server.lua

-- Run from the repository root:
--   lua examples/helloworld/server.lua 127.0.0.1 50051

package.path = "./?.lua;./?/init.lua;examples/helloworld/?.lua;" .. package.path

local grpc = require("grpc")
local hello = require("helloworld_grpc")

local host = arg[1] or "127.0.0.1"
local port = tonumber(arg[2]) or 50051

assert(grpc.load_descriptor_set("examples/helloworld/helloworld.pb"))

local server = grpc.new_server({
    compression = os.getenv("GRPC_COMPRESSION"),
})
assert(hello.register_greeter_server(server, {
    say_hello = function(_, request)
        return { message = "Hello, " .. request.name .. "!" }
    end,
    watch_hello = function(_, request)
        local greetings = { "Hello", "Welcome", "Goodbye" }
        local index = 0
        return function()
            index = index + 1
            if greetings[index] == nil then
                return nil
            end
            return { message = greetings[index] .. ", " .. request.name .. "!" }
        end
    end,
    send_hello = function(_, stream)
        local count = 0
        while true do
            local request, recv_err = stream:recv()
            assert(not recv_err, tostring(recv_err))
            if not request then
                break
            end
            count = count + 1
        end
        return { message = string.format("Received %d greeting(s)", count) }
    end,
    chat = function(_, stream)
        while true do
            local request, recv_err = stream:recv()
            assert(not recv_err, tostring(recv_err))
            if not request then
                break
            end
            assert(stream:send({ message = "Echo: " .. request.name }))
        end
    end,
}))

assert(server:listen({
    host = host,
    port = port,
    insecure = true,
}))

print(string.format("Hello World gRPC server listening on %s:%d", host, port))
assert(server:loop())