feat: support proxying via unix socket

api_v3.md

@@ -46,6 +46,7 @@ Method
   - `serializer`: string - serializer type, default `json`, also support `raw` to keep origin string value.
   - `extra_headers`: table - adding custom headers for etcd requests.
   - `sni`: string - adding custom SNI fot etcd TLS requests.
+  - `unix_socket_proxy`: string - the unix socket path which will be used to proxy the etcd request.
 
 The client method returns either a `etcd` object or an `error string`.
 

lib/resty/etcd/v3.lua

@@ -14,6 +14,7 @@ local str_byte      = string.byte
 local str_char      = string.char
 local ipairs        = ipairs
 local pairs         = pairs
+local unpack        = unpack
 local re_match      = ngx.re.match
 local type          = type
 local tab_insert    = table.insert
@@ -56,6 +57,60 @@ local function choose_endpoint(self)
 end
 
 
+local function request_uri_via_unix_socket(self, uri, params)
+    local parsed_uri, err = self:parse_uri(uri, false)
+    if not parsed_uri then
+        return nil, err
+    end
+
+    local path, query
+    params.scheme, params.host, params.port, path, query = unpack(parsed_uri)
+    if params.unix_socket_proxy then
+        if not params.headers then
+            params.headers = {}
+        end
+
+        params.headers["Host"] = params.host
+        params.host = params.unix_socket_proxy
+        params.port = nil
+    end
+
+    params.path = params.path or path
+    params.query = params.query or query
+    params.ssl_server_name = params.ssl_server_name or params.host
+
+    local res
+    res, err = self:connect(params)
+    if not res then
+        return nil, err
+    end
+
+    res, err = self:request(params)
+    if not res then
+        self:close()
+        return nil, err
+    end
+
+    local body
+    body, err = res:read_body()
+    if not body then
+        self:close()
+        return nil, err
+    end
+
+    res.body = body
+
+    if params.keepalive == false then
+        self:close()
+
+    else
+        self:set_keepalive(params.keepalive_timeout, params.keepalive_pool)
+    end
+
+    return res, nil
+end
+
+
 local function http_request_uri(self, http_cli, method, uri, body, headers, keepalive)
     local endpoint, err = choose_endpoint(self)
     if not endpoint then
@@ -70,7 +125,7 @@ local function http_request_uri(self, http_cli, method, uri, body, headers, keep
     end
 
     local res
-    res, err = http_cli:request_uri(full_uri, {
+    res, err = request_uri_via_unix_socket(http_cli, full_uri, {
         method = method,
         body = body,
         headers = headers,
@@ -79,6 +134,7 @@ local function http_request_uri(self, http_cli, method, uri, body, headers, keep
         ssl_cert_path = self.ssl_cert_path,
         ssl_key_path = self.ssl_key_path,
         ssl_server_name = self.sni,
+        unix_socket_proxy = self.unix_socket_proxy,
     })
 
     if err then
@@ -199,6 +255,7 @@ function _M.new(opts)
     local serializer = opts.serializer
     local extra_headers = opts.extra_headers
     local sni        = opts.sni
+    local unix_socket_proxy = opts.unix_socket_proxy
 
     if not typeof.uint(timeout) then
         return nil, 'opts.timeout must be unsigned integer'
@@ -228,6 +285,10 @@ function _M.new(opts)
         return nil, 'opts.password must be string or ignore'
     end
 
+    if unix_socket_proxy and not typeof.string(unix_socket_proxy) then
+        return nil, 'opts.unix_socket_proxy must be string or ignore'
+    end
+
     local endpoints = {}
     local http_hosts
     if type(http_host) == 'string' then -- signle node
@@ -243,12 +304,25 @@ function _M.new(opts)
             return nil, "invalid http host: " .. host .. ", err: " .. (err or "not matched")
         end
 
+        local addr
+        if unix_socket_proxy then
+            addr = unix_socket_proxy
+        else
+            addr = m[2] or "127.0.0.1"
+        end
+
+        local port
+        if not unix_socket_proxy then
+            port = m[3] or "2379"
+        end
+
         tab_insert(endpoints, {
             full_prefix = host .. utils.normalize(api_prefix),
             http_host   = host,
             scheme      = m[1],
             host        = m[2] or "127.0.0.1",
-            port        = m[3] or "2379",
+            address     = addr,
+            port        = port,
             api_prefix  = api_prefix,
         })
     end
@@ -282,6 +356,7 @@ function _M.new(opts)
             ssl_key_path = opts.ssl_key_path,
             extra_headers = extra_headers,
             sni        = sni,
+            unix_socket_proxy = unix_socket_proxy,
         },
         mt)
 end
@@ -581,7 +656,7 @@ local function http_request_chunk(self, http_cli)
     local ok
     ok, err = http_cli:connect({
         scheme = endpoint.scheme,
-        host = endpoint.host,
+        host = endpoint.address,
         port = endpoint.port,
         ssl_verify = self.ssl_verify,
         ssl_cert_path = self.ssl_cert_path,
@@ -668,6 +743,10 @@ local function request_chunk(self, method, path, opts, timeout)
         return nil, err
     end
 
