feat: ai-content-moderation plugin (apache#11541)

Makefile

@@ -377,6 +377,10 @@ install: runtime
 	$(ENV_INSTALL) -d $(ENV_INST_LUADIR)/apisix/plugins/ai-proxy/drivers
 	$(ENV_INSTALL) apisix/plugins/ai-proxy/drivers/*.lua $(ENV_INST_LUADIR)/apisix/plugins/ai-proxy/drivers
 
+	# ai-content-moderation plugin
+	$(ENV_INSTALL) -d $(ENV_INST_LUADIR)/apisix/plugins/ai
+	$(ENV_INSTALL) apisix/plugins/ai/*.lua $(ENV_INST_LUADIR)/apisix/plugins/ai
+
 	$(ENV_INSTALL) bin/apisix $(ENV_INST_BINDIR)/apisix
 
 

apisix-master-0.rockspec

@@ -82,7 +82,7 @@ dependencies = {
     "lua-resty-t1k = 1.1.5",
     "brotli-ffi = 0.3-1",
     "lua-ffi-zlib = 0.6-0",
-    "api7-lua-resty-aws == 2.0.1-1",
+    "api7-lua-resty-aws == 2.0.2-1",
 }
 
 build = {

apisix/cli/config.lua

@@ -216,6 +216,7 @@ local _M = {
     "body-transformer",
     "ai-prompt-template",
     "ai-prompt-decorator",
+    "ai-content-moderation",
     "proxy-mirror",
     "proxy-rewrite",
     "workflow",

