fix(prometheus): disable features when prometheus plugin is turned off

apisix/plugin.lua

@@ -331,6 +331,8 @@ function _M.load(config)
         return local_plugins
     end
 
+    local exporter = require("apisix.plugins.prometheus.exporter")
+
     if ngx.config.subsystem == "http" then
         if not http_plugin_names then
             core.log.error("failed to read plugin list from local file")
@@ -344,6 +346,15 @@ function _M.load(config)
             if not ok then
                 core.log.error("failed to load plugins: ", err)
             end
+
+            local enabled = core.table.array_find(http_plugin_names, "prometheus") ~= nil
+            local active  = exporter.get_prometheus() ~= nil
+            if not enabled then
+                exporter.destroy()
+            end
+            if enabled and not active then
+                exporter.http_init()
+            end
         end
     end
 

apisix/plugins/prometheus/exporter.lua

@@ -28,6 +28,7 @@ local pcall = pcall
 local select = select
 local type = type
 local prometheus
+local prometheus_bkp
 local router = require("apisix.router")
 local get_routes = router.http_routes
 local get_ssls   = router.ssls
@@ -112,6 +113,9 @@ function _M.http_init(prometheus_enabled_in_stream)
     -- todo: support hot reload, we may need to update the lua-prometheus
     -- library
     if ngx.get_phase() ~= "init" and ngx.get_phase() ~= "init_worker"  then
+        if prometheus_bkp then
+            prometheus = prometheus_bkp
+        end
         return
     end
 
@@ -522,6 +526,9 @@ _M.get_api = get_api
 
 
 function _M.export_metrics(stream_only)
+    if not prometheus then
+        core.response.exit(200, "{}")
+    end
     local api = get_api(false)
     local uri = ngx.var.uri
     local method = ngx.req.get_method()
@@ -545,4 +552,13 @@ function _M.get_prometheus()
     return prometheus
 end
 
+
+function _M.destroy()
+    if prometheus ~= nil then
+        prometheus_bkp = core.table.deepcopy(prometheus)
+        prometheus = nil
+    end
+end
+
+
 return _M

t/cli/test_prometheus_reload.sh

@@ -0,0 +1,91 @@
+#!/usr/bin/env bash
+
+#
+# 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.
+#
+
+. ./t/cli/common.sh
+
+git checkout conf/config.yaml
+
+make run
+
+sleep 2
+
+echo "removing prometheus from the plugins list"
+echo '
+deployment:
+  role: traditional
+  role_traditional:
+    config_provider: etcd
+  admin:
+    admin_key: null
+apisix:
+  node_listen: 1984
+plugins:
+  - ip-restriction' > conf/config.yaml
+
+echo "fetch metrics, should not contain {}"
+
+if curl -i http://127.0.0.1:9091/apisix/prometheus/metrics | grep "{}" > /dev/null; then
+    echo "failed: metrics should not contain '{}' when prometheus is enabled"
+    exit 1
+fi
+
+echo "calling reload API to actually disable prometheus"
+
+curl -i http://127.0.0.1:9090/v1/plugins/reload -XPUT
+
+sleep 2
+
+echo "fetch metrics after reload should contain {}"
+
+if ! curl -i http://127.0.0.1:9091/apisix/prometheus/metrics | grep "{}" > /dev/null; then
+    echo "failed: metrics should contain '{}' when prometheus is disabled"
+    exit 1
+fi
+
+echo "re-enable prometheus"
+
+echo '
+deployment:
+  role: traditional
+  role_traditional:
+    config_provider: etcd
+  admin:
+    admin_key: null
+apisix:
+  node_listen: 1984
+plugins:
+  - prometheus' > conf/config.yaml
+
+echo "fetching metrics without reloading should give same result as before"
+
+if ! curl -i http://127.0.0.1:9091/apisix/prometheus/metrics | grep "{}" > /dev/null; then
+    echo "failed: metrics should contain '{}' when prometheus is disabled"
+    exit 1
+fi
+
+echo "calling reload API to actually enable prometheus"
+
+curl -i http://127.0.0.1:9090/v1/plugins/reload -XPUT
+
+sleep 2
+
+if curl -i http://127.0.0.1:9091/apisix/prometheus/metrics | grep "{}" > /dev/null; then
+    echo "failed: metrics should not contain '{}' when prometheus is enabled"
+    exit 1
+fi

