wehub-resource-sync
150 lines
4.0 KiB
Lua
150 lines
4.0 KiB
Lua
--- Contextual data for the current request.
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--
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-- @module kong.ctx
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local get_request = require("resty.core.base").get_request
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local setmetatable = setmetatable
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local ngx = ngx
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-- shared between all global instances
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local _CTX_SHARED_KEY = {}
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local _CTX_CORE_KEY = {}
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---
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-- A table that has the same lifetime as the current request. This table is shared
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-- between all plugins. It can be used to share data between several plugins in a
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-- given request.
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--
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-- This table is only relevant in the context of a request and cannot be
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-- accessed from the top-level chunk of Lua modules. Instead, it can only be
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-- accessed in request phases, which are represented by the `rewrite`,
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-- `access`, `header_filter`, `response`, `body_filter`, `log`, and `preread` phases of
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-- the plugin interfaces. Accessing this table in those functions (and their
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-- callees) is fine.
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--
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-- Values inserted in this table by a plugin are visible by all other
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-- plugins. Be careful when interacting with values in this table, as a naming
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-- conflict could result in the overwrite of data.
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--
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-- @table kong.ctx.shared
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-- @phases rewrite, access, header_filter, response, body_filter, log, preread
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-- @usage
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-- -- Two plugins A and B, and if plugin A has a higher priority than B's
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-- -- (it executes before B):
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--
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-- -- plugin A handler.lua
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-- function plugin_a_handler:access(conf)
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-- kong.ctx.shared.foo = "hello world"
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--
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-- kong.ctx.shared.tab = {
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-- bar = "baz"
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-- }
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-- end
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--
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-- -- plugin B handler.lua
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-- function plugin_b_handler:access(conf)
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-- kong.log(kong.ctx.shared.foo) -- "hello world"
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-- kong.log(kong.ctx.shared.tab.bar) -- "baz"
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-- end
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---
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-- A table that has the same lifetime as the current request. Unlike
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-- `kong.ctx.shared`, this table is **not** shared between plugins.
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-- Instead, it is only visible for the current plugin instance.
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-- For example, if several instances of the Rate Limiting plugin
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-- are configured on different Services, each instance has its
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-- own table for every request.
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--
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-- Because of its namespaced nature, this table is safer for a plugin to use
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-- than `kong.ctx.shared` since it avoids potential naming conflicts, which
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-- could lead to several plugins unknowingly overwriting each other's data.
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--
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-- This table is only relevant in the context of a request and cannot be
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-- accessed from the top-level chunk of Lua modules. Instead, it can only be
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-- accessed in request phases, which are represented by the `rewrite`,
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-- `access`, `header_filter`, `body_filter`, `log`, and `preread` phases
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-- of the plugin interfaces. Accessing this table in those functions (and
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-- their callees) is fine.
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--
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-- Values inserted in this table by a plugin are visible in successful
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-- phases of this plugin's instance only.
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--
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-- @table kong.ctx.plugin
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-- @phases rewrite, access, header_filter, response, body_filter, log, preread
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-- @usage
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-- -- plugin handler.lua
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--
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-- -- For example, if a plugin wants to
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-- -- save some value for post-processing during the `log` phase:
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--
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-- function plugin_handler:access(conf)
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-- kong.ctx.plugin.val_1 = "hello"
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-- kong.ctx.plugin.val_2 = "world"
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-- end
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--
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-- function plugin_handler:log(conf)
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-- local value = kong.ctx.plugin.val_1 .. " " .. kong.ctx.plugin.val_2
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--
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-- kong.log(value) -- "hello world"
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-- end
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local function get_namespace(ctx, k)
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if not ctx then
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ctx = ngx.ctx
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end
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local namespaces = ctx.KONG_NAMESPACES
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if not namespaces then
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return
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end
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return namespaces[k]
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end
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local function new()
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local _CTX = {}
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local _ctx_mt = {}
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function _ctx_mt.__index(_, k)
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if not get_request() then
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return
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end
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local nctx = ngx.ctx
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local key
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if k == "core" then
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key = _CTX_CORE_KEY
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elseif k == "shared" then
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key = _CTX_SHARED_KEY
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else
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key = get_namespace(nctx, k)
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end
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if key then
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local ctx = nctx[key]
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if not ctx then
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ctx = {}
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nctx[key] = ctx
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end
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return ctx
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end
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end
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return setmetatable(_CTX, _ctx_mt)
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end
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return {
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new = new,
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}
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