nNote: this functionality is not currently available in the official\nprotobuf release, and it is not used for type URLs beginning with\ntype.googleapis.com.\n\nSchemes other than `http`, `https` (or the empty scheme) might be\nused with implementation specific semantics.", "type": "string" }, "value": { + "description": "Must be a valid serialized protocol buffer of the above specified type.", "format": "byte", "type": "string" } ``` REF: 1: <https://github.com/etcd-io/etcd/pull/7999#issuecomment-307512043> 2: <https://github.com/grpc-ecosystem/grpc-gateway/pull/547> Signed-off-by: Wei Fu <fuweid89@gmail.com>
etcd/client/v3
etcd/clientv3 is the official Go etcd client for v3.
Install
go get go.etcd.io/etcd/client/v3
Get started
Create client using clientv3.New:
import clientv3 "go.etcd.io/etcd/client/v3"
func main() {
cli, err := clientv3.New(clientv3.Config{
Endpoints: []string{"localhost:2379", "localhost:22379", "localhost:32379"},
DialTimeout: 5 * time.Second,
})
if err != nil {
// handle error!
}
defer cli.Close()
}
etcd v3 uses gRPC for remote procedure calls. And clientv3 uses
grpc-go to connect to etcd. Make sure to close the client after using it.
If the client is not closed, the connection will have leaky goroutines. To specify client request timeout,
pass context.WithTimeout to APIs:
ctx, cancel := context.WithTimeout(context.Background(), timeout)
resp, err := cli.Put(ctx, "sample_key", "sample_value")
cancel()
if err != nil {
// handle error!
}
// use the response
For full compatibility, it is recommended to install released versions of clients using go modules.
Error Handling
etcd client returns 2 types of errors:
- context error: canceled or deadline exceeded.
- gRPC error: see api/v3rpc/rpctypes.
Here is the example code to handle client errors:
resp, err := cli.Put(ctx, "", "")
if err != nil {
switch err {
case context.Canceled:
log.Fatalf("ctx is canceled by another routine: %v", err)
case context.DeadlineExceeded:
log.Fatalf("ctx is attached with a deadline is exceeded: %v", err)
case rpctypes.ErrEmptyKey:
log.Fatalf("client-side error: %v", err)
default:
log.Fatalf("bad cluster endpoints, which are not etcd servers: %v", err)
}
}
Metrics
The etcd client optionally exposes RPC metrics through go-grpc-prometheus. See the examples.
Namespacing
The namespace package provides clientv3 interface wrappers to transparently isolate client requests to a user-defined prefix.
Request size limit
Client request size limit is configurable via clientv3.Config.MaxCallSendMsgSize and MaxCallRecvMsgSize in bytes. If none given, client request send limit defaults to 2 MiB including gRPC overhead bytes. And receive limit defaults to math.MaxInt32.