feat: stream subsystem support consul_kv service discovery (#8633)

Fixes #7779

Author: ronething

docs/en/latest/discovery/consul_kv.md

@@ -131,6 +131,8 @@ To avoid confusion, use the full consul key url path as service name in practice
 
 ### Upstream setting
 
+#### L7
+
 Here is an example of routing a request with a URL of "/*" to a service which named "http://127.0.0.1:8500/v1/kv/upstreams/webpages/" and use consul_kv discovery client in the registry :
 
 ```shell
@@ -172,6 +174,25 @@ The format response as below:
 
 You could find more usage in the `apisix/t/discovery/consul_kv.t` file.
 
+#### L4
+
+Consul_kv service discovery also supports use in L4, the configuration method is similar to L7.
+
+```shell
+$ curl http://127.0.0.1:9180/apisix/admin/stream_routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -i -d '
+{
+    "remote_addr": "127.0.0.1",
+    "upstream": {
+      "scheme": "tcp",
+      "service_name": "http://127.0.0.1:8500/v1/kv/upstreams/webpages/",
+      "type": "roundrobin",
+      "discovery_type": "consul_kv"
+    }
+}'
+```
+
+You could find more usage in the `apisix/t/discovery/stream/consul_kv.t` file.
+
 ## Debugging API
 
 It also offers control api for debugging.

t/discovery/stream/consul_kv.t

@@ -0,0 +1,269 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+use t::APISIX 'no_plan';
+
+repeat_each(1);
+log_level('info');
+no_root_location();
+no_shuffle();
+
+
+add_block_preprocessor(sub {
+    my ($block) = @_;
+
+    my $http_config = $block->http_config // <<_EOC_;
+
+    server {
+        listen 20999;
+
+        location / {
+            content_by_lua_block {
+                ngx.say("missing consul_kv services")
+            }
+        }
+    }
+
+    server {
+        listen 30511;
+
+        location /hello {
+            content_by_lua_block {
+                ngx.say("server 1")
+            }
+        }
+    }
+    server {
+        listen 30512;
+
+        location /hello {
+            content_by_lua_block {
+                ngx.say("server 2")
+            }
+        }
+    }
+    server {
+        listen 30513;
+
+        location /hello {
+            content_by_lua_block {
+                ngx.say("server 3")
+            }
+        }
+    }
+    server {
+        listen 30514;
+
+        location /hello {
+            content_by_lua_block {
+                ngx.say("server 4")
+            }
+        }
+    }
+_EOC_
+
+    $block->set_value("http_config", $http_config);
+
+    if (!$block->stream_request) {
+        $block->set_value("stream_request", "GET /hello HTTP/1.1\r\nHost: 127.0.0.1:1985\r\nConnection: close\r\n\r\n");
+    }
+});
+
+our $yaml_config = <<_EOC_;
+apisix:
+  node_listen: 1984
+deployment:
+  role: data_plane
+  role_data_plane:
+    config_provider: yaml
+discovery:
+  consul_kv:
+    servers:
+      - "http://127.0.0.1:8500"
+      - "http://127.0.0.1:8600"
+    prefix: "upstreams"
+    skip_keys:
+      - "upstreams/unused_api/"
+    timeout:
+      connect: 1000
+      read: 1000
+      wait: 60
+    weight: 1
+    fetch_interval: 1
+    keepalive: true
+    default_service:
+      host: "127.0.0.1"
+      port: 20999
+      metadata:
+        fail_timeout: 1
+        weight: 1
+        max_fails: 1
+_EOC_
+
+
+run_tests();
+
+__DATA__
+
+=== TEST 1: prepare consul kv register nodes
+--- config
+location /consul1 {
+    rewrite  ^/consul1/(.*) /v1/kv/$1 break;
+    proxy_pass http://127.0.0.1:8500;
+}
+
+location /consul2 {
