20978: Merge branch 'main' into 20978-instance-types

[arvados.git] / services / api / config / initializers / reload_config.rb

diff --git a/services/api/config/initializers/reload_config.rb b/services/api/config/initializers/reload_config.rb
index 6a7eac7a539833d470ec16f1161a705a6969129b..22eee1601bb43940de5254c6cb10205181975d03 100644 (file)
--- a/services/api/config/initializers/reload_config.rb
+++ b/services/api/config/initializers/reload_config.rb
@@ -2,11 +2,10 @@
 #
 # SPDX-License-Identifier: AGPL-3.0
 
-if !File.owned?(Rails.root.join('tmp'))
-  Rails.logger.debug("reload_config: not owner of #{Rails.root}/tmp, skipping")
-elsif ENV["ARVADOS_CONFIG"] == "none"
-  Rails.logger.debug("reload_config: no config in use, skipping")
-else
+# When updating this, please make the same changes in
+# apps/workbench/config/initializers/reload_config.rb as well.
+
+def start_reload_thread
   Thread.new do
     lockfile = Rails.root.join('tmp', 'reload_config.lock')
     File.open(lockfile, File::WRONLY|File::CREAT, 0600) do |f|
@@ -16,16 +15,45 @@ else
       # which could be a long time.
       Rails.logger.debug("reload_config: waiting for lock on #{lockfile}")
       f.flock(File::LOCK_EX)
+
+      t_lastload = Rails.configuration.SourceTimestamp
+      hash_lastload = Rails.configuration.SourceSHA256
       conffile = ENV['ARVADOS_CONFIG'] || "/etc/arvados/config.yml"
-      Rails.logger.info("reload_config: polling for updated mtime on #{conffile} with threshold #{Rails.configuration.SourceTimestamp}")
+      Rails.logger.info("reload_config: polling for updated mtime on #{conffile} with threshold #{t_lastload}")
       while true
         sleep 1
         t = File.mtime(conffile)
-        if t.to_f > Rails.configuration.SourceTimestamp.to_f
+        # If the file is newer than 5s, re-read it even if the
+        # timestamp matches the previously loaded file. This enables
+        # us to detect changes even if the filesystem's timestamp
+        # precision cannot represent multiple updates per second.
+        if t.to_f != t_lastload.to_f || Time.now.to_f - t.to_f < 5
+          Open3.popen2("arvados-server", "config-dump", "-skip-legacy") do |stdin, stdout, status_thread|
+            confs = YAML.safe_load(stdout)
+            hash = confs["SourceSHA256"]
+          rescue => e
+            Rails.logger.info("reload_config: config file updated but could not be loaded: #{e}")
+            t_lastload = t
+            next
+          end
+          if hash == hash_lastload
+            # If we reloaded a new or updated file, but the content is
+            # identical, keep polling instead of restarting.
+            t_lastload = t
+            next
+          end
+
           restartfile = Rails.root.join('tmp', 'restart.txt')
           touchtime = Time.now
           Rails.logger.info("reload_config: mtime on #{conffile} changed to #{t}, touching #{restartfile} to #{touchtime}")
-          File.utime(touchtime, touchtime, restartfile)
+          begin
+            File.utime(touchtime, touchtime, restartfile)
+          rescue
+            # remove + re-create works even if the existing file is
+            # owned by root, provided the tempdir is writable.
+            File.unlink(restartfile) rescue nil
+            File.open(restartfile, 'w') {}
+          end
           # Even if passenger doesn't notice that we hit restart.txt
           # and kill our process, there's no point waiting around to
           # hit it again.
@@ -35,3 +63,15 @@ else
     end
   end
 end
+
+if !File.owned?(Rails.root.join('tmp'))
+  Rails.logger.debug("reload_config: not owner of #{Rails.root}/tmp, skipping")
+elsif ENV["ARVADOS_CONFIG"] == "none"
+  Rails.logger.debug("reload_config: no config in use, skipping")
+elsif defined?(PhusionPassenger)
+  PhusionPassenger.on_event(:starting_worker_process) do |forked|
+    start_reload_thread
+  end
+else
+  start_reload_thread
+end