+    if self.unix_socket_proxy then
+        headers["Host"] = endpoint.host
+    end
+
     local res
     res, err = http_cli:request({
         method  = method,

t/v3/unix_socket.t

@@ -0,0 +1,128 @@
+use Test::Nginx::Socket::Lua;
+
+log_level('info');
+no_long_string();
+repeat_each(1);
+
+my $test_dir = html_dir();
+$ENV{TEST_NGINX_HTML_DIR} ||= $test_dir;
+
+my $etcd_version = `etcd --version`;
+if ($etcd_version =~ /^etcd Version: 2/ || $etcd_version =~ /^etcd Version: 3.1./) {
+    plan(skip_all => "etcd is too old, skip v3 protocol");
+} else {
+    plan 'no_plan';
+}
+
+our $HttpConfig = <<"_EOC_";
+    lua_socket_log_errors off;
+    lua_package_path 'lib/?.lua;/usr/local/share/lua/5.1/?.lua;;';
+    init_by_lua_block {
+        local cjson = require("cjson.safe")
+
+        function check_res(data, err, val, status)
+            if err then
+                ngx.say("err: ", err)
+                ngx.exit(200)
+            end
+
+            if val then
+                if data and data.body.kvs==nil then
+                    ngx.exit(404)
+                end
+                if data and data.body.kvs and val ~= data.body.kvs[1].value then
+                    ngx.say("failed to check value")
+                    ngx.log(ngx.ERR, "failed to check value, got: ", data.body.kvs[1].value,
+                            ", expect: ", val)
+                    ngx.exit(200)
+                else
+                    ngx.say("checked val as expect: ", val)
+                end
+            end
+
+            if status and status ~= data.status then
+                ngx.exit(data.status)
+            end
+        end
+    }
+
+    server {
+        listen unix:$test_dir/lua-resty-etcd.sock;
+        location / {
+            access_by_lua_block {
+                ngx.log(ngx.WARN, "hit with host ", ngx.var.http_host)
+            }
+            proxy_pass http://127.0.0.1:2379;
+            proxy_http_version 1.1;
+            proxy_set_header Connection "";
+            proxy_set_header Host \$http_host;
+        }
+    }
+_EOC_
+
+run_tests();
+
+__DATA__
+
+=== TEST 1: request over unix socket
+--- http_config eval: $::HttpConfig
+--- config
+    location /t {
+        content_by_lua_block {
+            local etcd, err = require("resty.etcd").new({protocol = "v3", unix_socket_proxy = "unix:$TEST_NGINX_HTML_DIR/lua-resty-etcd.sock"})
+            check_res(etcd, err)
+
+            local res, err = etcd:set("/test", "abc")
+            check_res(res, err)
+
+            ngx.timer.at(0.1, function ()
+                etcd:set("/test", "bcd3")
+            end)
+
+            ngx.timer.at(0.2, function ()
+                etcd:set("/test", "bcd4")
+            end)
+
+            local cur_time = ngx.now()
+            local body_chunk_fun, err, http_cli = etcd:watch("/test", {timeout = 0.5, need_cancel = true})
+
+            if type(http_cli) ~= "table" then
+                ngx.say("need_cancel failed")
+            end
+
+            if not body_chunk_fun then
+                ngx.say("failed to watch: ", err)
+            end
+
+            local chunk, err = body_chunk_fun()
+            ngx.say("created: ", chunk.result.created)
+            local chunk, err = body_chunk_fun()
+            ngx.say("value: ", chunk.result.events[1].kv.value)
+
+            local res, err = etcd:watchcancel(http_cli)
+            if not res then
+                ngx.say("failed to cancel: ", err)
+            end
+
+            local chunk, err = body_chunk_fun()
+            ngx.say(err)
+
+            ngx.say("ok")
+        }
+    }
+--- request
+GET /t
+--- no_error_log
+[error]
+--- grep_error_log eval
+qr/hit with host 127.0.0.1/
+--- grep_error_log_out
+hit with host 127.0.0.1
+hit with host 127.0.0.1
+hit with host 127.0.0.1
+--- response_body
+created: true
+value: bcd3
+closed
+ok
+--- timeout: 5