Fix Lapis initialization not taking place during ngx.timer.at callbacks

Exposed by running `bundle exec minitest test/apis/v0/test_analytics.rb
-n test_expected_response` by itself, the basic issue is that the
database initialization needs to happen for async nginx timers, since
otherwise it only happens in the pre-request callback.

This cropped up after the Lapis 1.7 upgrade and the changes in 7562163.
But it seems like it was related to the 1.7 upgrade, since even without
the new database init approach, this problem would occur. But I think
this new approach actually makes more sense, because it seems logical
that the async callbacks would also need something to setup their
database pool connections.

Author: GUI

src/api-umbrella/web-app/actions/v0/analytics.lua

@@ -14,6 +14,7 @@ local respond_to = require "api-umbrella.web-app.utils.respond_to"
 local stable_object_hash = require "api-umbrella.utils.stable_object_hash"
 local t = require("api-umbrella.web-app.utils.gettext").gettext
 local time = require "api-umbrella.utils.time"
+local timer_at = require "api-umbrella.web-app.utils.timer_at"
 
 local db_statement_timeout_ms = config["web"]["analytics_v0_summary_db_timeout"] * 1000
 
@@ -325,7 +326,7 @@ function _M.summary(self)
     -- users don't get a super slow response and we don't overwhelm the server
     -- when it's uncached).
     if cache:updated_at_timestamp() < ngx.now() - 60 * 60 * 6 then
-      ngx.timer.at(0, function()
+      timer_at(0, function()
         -- Ensure only one pre-seed is happening at a time (at least per
         -- server).
         interval_lock.mutex_exec("preseed_analytics_summary_cache", generate_summary)
@@ -337,7 +338,7 @@ function _M.summary(self)
 
     -- Trigger analytics generation in background so if it takes longer than
     -- this request, it can still populate.
-    ngx.timer.at(0, function()
+    timer_at(0, function()
       -- Ensure only one pre-seed is happening at a time (at least per
       -- server).
       interval_lock.mutex_exec("initial_analytics_summary_cache", generate_summary)

src/api-umbrella/web-app/app.lua

@@ -1,7 +1,7 @@
 local Admin = require "api-umbrella.web-app.models.admin"
 local config = require("api-umbrella.utils.load_config")()
 local csrf = require "api-umbrella.web-app.utils.csrf"
-local db = require "lapis.db"
+local db_init = require "api-umbrella.web-app.utils.db_init"
 local error_messages_by_field = require "api-umbrella.web-app.utils.error_messages_by_field"
 local escape_html = require("lapis.html").escape
 local flash = require "api-umbrella.web-app.utils.flash"
@@ -10,7 +10,6 @@ local http_headers = require "api-umbrella.utils.http_headers"
 local is_empty = require "api-umbrella.utils.is_empty"
 local lapis = require "lapis"
 local lapis_config = require("lapis.config").get()
-local pg_utils = require "api-umbrella.utils.pg_utils"
 local refresh_local_active_config_cache = require("api-umbrella.web-app.stores.active_config_store").refresh_local_cache
 local resty_session = require "resty.session"
 local t = require("api-umbrella.web-app.utils.gettext").gettext
@@ -160,20 +159,7 @@ local function current_admin_from_session(self)
 end
 
 local function before_filter(self)
-  -- Set session variables for the database connection (always use UTC and set
-  -- an app name for auditing).
-  local pg = db.connect()
-  -- I don't think this should really be possible, but if somehow lapis has
-  -- already established a connection, then `db.connect()` will return `nil`.
-  -- So in that case, fetch the cached connection Lapis uses internally, and
-  -- force the full setup (even if it's a reused socket), since we don't know
-  -- if this socket was fully setup by Lapis or not.
-  local force_first_time_setup = false
-  if not pg then
-    pg = ngx.ctx.pgmoon_default
-    force_first_time_setup = true
-  end
-  pg_utils.setup_connection(pg, "api-umbrella-web-app", force_first_time_setup)
+  db_init()
 
   -- Refresh cache per request if background polling is disabled.
   if config["router"]["active_config"]["refresh_local_cache_interval"] == 0 then

src/api-umbrella/web-app/hooks/init_preload_modules.lua

@@ -119,6 +119,7 @@ require "api-umbrella.web-app.utils.csrf"
 require "api-umbrella.web-app.utils.csv"
 require "api-umbrella.web-app.utils.datatables"
 require "api-umbrella.web-app.utils.db_escape_patches"
+require "api-umbrella.web-app.utils.db_init"
 require "api-umbrella.web-app.utils.dbify_json_nulls"
 require "api-umbrella.web-app.utils.error_messages_by_field"
 require "api-umbrella.web-app.utils.flash"
@@ -136,6 +137,7 @@ require "api-umbrella.web-app.utils.pretty_yaml_dump"
 require "api-umbrella.web-app.utils.require_admin"
 require "api-umbrella.web-app.utils.respond_to"
 require "api-umbrella.web-app.utils.test_env_mock_userinfo"
+require "api-umbrella.web-app.utils.timer_at"
 require "api-umbrella.web-app.utils.username_label"
 require "api-umbrella.web-app.utils.validation_ext"
 require "api-umbrella.web-app.utils.wrapped_json_params"
@@ -163,6 +165,7 @@ require "lapis.db.model"
 require "lapis.db.model.relations"
 require "lapis.features.etlua"
 require "lapis.html"
+require "lapis.nginx"
 require "lapis.util"
 require "libcidr-ffi"
 require "lualdap"

src/api-umbrella/web-app/utils/db_init.lua

@@ -0,0 +1,23 @@
+local db = require "lapis.db"
+local pg_utils = require "api-umbrella.utils.pg_utils"
+
+-- Set session variables for the database connection that Lapis uses (always
+-- use UTC and set an app name for auditing). This needs to be called before
+-- Lapis `db.query` is called (by either Lapis requests, or also before Lapis
+-- timers).
+return function()
+  local pg = db.connect()
+
+  -- I don't think this should really be possible, but if somehow lapis has
+  -- already established a connection, then `db.connect()` will return `nil`.
+  -- So in that case, fetch the cached connection Lapis uses internally, and
+  -- force the full setup (even if it's a reused socket), since we don't know
+  -- if this socket was fully setup by Lapis or not.
+  local force_first_time_setup = true
+  if not pg then
+    pg = ngx.ctx.pgmoon_default
+    force_first_time_setup = true
+  end
+
+  pg_utils.setup_connection(pg, "api-umbrella-web-app", force_first_time_setup)
+end

src/api-umbrella/web-app/utils/timer_at.lua

@@ -0,0 +1,16 @@
+local db_init = require "api-umbrella.web-app.utils.db_init"
+local timer_at = require("lapis.nginx").timer_at
+
+-- For Lapis web app requests instead of using `ngx.timer.at`, use this wrapper which accomplishes 2 things:
+--
+-- 1. Uses Lapis' existing wrapper to ensure db disconnect or other after tasks
+--    occur:
+--    https://github.com/leafo/lapis/blob/v1.17.0/lapis/nginx.moon#L166-L177
+-- 2. Integrate our own `db_init` handler to ensure database connections inside
+--    the timer have the proper search_path and other settings configured.
+return function(delay, callback, ...)
+  timer_at(delay, function(_premature, ...)
+    db_init()
+    return callback(...)
+  end, ...)
+end