refactor balancer into more testable and extensible interface
This commit is contained in:
Elvin Efendi
parent
1b5db4b3b0
commit
e9dc275b81
20 changed files with 368 additions and 467 deletions
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@ -1,269 +1,118 @@
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local cwd = io.popen("pwd"):read('*l')
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package.path = cwd .. "/rootfs/etc/nginx/lua/?.lua;" .. package.path
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package.path = "./rootfs/etc/nginx/lua/?.lua;./rootfs/etc/nginx/lua/test/mocks/?.lua;" .. package.path
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_G._TEST = true
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local balancer, mock_cjson, mock_config, mock_backends, mock_lrucache, lock, mock_lock,
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mock_ngx_balancer, mock_ewma
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local function dict_generator(vals)
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local _dict = { __index = {
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get = function(self, key)
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return self._vals[key]
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end,
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set = function(self, key, val)
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self._vals[key] = val
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return true, nil, false
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end,
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delete = function(self, key)
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return self:set(key, nil)
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end,
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flush_all = function(self)
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return
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end,
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_vals = vals
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}
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}
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return setmetatable({_vals = vals}, _dict)
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end
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local function backend_generator(name, endpoints, lb_alg)
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return {
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name = name,
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endpoints = endpoints,
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["load-balance"] = lb_alg,
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}
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end
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local default_endpoints = {
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{address = "000.000.000", port = "8080"},
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{address = "000.000.001", port = "8081"},
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local _ngx = {
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shared = {},
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log = function(...) end,
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}
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_G.ngx = _ngx
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local default_backends = {
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mock_rr_backend = backend_generator("mock_rr_backend", default_endpoints, "round_robin"),
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mock_ewma_backend = backend_generator("mock_ewma_backend", default_endpoints, "ewma"),
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}
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local balancer, expected_implementations, backends
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local function init()
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mock_cjson = {}
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mock_config = {}
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mock_ngx_balancer = {}
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mock_ewma = {
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sync = function(b) return end
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}
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mock_resty_balancer = {
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sync = function(b) return end,
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after_balance = function () return end
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}
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mock_backends = dict_generator(default_backends)
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mock_lrucache = {
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new = function () return mock_backends end
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}
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lock = {
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lock = function() return end,
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unlock = function() return end
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}
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mock_lock = {
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new = function () return lock end
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}
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_G.ngx = {
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shared = {
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balancer_ewma = dict_generator({}),
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balancer_ewma_last_touched_at = dict_generator({}),
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},
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var = {},
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log = function() return end,
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WARN = "warn",
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INFO = "info",
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ERR = "err",
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HTTP_SERVICE_UNAVAILABLE = 503,
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exit = function(status) return end,
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}
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package.loaded["ngx.balancer"] = mock_ngx_balancer
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package.loaded["resty.lrucache"] = mock_lrucache
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package.loaded["resty.string"] = {}
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package.loaded["resty.sha1"] = {}
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package.loaded["resty.md5"] = {}
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package.loaded["resty.cookie"] = {}
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package.loaded["cjson"] = mock_cjson
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package.loaded["resty.lock"] = mock_lock
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package.loaded["balancer.ewma"] = mock_ewma
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package.loaded["balancer.resty"] = mock_resty_balancer
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package.loaded["configuration"] = mock_config
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local function reset_balancer()
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package.loaded["balancer"] = nil
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balancer = require("balancer")
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end
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describe("[balancer_test]", function()
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setup(function()
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init()
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local function reset_expected_implementations()
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expected_implementations = {
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["access-router-production-web-80"] = package.loaded["balancer.round_robin"],
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["my-dummy-app-1"] = package.loaded["balancer.round_robin"],
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["my-dummy-app-2"] = package.loaded["balancer.chash"],
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["my-dummy-app-3"] = package.loaded["balancer.sticky"],
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["my-dummy-app-4"] = package.loaded["balancer.ewma"],
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["my-dummy-app-5"] = package.loaded["balancer.sticky"],
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}
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end
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local function reset_backends()
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backends = {
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{
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name = "access-router-production-web-80", port = "80", secure = false,
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secureCACert = { secret = "", caFilename = "", pemSha = "" },
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sslPassthrough = false,
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endpoints = {
