feat: recover on pg_terminate_backend

CHANGELOG.md

@@ -14,6 +14,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
  - #2703, Add pre-config function - @steve-chavez
  + New config option `db-pre-config`(empty by default)
  + Allows using the in-database configuration without SUPERUSER
+ - #2781, Start automatic connection recovery when pool connections are closed with pg_terminate_backend - @steve-chavez
 
 ### Fixed
 

src/PostgREST/AppState.hs

@@ -24,8 +24,7 @@ module PostgREST.AppState
  , runListener
  ) where
 
-import qualified Data.ByteString as BS
-import qualified Data.ByteString.Char8 as BS8
+import qualified Data.ByteString.Char8 as BS
 import qualified Data.ByteString.Lazy as LBS
 import Data.Either.Combinators (whenLeft)
 import qualified Data.Text.Encoding as T
@@ -456,7 +455,7 @@ checkIsFatal (SQL.ConnectionUsageError e)
  where isAuthFailureMessage =
  ("FATAL: password authentication failed" `isInfixOf` failureMessage) ||
  ("no password supplied" `isInfixOf` failureMessage)
- failureMessage = BS8.unpack $ fromMaybe mempty e
+ failureMessage = BS.unpack $ fromMaybe mempty e
 checkIsFatal(SQL.SessionUsageError (SQL.QueryError _ _ (SQL.ResultError serverError)))
  = case serverError of
  -- Check for a syntax error (42601 is the pg code). This would mean the error is on our part somehow, so we treat it as fatal.

src/PostgREST/Error.hs

@@ -428,6 +428,7 @@ pgErrorStatus authed (SQL.SessionUsageError (SQL.QueryError _ _ (SQL.ResultError
  '5':'3':_ -> HTTP.status503 -- insufficient resources
  '5':'4':_ -> HTTP.status413 -- too complex
  '5':'5':_ -> HTTP.status500 -- obj not on prereq state
+ '5':'7':'P':'0':'1':_ -> HTTP.status503 -- terminating connection due to administrator command
  '5':'7':_ -> HTTP.status500 -- operator intervention
  '5':'8':_ -> HTTP.status500 -- system error
  'F':'0':_ -> HTTP.status500 -- conf file error