t/plugin/prometheus4.t

@@ -277,3 +277,139 @@ apisix_http_latency_bucket\{type="upstream",route="1",service="",consumer="",nod
 apisix_http_latency_bucket\{type="upstream",route="1",service="",consumer="",node="127.0.0.1",le="105"\} \d+
 apisix_http_latency_bucket\{type="upstream",route="1",service="",consumer="",node="127.0.0.1",le="205"\} \d+
 apisix_http_latency_bucket\{type="upstream",route="1",service="",consumer="",node="127.0.0.1",le="505"\} \d+/
+
+
+
+=== TEST 10: set sys plugins
+--- config
+    location /t {
+        content_by_lua_block {
+            local t = require("lib.test_admin").test
+            local code, body = t('/apisix/admin/routes/9',
+                 ngx.HTTP_PUT,
+                 [[{
+                        "methods": ["GET"],
+                        "plugins": {
+                            "prometheus": {},
+                            "syslog": {
+                                "host": "127.0.0.1",
+                                "include_req_body": false,
+                                "max_retry_times": 1,
+                                "tls": false,
+                                "retry_interval": 1,
+                                "batch_max_size": 1000,
+                                "buffer_duration": 60,
+                                "port": 1000,
+                                "name": "sys-logger",
+                                "flush_limit": 4096,
+                                "sock_type": "tcp",
+                                "timeout": 3,
+                                "drop_limit": 1048576,
+                                "pool_size": 5
+                            }
+                        },
+                        "upstream": {
+                            "nodes": {
+                                "127.0.0.1:1980": 1
+                            },
+                            "type": "roundrobin"
+                        },
+                        "uri": "/batch-process-metrics"
+                }]]
+                )
+            if code >= 300 then
+                ngx.status = code
+            end
+            ngx.say(body)
+        }
+    }
+--- request
+GET /t
+--- response_body
+passed
+--- no_error_log
+[error]
+
+
+
+=== TEST 11: remove prometheus -> reload -> send batch request -> add prometheus for next tests
+--- config
+    location /t {
+        content_by_lua_block {
+            local http = require "resty.http"
+            local httpc = http.new()
+
+            local t = require("lib.test_admin").test
+            ngx.sleep(0.1)
+            local data = [[
+deployment:
+  role: traditional
+  role_traditional:
+    config_provider: etcd
+  admin:
+    admin_key: null
+apisix:
+  node_listen: 1984
+plugins:
+    - example-plugin
+plugin_attr:
+    example-plugin:
+        val: 1
+        ]]
+            require("lib.test_admin").set_config_yaml(data)
+            local code, _, org_body = t('/v1/plugins/reload', ngx.HTTP_PUT)
+            local code, body = t('/batch-process-metrics',
+                 ngx.HTTP_GET
+                )
+
+            ngx.status = code
+            ngx.say(body)
+
+            local data = [[
+deployment:
+  role: traditional
+  role_traditional:
+    config_provider: etcd
+  admin:
+    admin_key: null
+apisix:
+  node_listen: 1984
+plugins:
+    - prometheus
+plugin_attr:
+    example-plugin:
+        val: 1
+        ]]
+            require("lib.test_admin").set_config_yaml(data)
+        }
+    }
+--- request
+GET /t
+--- error_code: 404
+--- response_body_like eval
+qr/404 Not Found/
+
+
+
+=== TEST 12: fetch prometheus metrics -> batch_process_entries metrics should not be present
+--- request
+GET /apisix/prometheus/metrics
+--- error_code: 200
+--- response_body_unlike eval
+qr/apisix_batch_process_entries\{name="sys-logger",route_id="9",server_addr="127.0.0.1"\} \d+/
+
+
+
+=== TEST 13: hit batch-process-metrics with prometheus enabled from TEST 11
+--- request
+GET /batch-process-metrics
+--- error_code: 404
+
+
+
+=== TEST 14: batch_process_entries metrics should be present now
+--- request
+GET /apisix/prometheus/metrics
+--- error_code: 200
+--- response_body_like eval
+qr/apisix_batch_process_entries\{name="sys-logger",route_id="9",server_addr="127.0.0.1"\} \d+/