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{ address = "10.184.7.40", port = "8080", maxFails = 0, failTimeout = 0 },
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{ address = "10.184.97.100", port = "8080", maxFails = 0, failTimeout = 0 },
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{ address = "10.184.98.239", port = "8080", maxFails = 0, failTimeout = 0 },
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},
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sessionAffinityConfig = { name = "", cookieSessionAffinity = { name = "", hash = "" } },
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},
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{ name = "my-dummy-app-1", ["load-balance"] = "round_robin", },
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{ name = "my-dummy-app-2", ["load-balance"] = "round_robin", ["upstream-hash-by"] = "$request_uri", },
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{
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name = "my-dummy-app-3", ["load-balance"] = "ewma",
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sessionAffinityConfig = { name = "cookie", cookieSessionAffinity = { name = "route", hash = "sha1" } }
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},
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{ name = "my-dummy-app-4", ["load-balance"] = "ewma", },
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{
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name = "my-dummy-app-5", ["load-balance"] = "ewma", ["upstream-hash-by"] = "$request_uri",
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sessionAffinityConfig = { name = "cookie", cookieSessionAffinity = { name = "route", hash = "sha1" } }
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},
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}
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end
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describe("Balancer", function()
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before_each(function()
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reset_balancer()
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reset_expected_implementations()
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reset_backends()
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end)
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teardown(function()
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local packages = {"ngx.balancer", "resty.lrucache","cjson", "resty.lock", "balancer.ewma","configuration"}
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for i, package_name in ipairs(packages) do
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package.loaded[package_name] = nil
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end
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end)
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describe("balancer.call():", function()
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setup(function()
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mock_ngx_balancer.set_more_tries = function () return end
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mock_ngx_balancer.set_current_peer = function () return end
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mock_ewma.after_balance = function () return end
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describe("get_implementation()", function()
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it("returns correct implementation for given backend", function()
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for _, backend in pairs(backends) do
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local expected_implementation = expected_implementations[backend.name]
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local implementation = balancer.get_implementation(backend)
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assert.equal(expected_implementation, balancer.get_implementation(backend))
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end
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end)
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end)
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describe("sync_backend()", function()
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local backend, implementation
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before_each(function()
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_G.ngx.get_phase = nil
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_G.ngx.var = {}
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mock_backends._vals = default_backends
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backend = backends[1]
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implementation = expected_implementations[backend.name]
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end)
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describe("phase=log", function()
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before_each(function()
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_G.ngx.get_phase = function() return "log" end
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end)
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it("initializes balancer for given backend", function()
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local s = spy.on(implementation, "new")
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it("lb_alg=ewma, ewma_after_balance was called", function()
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_G.ngx.var.proxy_upstream_name = "mock_ewma_backend"
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local ewma_after_balance_spy = spy.on(mock_ewma, "after_balance")
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mock_resty_balancer.is_applicable = function(b) return false end
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assert.has_no_errors(balancer.call)
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assert.spy(ewma_after_balance_spy).was_called()
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end)
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it("lb_alg=round_robin, ewma_after_balance was not called", function()
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_G.ngx.var.proxy_upstream_name = "mock_rr_backend"
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local ewma_after_balance_spy = spy.on(mock_ewma, "after_balance")
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mock_resty_balancer.is_applicable = function(b) return true end
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assert.has_no_errors(balancer.call)
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assert.spy(ewma_after_balance_spy).was_not_called()
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end)
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assert.has_no.errors(function() balancer.sync_backend(backend) end)
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assert.spy(s).was_called_with(implementation, backend)
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end)
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describe("phase=balancer", function()
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before_each(function()
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_G.ngx.get_phase = function() return "balancer" end
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end)
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it("replaces the existing balancer when load balancing config changes for backend", function()
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assert.has_no.errors(function() balancer.sync_backend(backend) end)
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it("lb_alg=round_robin, peer was successfully set", function()
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_G.ngx.var.proxy_upstream_name = "mock_rr_backend"
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backend["load-balance"] = "ewma"
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local new_implementation = package.loaded["balancer.ewma"]
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local backend_get_spy = spy.on(mock_backends, "get")
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local set_more_tries_spy = spy.on(mock_ngx_balancer, "set_more_tries")
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local set_current_peer_spy = spy.on(mock_ngx_balancer, "set_current_peer")
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local s_old = spy.on(implementation, "new")
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local s = spy.on(new_implementation, "new")
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local s_ngx_log = spy.on(_G.ngx, "log")
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mock_resty_balancer.balance = function(b) return {address = "000.000.000", port = "8080"} end
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assert.has_no_errors(balancer.call)
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assert.spy(backend_get_spy).was_called_with(match.is_table(), "mock_rr_backend")
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assert.spy(set_more_tries_spy).was_called_with(1)
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assert.spy(set_current_peer_spy).was_called_with("000.000.000", "8080")
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mock_backends.get:clear()
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mock_ngx_balancer.set_more_tries:clear()
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mock_ngx_balancer.set_current_peer:clear()
