Proxy server built on envoy providing a REST gateway and the ability to translate gRPC-Web and/or Connect requests requests into regular gRPC requests. The Go binaries are available via GitHub Releases and we also provide a Docker image and a Nix package.
For most users, we recommend using our full distribution, which includes envoy.
docker run --rm -it -p 50052:50052 ghcr.io/mirkolenz/grpc-proxy:latest --proxy-port 50052 --backend-port 50051nix run github:mirkolenz/grpc-proxy#full -- --proxy-port 50052 --backend-port 50051For this type of installation, we assume that you have envoy installed on your system.
Please refer to the official documentation for instructions on how to install envoy.
If the envoy binary is not available in your $PATH, you can provide the path to the binary via the --envoy parameter.
First, install the binary:
go install github.com/mirkolenz/grpc-proxy@latestThen, run the proxy as follows:
grpc-proxy --envoy /usr/bin/envoy --proxy-port 50052 --backend-port 50051Go to the latest GitHub Release and download the binary for your platform for the list of assets. Then, run the proxy as follows:
./grpc-proxy --envoy /usr/bin/envoy --proxy-port 50052 --backend-port 50051nix run github:mirkolenz/grpc-proxy -- --proxy-port 50052 --backend-port 50051The gRPC-Web and Connect translation works without any additional configuration. The REST gateway requires the protobuf descriptor set as well as an explicit list of services to be exposed.
If you are already using buf, make sure to add buf.build/googleapis/googleapis to your deps.
Then, you can generate the descriptor set as follows:
buf build -o descriptor.binpbWhen using plain protoc, please refer to the official documentation.
Bear in mind that in case of using Docker, you need to mount the descriptor set into the container (e.g., -v $(pwd)/descriptor.binpb:/descriptor.binpb).
Afterwards, run the proxy as follows:
grpc-proxy --proxy-port 50052 --backend-port 50051 --rest-proto-descriptor "./descriptor.binpb" --rest-services "package1.ServiceA,package2.ServiceB"Usage: grpc-proxy --backend-port=BACKEND-PORT,... --proxy-port=INT [flags]
Flags:
-h, --help Show context-sensitive help.
--version Print version information.
--access-log=/dev/stdout,...
Access log files.
--envoy="envoy" Path to the envoy executable. If set to an empty
string, the config will only be printed.
Backend Options
--backend-host="127.0.0.1" Host address of the backend.
--backend-port=BACKEND-PORT,...
Port of the backend. Multiple can be provided to
enable load balancing via round robin.
--backend-timeout=120 Timeout in seconds for requests sent to the
backend.
Proxy Options
--proxy-host="127.0.0.1" Host address of the envoy proxy.
--proxy-port=INT Port of the envoy proxy.
Admin Options
--admin-host="127.0.0.1" Host address of the admin interface.
--admin-port=INT Port of the admin interface.
Cluster Options
--cluster-dns-lookup-family="V4_PREFERRED"
The DNS IP address resolution policy.
--cluster-load-balance-policy="ROUND_ROBIN"
The load balancer type to use when picking a host in the cluster.
--cluster-discovery-type="STRICT_DNS"
The service discovery type to use for resolving the cluster.
--cluster-connect-timeout=0.25
The timeout in seconds for new network connections to hosts in the
cluster.
--cluster-max-concurrent-streams=100
Maximum concurrent streams allowed for peer on one HTTP/2 connection.
REST Gateway Options
--rest-proto-descriptor=STRING
Supplies the filename of the proto descriptor
set for the gRPC services.
--rest-proto-descriptor-bin=STRING
Supplies the binary content of the proto
descriptor set for the gRPC services.
--rest-services=REST-SERVICES,...
A list of strings that supplies the
fully qualified service names (i.e.
“package_name.service_name”) that the
transcoder will translate. If the service
name doesn't exist in proto_descriptor, Envoy
will fail at startup. The proto_descriptor may
contain more services than the service names
specified here, but they won’t be translated.
