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