+    rewrite  ^/consul2/(.*) /v1/kv/$1 break;
+    proxy_pass http://127.0.0.1:8600;
+}
+--- pipelined_requests eval
+[
+    "DELETE /consul1/upstreams/webpages/?recurse=true",
+    "DELETE /consul2/upstreams/webpages/?recurse=true",
+    "PUT /consul1/upstreams/webpages/127.0.0.1:30511\n" . "{\"weight\": 1, \"max_fails\": 2, \"fail_timeout\": 1}",
+    "PUT /consul1/upstreams/webpages/127.0.0.1:30512\n" . "{\"weight\": 1, \"max_fails\": 2, \"fail_timeout\": 1}",
+    "PUT /consul2/upstreams/webpages/127.0.0.1:30513\n" . "{\"weight\": 1, \"max_fails\": 2, \"fail_timeout\": 1}",
+    "PUT /consul2/upstreams/webpages/127.0.0.1:30514\n" . "{\"weight\": 1, \"max_fails\": 2, \"fail_timeout\": 1}",
+]
+--- response_body eval
+["true", "true", "true", "true", "true", "true"]
+
+
+
+=== TEST 2: test consul server 1
+--- yaml_config eval: $::yaml_config
+--- apisix_yaml
+stream_routes:
+  - server_addr: 127.0.0.1
+    server_port: 1985
+    id: 1
+    upstream:
+      service_name: http://127.0.0.1:8500/v1/kv/upstreams/webpages/
+      discovery_type: consul_kv
+      type: roundrobin
+#END
+--- stream_response eval
+qr/server [1-2]/
+--- no_error_log
+[error]
+
+
+
+=== TEST 3: test consul server 2
+--- yaml_config eval: $::yaml_config
+--- apisix_yaml
+stream_routes:
+  - server_addr: 127.0.0.1
+    server_port: 1985
+    id: 1
+    upstream:
+      service_name: http://127.0.0.1:8600/v1/kv/upstreams/webpages/
+      discovery_type: consul_kv
+      type: roundrobin
+#END
+--- stream_response eval
+qr/server [3-4]/
+--- no_error_log
+[error]
+
+
+
+=== TEST 4: test mini consul_kv config
+--- yaml_config
+apisix:
+  node_listen: 1984
+deployment:
+  role: data_plane
+  role_data_plane:
+    config_provider: yaml
+discovery:
+  consul_kv:
+    servers:
+      - "http://127.0.0.1:8500"
+      - "http://127.0.0.1:6500"
+#END
+--- apisix_yaml
+stream_routes:
+  - server_addr: 127.0.0.1
+    server_port: 1985
+    id: 1
+    upstream:
+      service_name: http://127.0.0.1:8500/v1/kv/upstreams/webpages/
+      discovery_type: consul_kv
+      type: roundrobin
+#END
+--- stream_response eval
+qr/server [1-2]/
+--- ignore_error_log
+
+
+
+=== TEST 5: test invalid service name
+sometimes the consul key maybe deleted by mistake
+--- yaml_config eval: $::yaml_config
+--- apisix_yaml
+stream_routes:
+  - server_addr: 127.0.0.1
+    server_port: 1985
+    id: 1
+    upstream:
+      service_name: http://127.0.0.1:8600/v1/kv/upstreams/deleted_keys/
+      discovery_type: consul_kv
+      type: roundrobin
+#END
+--- stream_response_like
+missing consul_kv services
+--- ignore_error_log
+
+
+
+=== TEST 6: test skip keys
+skip some keys, return default nodes, get response: missing consul_kv services
+--- yaml_config
+apisix:
+  node_listen: 1984
+deployment:
+  role: data_plane
+  role_data_plane:
+    config_provider: yaml
+discovery:
+  consul_kv:
+    servers:
+      - "http://127.0.0.1:8600"
+    prefix: "upstreams"
+    skip_keys:
+      - "upstreams/webpages/"
+    default_service:
+      host: "127.0.0.1"
+      port: 20999
+      metadata:
+        fail_timeout: 1
+        weight: 1
+        max_fails: 1
+#END
+--- apisix_yaml
+stream_routes:
+  - server_addr: 127.0.0.1
+    server_port: 1985
+    id: 1
+    upstream:
+      service_name: http://127.0.0.1:8600/v1/kv/upstreams/webpages/
+      discovery_type: consul_kv
+      type: roundrobin
+#END
+--- stream_response_like
+missing consul_kv services
+--- ignore_error_log