By default, the filter will pass through
requests that do not map to any specified
services. If the list of services is empty,
filter is considered disabled. However,
this behavior changes if reject_unknown_method
is enabled.
--[no-]rest-auto-mapping Whether to route methods without the
google.api.http option.
--rest-convert-grpc-status Whether to convert gRPC status headers to
JSON. When trailer indicates a gRPC error and
there was no HTTP body, take google.rpc.Status
from the grpc-status-details-bin header
and use it as JSON body. If there was no
such header, make google.rpc.Status out of
the grpc-status and grpc-message headers.
The error details types must be present in the
proto_descriptor.
--rest-url-unescape-spec="ALL_CHARACTERS_EXCEPT_RESERVED"
URL unescaping policy. This spec is only
applied when extracting variable with multiple
segments in the URL path. For example,
in case of /foo/{x=*}/bar/{y=prefix/*}/{z=**}
x variable is single segment and y and
z are multiple segments. For a path with
/foo/first/bar/prefix/second/third/fourth,
x=first, y=prefix/second, z=third/fourth.
If this setting is not specified, the value
defaults to ALL_CHARACTERS_EXCEPT_RESERVED.
--rest-query-param-unescape-plus
If true, unescape + to space when extracting
variables in query parameters. This is to
support HTML 2.0
--rest-match-unregistered-custom-verb
If true, try to match the custom verb even
if it is unregistered. By default, only match
when it is registered. According to the http
template syntax, the custom verb is “:”
LITERAL at the end of http template.
--rest-case-insensitive-enum-parsin
Proto enum values are supposed to be in upper
cases when used in JSON. Set this to true if
your JSON request uses non uppercase enum
values.
--rest-max-request-body-size=10000000
The maximum size of a request body to be
transcoded, in bytes. A body exceeding this
size will provoke a HTTP 413 Request Entity
Too Large response. Large values may cause
envoy to use a lot of memory if there are many
concurrent requests.
--rest-max-response-body-size=10000000
The maximum size of a response body to be
transcoded, in bytes. A body exceeding this
size will provoke a HTTP 500 Internal Server
Error response. Large values may cause envoy
to use a lot of memory if there are many
concurrent requests.
--rest-ignore-unknown-query-parameters
Whether to ignore query parameters that cannot
be mapped to a corresponding protobuf field.
Use this if you cannot control the query
parameters and do not know them beforehand.
Otherwise use ignored_query_parameters.
Defaults to false.
--rest-ignored-query-parameters=REST-IGNORED-QUERY-PARAMETERS,...
A list of query parameters to be ignored
for transcoding method mapping. By default,
the transcoder filter will not transcode a
request if there are any unknown/invalid query
parameters.
--[no-]rest-add-whitespace Whether to add spaces, line breaks and
indentation to make the JSON output easy to
read. Defaults to true.
--rest-always-print-primitive-fields
Whether to always print primitive fields. By
default primitive fields with default values
will be omitted in JSON output. For example,
an int32 field set to 0 will be omitted.
Setting this flag to true will override the
default behavior and print primitive fields
regardless of their values. Defaults to false.
--rest-always-print-enums-as-ints
Whether to always print enums as ints.
By default they are rendered as strings.
Defaults to false.
--rest-preserve-proto-field-names
Whether to preserve proto field names.
By default protobuf will generate JSON field
names using the json_name option, or lower
camel case, in that order. Setting this flag
will preserve the original field names.
Defaults to false.
--rest-stream-newline-delimited
If true, return all streams as
newline-delimited JSON messages instead of as
a comma-separated array.
--rest-reject-unknown-method By default, a request that cannot be mapped to
any specified gRPC services will pass-through
this filter. When set to true, the request
will be rejected with a HTTP 404 Not Found.
--rest-reject-unknown-query-parameters
By default, a request with query parameters
that cannot be mapped to the gRPC request
message will pass-through this filter.
When set to true, the request will be rejected
with a HTTP 400 Bad Request.
--rest-reject-binding-body-field-collisions
If this field is set to true, the request will
be rejected if the binding value is different
from the body value.