feat: add workflow plugin(mvp)

apisix/plugins/workflow.lua

@@ -0,0 +1,132 @@
+--
+-- 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 expr       = require("resty.expr.v1")
+local ipairs     = ipairs
+local tonumber   = tonumber
+
+local schema = {
+    type = "object",
+    properties = {
+        rules = {
+            type = "array",
+            items = {
+                type = "object",
+                properties = {
+                    case = {
+                        type = "array",
+                        items = {
+                            type = "array",
+                        },
+                        minItems = 1,
+                    },
+                    actions = {
+                        type = "array",
+                        items = {
+                            type = "array",
+                            minItems = 1
+                        }
+                    }
+                },
+                required = {"case", "actions"}
+            }
+        }
+    }
+}
+
+local plugin_name = "workflow"
+
+local _M = {
+    version = 0.1,
+    priority = 1006,
+    name = plugin_name,
+    schema = schema
+}
+
+
+local return_schema = {
+    type = "object",
+    properties = {
+        code = {
+            type = "integer",
+            minimum = 100,
+            maximum = 599
+        }
+    },
+    required = {"code"}
+}
+
+
+local function exit(conf)
+    local code = tonumber(conf.code)
+    return code, {error_msg = "rejected by workflow"}
+end
+
+
+local support_action = {
+    ["return"] = {
+        handler  = exit,
+        schema   = return_schema,
+    },
+}
+
+
+function _M.check_schema(conf)
+    local ok, err = core.schema.check(schema, conf)
+    if not ok then
+        return false, err
+    end
+
+    for _, rule in ipairs(conf.rules) do
+        local ok, err = expr.new(rule.case)
+        if not ok then
+            return false, "failed to validate the 'case' expression: " .. err
+        end
+
+        local actions = rule.actions
+        for _, action in ipairs(actions) do
+
+            if not support_action[action[1]] then
+                return false, "unsupported action: " .. action[1]
+            end
+
+            local ok, err = core.schema.check(support_action[action[1]].schema, action[2])
+            if not ok then
+                return false, "failed to validate the '" .. action[1] .. "' action: " .. err
+            end
+       end
+    end
+
+    return true
+end
+
+
+function _M.access(conf, ctx)
+    local match_result
+    for _, rule in ipairs(conf.rules) do
+        local expr, _ = expr.new(rule.case)
+        match_result = expr:eval(ctx.var)
+        if match_result then
+            -- only one action is currently supported
+            local action = rule.actions[1]
+            return support_action[action[1]].handler(action[2])
+        end
+    end
+end
+
+
+return _M

conf/config-default.yaml

@@ -430,6 +430,7 @@ plugins:                          # plugin list (sorted by priority)
   - proxy-mirror                   # priority: 1010
   - proxy-cache                    # priority: 1009
   - proxy-rewrite                  # priority: 1008
+  - workflow                       # priority: 1006
   - api-breaker                    # priority: 1005
   - limit-conn                     # priority: 1003
   - limit-count                    # priority: 1002

t/admin/plugins.t

@@ -93,6 +93,7 @@ authz-keycloak
 proxy-mirror
 proxy-cache
 proxy-rewrite
+workflow
 api-breaker
 limit-conn
 limit-count