Merge pull request #715 from NatLabRockies/brownouts

Add feature for scheduled API brownouts

Author: GUI

config/schema.cue

@@ -565,6 +565,19 @@ import "path"
     ssl_cert?: string
     ssl_cert_key?: string
     rewrites?: [...string]
+
+    #scheduled_brownout: {
+      path_regex: string
+      message?: string
+      status_code?: uint
+
+      #schedule: {
+        start_time: string
+        end_time: string
+      }
+      schedule: [...#schedule]
+    }
+    scheduled_brownouts?: [...#scheduled_brownout]
   }
   hosts: [...#host] | *[]
 
@@ -691,6 +704,11 @@ import "path"
         code: "HTTPS_REQUIRED"
         message: "Requests must be made over HTTPS. Try accessing the API at: {{https_url}}"
       }
+      scheduled_brownout: {
+        status_code: 410
+        code: "SCHEDULED_BROWNOUT"
+        message: "This API will be going away. Seek an alternative API. Contact us at {{contact_url}} for assistance."
+      }
     }
   }
   default_api_backend_settings: #api_backend_settings | *_default_api_backend_settings_value
@@ -743,6 +761,7 @@ import "path"
       over_rate_limit?: {...}
       internal_server_error?: {...}
       https_required?: {...}
+      scheduled_brownout?: {...}
     }
   }
   #api_backend_sub_settings: {

src/api-umbrella/proxy/error_handler.lua

@@ -167,6 +167,10 @@ return function(ngx_ctx, denied_code, settings, extra_data)
   -- also allowed via CORS).
   ngx_header["Access-Control-Allow-Origin"] = "*"
 
+  if error_data["cache_control"] then
+    ngx_header["Cache-Control"] = error_data["cache_control"]
+  end
+
   ngx.status = status_code
   ngx_header.content_type = content_type
   ngx_print(output)

src/api-umbrella/proxy/hooks/access.lua

@@ -17,6 +17,7 @@ local referer_validator = require "api-umbrella.proxy.middleware.referer_validat
 local resolve_api_key = require "api-umbrella.proxy.middleware.resolve_api_key"
 local rewrite_request = require "api-umbrella.proxy.middleware.rewrite_request"
 local role_validator = require "api-umbrella.proxy.middleware.role_validator"
+local scheduled_brownout = require "api-umbrella.proxy.middleware.scheduled_brownout"
 local user_settings = require "api-umbrella.proxy.middleware.user_settings"
 
 local err
@@ -30,6 +31,11 @@ if err then
   return error_handler(ngx_ctx, err, settings)
 end
 
+err, err_data = scheduled_brownout(ngx_ctx, api)
+if err then
+  return error_handler(ngx_ctx, err, settings, err_data)
+end
+
 -- Find the API key set on the request.
 err = resolve_api_key(ngx_ctx)
 if err then

src/api-umbrella/proxy/hooks/init_preload_modules.lua

@@ -20,6 +20,7 @@ require "api-umbrella.proxy.middleware.resolve_api_key"
 require "api-umbrella.proxy.middleware.rewrite_request"
 require "api-umbrella.proxy.middleware.rewrite_response"
 require "api-umbrella.proxy.middleware.role_validator"
+require "api-umbrella.proxy.middleware.scheduled_brownout"
 require "api-umbrella.proxy.middleware.user_settings"
 require "api-umbrella.proxy.middleware.website_matcher"
 require "api-umbrella.proxy.opensearch_templates_data"

src/api-umbrella/proxy/middleware/api_matcher.lua

@@ -14,10 +14,11 @@ local function apis_for_request_host(ngx_ctx, active_config)
 
   local all_apis = active_config["api_backends"] or {}
   local apis_for_default_host = {}
+  local host_normalized = ngx_ctx.host_normalized
   for _, api in ipairs(all_apis) do
-    if matches_hostname(ngx_ctx, api["_frontend_host_normalized"], api["_frontend_host_wildcard_regex"]) then
+    if matches_hostname(host_normalized, api["_frontend_host_normalized"], api["_frontend_host_wildcard_regex"]) then
       table.insert(apis, api)
-    elseif api["_frontend_host_normalized"] == config["_default_hostname_normalized"]then
+    elseif api["_frontend_host_normalized"] == config["_default_hostname_normalized"] then
       table.insert(apis_for_default_host, api)
     end
   end

src/api-umbrella/proxy/middleware/scheduled_brownout.lua

@@ -0,0 +1,38 @@
+local config = require("api-umbrella.utils.load_config")()
+
+local ngx_var = ngx.var
+local now = ngx.now
+local re_find = ngx.re.find
+
+return function(ngx_ctx, api)
+  local scheduled_brownouts = api["_scheduled_brownouts"]
+  if scheduled_brownouts then
+    local current_time = now()
+    if config["app_env"] == "test" then
+      local fake_time = ngx_var.http_x_fake_time
+      if fake_time then
+        current_time = tonumber(fake_time)
+      end
+    end
+
+    local original_uri_path = ngx_ctx.original_uri_path
+    for _, scheduled_brownout in ipairs(scheduled_brownouts) do
+      for _, schedule in ipairs(scheduled_brownout["schedule"]) do
+        if current_time >= schedule["_start_time_timestamp"] and current_time < schedule["_end_time_timestamp"] then
+          local find_from, _, find_err = re_find(original_uri_path, scheduled_brownout["path_regex"], "jo")
+          if find_from then
+            return "scheduled_brownout", {
+              status_code = scheduled_brownout["status_code"],
+              message = scheduled_brownout["message"],
+              cache_control = "no-store",
+            }
+          elseif find_err then
+            ngx.log(ngx.ERR, "regex error: ", find_err)
+          end
+        end
+      end
+    end
+  end
+
+  return nil
+end