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mock_resty_balancer.balance = function(b) return {address = "000.000.001", port = "8081"} end
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assert.has_no_errors(balancer.call)
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assert.spy(backend_get_spy).was_called_with(match.is_table(), "mock_rr_backend")
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assert.spy(set_more_tries_spy).was_called_with(1)
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assert.spy(set_current_peer_spy).was_called_with("000.000.001", "8081")
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end)
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it("lb_alg=ewma, peer was successfully set", function()
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_G.ngx.var.proxy_upstream_name = "mock_ewma_backend"
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mock_ewma.balance = function(b) return {address = "000.000.111", port = "8083"} end
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local backend_get_spy = spy.on(mock_backends, "get")
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local set_more_tries_spy = spy.on(mock_ngx_balancer, "set_more_tries")
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local set_current_peer_spy = spy.on(mock_ngx_balancer, "set_current_peer")
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mock_resty_balancer.is_applicable = function(b) return false end
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assert.has_no_errors(balancer.call)
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assert.spy(backend_get_spy).was_called_with(match.is_table(), "mock_ewma_backend")
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assert.spy(set_more_tries_spy).was_called_with(1)
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assert.spy(set_current_peer_spy).was_called_with("000.000.111", "8083")
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end)
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it("fails when no backend exists", function()
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_G.ngx.var.proxy_upstream_name = "mock_rr_backend"
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mock_backends._vals = {}
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local backend_get_spy = spy.on(mock_backends, "get")
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local set_current_peer_spy = spy.on(mock_ngx_balancer, "set_current_peer")
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assert.has_no_errors(balancer.call)
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assert.are_equal(ngx.status, 503)
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assert.spy(backend_get_spy).was_called_with(match.is_table(), "mock_rr_backend")
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assert.spy(set_current_peer_spy).was_not_called()
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end)
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assert.has_no.errors(function() balancer.sync_backend(backend) end)
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assert.spy(s_ngx_log).was_called_with(ngx.ERR,
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"LB algorithm changed from round_robin to ewma, resetting the instance")
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-- TODO(elvinefendi) figure out why
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-- assert.spy(s).was_called_with(new_implementation, backend) does not work here
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assert.spy(s).was_called(1)
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assert.spy(s_old).was_not_called()
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end)
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describe("not in phase log or balancer", function()
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it("returns errors", function()
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_G.ngx.get_phase = function() return "nope" end
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assert.has_error(balancer.call, "must be called in balancer or log, but was called in: nope")
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end)
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end)
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end)
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it("calls sync(backend) on existing balancer instance when load balancing config does not change", function()
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local mock_instance = { sync = function(...) end }
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setmetatable(mock_instance, implementation)
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implementation.new = function(self, backend) return mock_instance end
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assert.has_no.errors(function() balancer.sync_backend(backend) end)
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describe("balancer.init_worker():", function()
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setup(function()
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_G.ngx.timer = {
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every = function(interval, func) return func() end
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}
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mock_cjson.decode = function(x) return x end
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end)
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stub(mock_instance, "sync")
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before_each(function()
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mock_backends._vals = default_backends
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end)
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describe("sync_backends():", function()
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it("succeeds when no sync is required", function()
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mock_config.get_backends_data = function() return default_backends end
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local backend_set_spy = spy.on(mock_backends, "set")
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assert.has_no_errors(balancer.init_worker)
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assert.spy(backend_set_spy).was_not_called()
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end)
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it("lb_alg=round_robin, updates backend when sync is required", function()
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mock_config.get_backends_data = function() return { default_backends.mock_rr_backend } end
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mock_backends._vals = {}
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local backend_set_spy = spy.on(mock_backends, "set")
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local ewma_flush_spy = spy.on(_G.ngx.shared.balancer_ewma, "flush_all")
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local ewma_lta_flush_spy = spy.on(_G.ngx.shared.balancer_ewma_last_touched_at, "flush_all")
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mock_resty_balancer.balance = function(b) return {address = "000.000.000", port = "8080"} end
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mock_resty_balancer.reinit = function(b) return end
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assert.has_no_errors(balancer.init_worker)
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assert.spy(backend_set_spy)
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.was_called_with(match.is_table(), default_backends.mock_rr_backend.name, match.is_table())
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assert.spy(ewma_flush_spy).was_not_called()
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assert.spy(ewma_lta_flush_spy).was_not_called()
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end)
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it("lb_alg=ewma, updates backend when sync is required", function()
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_G.ngx.var.proxy_upstream_name = "mock_ewma_backend"
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mock_config.get_backends_data = function() return { default_backends.mock_ewma_backend } end
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mock_backends._vals = {}
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local backend_set_spy = spy.on(mock_backends, "set")
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local ewma_sync_spy = spy.on(mock_ewma, "sync")
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mock_resty_balancer.is_applicable = function(b) return false end
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assert.has_no_errors(balancer.init_worker)
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assert.spy(backend_set_spy)
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.was_called_with(match.is_table(), default_backends.mock_ewma_backend.name, match.is_table())
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assert.spy(ewma_sync_spy).was_called()
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end)
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assert.has_no.errors(function() balancer.sync_backend(backend) end)
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assert.stub(mock_instance.sync).was_called_with(mock_instance, backend)
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end)
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end)
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end)
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