apisix/plugins/ai-content-moderation.lua

@@ -0,0 +1,179 @@
+--
+-- 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.
+--
+local core = require("apisix.core")
+local aws_instance = require("resty.aws")()
+local http = require("resty.http")
+local fetch_secrets = require("apisix.secret").fetch_secrets
+
+local next = next
+local pairs = pairs
+local unpack = unpack
+local type = type
+local ipairs = ipairs
+local require = require
+local HTTP_INTERNAL_SERVER_ERROR = ngx.HTTP_INTERNAL_SERVER_ERROR
+local HTTP_BAD_REQUEST = ngx.HTTP_BAD_REQUEST
+
+
+local aws_comprehend_schema = {
+    type = "object",
+    properties = {
+        access_key_id = { type = "string" },
+        secret_access_key = { type = "string" },
+        region = { type = "string" },
+        endpoint = {
+            type = "string",
+            pattern = [[^https?://]]
+        },
+        ssl_verify = {
+            type = "boolean",
+            default = true
+        }
+    },
+    required = { "access_key_id", "secret_access_key", "region", }
+}
+
+local moderation_categories_pattern = "^(PROFANITY|HATE_SPEECH|INSULT|"..
+                                      "HARASSMENT_OR_ABUSE|SEXUAL|VIOLENCE_OR_THREAT)$"
+local schema = {
+    type = "object",
+    properties = {
+        provider = {
+            type = "object",
+            properties = {
+                aws_comprehend = aws_comprehend_schema
+            },
+            maxProperties = 1,
+            -- ensure only one provider can be configured while implementing support for
+            -- other providers
+            required = { "aws_comprehend" }
+        },
+        moderation_categories = {
+            type = "object",
+            patternProperties = {
+                [moderation_categories_pattern] = {
+                    type = "number",
+                    minimum = 0,
+                    maximum = 1
+                }
+            },
+            additionalProperties = false
+        },
+        moderation_threshold = {
+            type = "number",
+            minimum = 0,
+            maximum = 1,
+            default = 0.5
+        },
+        llm_provider = {
+            type = "string",
+            enum = { "openai" },
+        }
+    },
+    required = { "provider", "llm_provider" },
+}
+
+
+local _M = {
+    version  = 0.1,
+    priority = 1040, -- TODO: might change
+    name     = "ai-content-moderation",
+    schema   = schema,
+}
+
+
+function _M.check_schema(conf)
+    return core.schema.check(schema, conf)
+end
+
+
+function _M.rewrite(conf, ctx)
+    conf = fetch_secrets(conf, true, conf, "")
+    if not conf then
+        return HTTP_INTERNAL_SERVER_ERROR, "failed to retrieve secrets from conf"
+    end
+
+    local body, err = core.request.get_json_request_body_table()
+    if not body then
+        return HTTP_BAD_REQUEST, err
+    end
+
+    local msgs = body.messages
+    if type(msgs) ~= "table" or #msgs < 1 then
+        return HTTP_BAD_REQUEST, "messages not found in request body"
+    end
+
+    local provider = conf.provider[next(conf.provider)]
+
+    local credentials = aws_instance:Credentials({
+        accessKeyId = provider.access_key_id,
+        secretAccessKey = provider.secret_access_key,
+        sessionToken = provider.session_token,
+    })
+
+    local default_endpoint = "https://comprehend." .. provider.region .. ".amazonaws.com"
+    local scheme, host, port = unpack(http:parse_uri(provider.endpoint or default_endpoint))
+    local endpoint = scheme .. "://" .. host
+    aws_instance.config.endpoint = endpoint
+    aws_instance.config.ssl_verify = provider.ssl_verify
+
+    local comprehend = aws_instance:Comprehend({
+        credentials = credentials,
+        endpoint = endpoint,
+        region = provider.region,
+        port = port,
+    })
+
+    local ai_module = require("apisix.plugins.ai." .. conf.llm_provider)
+    local create_request_text_segments = ai_module.create_request_text_segments
+
+    local text_segments = create_request_text_segments(msgs)
+    local res, err = comprehend:detectToxicContent({
+        LanguageCode = "en",
+        TextSegments = text_segments,
+    })
+
+    if not res then
+        core.log.error("failed to send request to ", provider, ": ", err)
+        return HTTP_INTERNAL_SERVER_ERROR, err
+    end
+
+    local results = res.body and res.body.ResultList
+    if type(results) ~= "table" or core.table.isempty(results) then
+        return HTTP_INTERNAL_SERVER_ERROR, "failed to get moderation results from response"
+    end
+
+    for _, result in ipairs(results) do
+        if conf.moderation_categories then
+            for _, item in pairs(result.Labels) do
+                if not conf.moderation_categories[item.Name] then
+                    goto continue
+                end
+                if item.Score > conf.moderation_categories[item.Name] then
+                    return HTTP_BAD_REQUEST, "request body exceeds " .. item.Name .. " threshold"
+                end
+                ::continue::
+            end
+        end
+
+        if result.Toxicity > conf.moderation_threshold then
+            return HTTP_BAD_REQUEST, "request body exceeds toxicity threshold"
+        end
+    end
+end
+
+return _M

apisix/plugins/ai/openai.lua

@@ -0,0 +1,33 @@
+--
+-- 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.
+--
+local core = require("apisix.core")
+local ipairs = ipairs
+
+local _M = {}
+
+
+function _M.create_request_text_segments(msgs)
+    local text_segments = {}
+    for _, msg in ipairs(msgs) do
+        core.table.insert_tail(text_segments, {
+            Text = msg.content
+        })
+    end
+    return text_segments
+end
+
+return  _M

conf/config.yaml.example

@@ -479,6 +479,7 @@ plugins:                           # plugin list (sorted by priority)
   - body-transformer               # priority: 1080
   - ai-prompt-template             # priority: 1071
   - ai-prompt-decorator            # priority: 1070
+  - ai-content-moderation          # priority: 1040 TODO: compare priority with other ai plugins
   - proxy-mirror                   # priority: 1010
   - proxy-rewrite                  # priority: 1008
   - workflow                       # priority: 1006

docs/en/latest/config.json

@@ -81,7 +81,8 @@
             "plugins/ext-plugin-post-req",
             "plugins/ext-plugin-post-resp",
             "plugins/inspect",
-            "plugins/ocsp-stapling"
+            "plugins/ocsp-stapling",
+            "plugins/ai-content-moderation"
           ]
         },
         {