src/api-umbrella/proxy/middleware/website_matcher.lua

@@ -4,10 +4,11 @@ local matches_hostname = require "api-umbrella.utils.matches_hostname"
 return function(ngx_ctx, active_config)
   local websites = active_config["website_backends"] or {}
   local default_website
+  local host_normalized = ngx_ctx.host_normalized
   for _, website in ipairs(websites) do
-    if matches_hostname(ngx_ctx, website["_frontend_host_normalized"], website["_frontend_host_wildcard_regex"]) then
+    if matches_hostname(host_normalized, website["_frontend_host_normalized"], website["_frontend_host_wildcard_regex"]) then
       return website
-    elseif website["_frontend_host_normalized"] == config["_default_hostname_normalized"]then
+    elseif website["_frontend_host_normalized"] == config["_default_hostname_normalized"] then
       default_website = website
     end
   end

src/api-umbrella/utils/active_config_store/cache_computed_api_backend.lua

@@ -1,5 +1,7 @@
+local append_array = require "api-umbrella.utils.append_array"
 local escape_regex = require "api-umbrella.utils.escape_regex"
 local host_normalize = require "api-umbrella.utils.host_normalize"
+local matches_hostname = require "api-umbrella.utils.matches_hostname"
 local mustache_unescape = require "api-umbrella.utils.mustache_unescape"
 local set_hostname_regex = require "api-umbrella.utils.active_config_store.set_hostname_regex"
 local split = require("pl.utils").split
@@ -9,7 +11,24 @@ local table_size = require("pl.tablex").size
 local decode_args = ngx.decode_args
 local re_gsub = ngx.re.gsub
 
-return function(api)
+local function cache_scheduled_brownouts(config, api)
+  local hosts = config["hosts"]
+  if hosts then
+    local frontend_host_normalized = api["_frontend_host_normalized"]
+    for _, host in ipairs(hosts) do
+      local scheduled_brownouts = host["scheduled_brownouts"]
+      if scheduled_brownouts and (frontend_host_normalized == host["_hostname_normalized"] or matches_hostname(frontend_host_normalized, host["_hostname_normalized"], host["_hostname_wildcard_regex"])) then
+        if api["_scheduled_brownouts"] == nil then
+          api["_scheduled_brownouts"] = {}
+        end
+
+        append_array(api["_scheduled_brownouts"], scheduled_brownouts)
+      end
+    end
+  end
+end
+
+return function(config, api)
   if not api then return end
 
   if api["frontend_host"] then
@@ -118,4 +137,6 @@ return function(api)
       end
     end
   end
+
+  cache_scheduled_brownouts(config, api)
 end

src/api-umbrella/utils/active_config_store/parse_api_backends.lua

@@ -12,7 +12,7 @@ local function parse_api(api)
     api["id"] = stable_object_hash(api)
   end
 
-  cache_computed_api_backend(api)
+  cache_computed_api_backend(config, api)
   cache_computed_api_backend_sub_settings(config, api["sub_settings"], deep_merge_overwrite_arrays(deepcopy(config["default_api_backend_settings"]), api["settings"]))
   cache_computed_api_backend_settings(config, api["settings"], config["default_api_backend_settings"])
 end

src/api-umbrella/utils/generate_runtime_config.lua

@@ -11,6 +11,7 @@ local host_normalize = require "api-umbrella.utils.host_normalize"
 local invert_table = require "api-umbrella.utils.invert_table"
 local is_empty = require "api-umbrella.utils.is_empty"
 local isfile = require("pl.path").isfile
+local iso8601_to_timestamp = require("api-umbrella.utils.time").iso8601_to_timestamp
 local json_decode = require("cjson").decode
 local json_encode = require "api-umbrella.utils.json_encode"
 local mkdir_p = require "api-umbrella.utils.mkdir_p"
@@ -19,6 +20,7 @@ local path_exists = require "api-umbrella.utils.path_exists"
 local path_join = require "api-umbrella.utils.path_join"
 local pl_utils = require "pl.utils"
 local random_token = require "api-umbrella.utils.random_token"
+local set_hostname_regex = require "api-umbrella.utils.active_config_store.set_hostname_regex"
 local shell_blocking_capture = require("shell-games").capture
 local stat = require "posix.sys.stat"
 local strip = require("pl.stringx").strip
@@ -179,6 +181,8 @@ local function set_computed_config(config)
 
   local default_host_exists = false
   for _, host in ipairs(config["hosts"]) do
+    set_hostname_regex(host, "hostname")
+
     if host["default"] then
       default_host_exists = true
     end
@@ -188,6 +192,15 @@ local function set_computed_config(config)
     else
       host["_nginx_server_name"] = host["hostname"]
     end
+
+    if host["scheduled_brownouts"] then
+      for _, scheduled_brownout in ipairs(host["scheduled_brownouts"]) do
+        for _, schedule in ipairs(scheduled_brownout["schedule"]) do
+          schedule["_start_time_timestamp"] = iso8601_to_timestamp(schedule["start_time"])
+          schedule["_end_time_timestamp"] = iso8601_to_timestamp(schedule["end_time"])
+        end
+      end
+    end
   end
 
   -- If a default host hasn't been explicitly defined, then add a default