From 4064a7b984ca52402a76bb0b7e2ffb3018396638 Mon Sep 17 00:00:00 2001
From: SteveBash <ioexception02@gmail.com>
Date: Sat, 29 Oct 2016 13:38:19 -0500
Subject: [PATCH] Fix fatal error on postgres unsupported version, also fix
 #577 format of supported version

---
 CHANGELOG.md            |  1 +
 main/Main.hs            |  9 +++++----
 src/PostgREST/Config.hs | 11 +++++++++--
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 90761ee97..1a3c05be7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,6 +22,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 - Fix bug in relation detection when selecting parents two levels up by using the name of the FK - @ruslantalpa
 - Customize content negotiation per route - @begriffs
 - Allow using nulls order without explicit order direction - @steve-chavez
+- Fatal error on postgres unsupported version, format supported version in error message - @steve-chavez
 
 ### Changed
 - Use HTTP 400 for raise\_exception - @begriffs
diff --git a/main/Main.hs b/main/Main.hs
index 9140a33db..a72235efb 100644
--- a/main/Main.hs
+++ b/main/Main.hs
@@ -5,6 +5,7 @@ module Main where
 import           Protolude
 import           PostgREST.App
 import           PostgREST.Config                     (AppConfig (..),
+                                                       PgVersion (..),
                                                        minimumPgVersion,
                                                        prettyVersion,
                                                        readOptions)
@@ -34,11 +35,11 @@ import           System.Posix.Signals
 isServerVersionSupported :: H.Session Bool
 isServerVersionSupported = do
   ver <- H.query () pgVersion
-  return $ toInteger ver >= minimumPgVersion
+  return $ ver >= pgvNum minimumPgVersion
  where
   pgVersion =
-    H.statement "SHOW server_version_num"
-      HE.unit (HD.singleRow $ HD.value HD.int4) True
+    H.statement "SELECT current_setting('server_version_num')::integer"
+      HE.unit (HD.singleRow $ HD.value HD.int4) False
 
 main :: IO ()
 main = do
@@ -67,7 +68,7 @@ main = do
     supported <- isServerVersionSupported
     unless supported $ panic (
       "Cannot run in this PostgreSQL version, PostgREST needs at least "
-      <> show minimumPgVersion)
+      <> pgvName minimumPgVersion)
     getDbStructure (toS $ configSchema conf)
 
   forM_ (lefts [result]) $ \e -> do
diff --git a/src/PostgREST/Config.hs b/src/PostgREST/Config.hs
index c6beec133..26f3f2697 100644
--- a/src/PostgREST/Config.hs
+++ b/src/PostgREST/Config.hs
@@ -16,6 +16,7 @@ module PostgREST.Config ( prettyVersion
                         , readOptions
                         , corsPolicy
                         , minimumPgVersion
+                        , PgVersion (..)
                         , AppConfig (..)
                         )
        where
@@ -171,6 +172,12 @@ argParser = CmdArgs <$>
       help "Path to configuration file")) <*>
   switch (long "example-config" <> help "output an example config file")
 
+
+data PgVersion = PgVersion {
+  pgvNum  :: Int32
+, pgvName :: Text
+}
+
 -- | Tells the minimum PostgreSQL version required by this version of PostgREST
-minimumPgVersion :: Integer
-minimumPgVersion = 90300
+minimumPgVersion :: PgVersion
+minimumPgVersion = PgVersion 90300 "9.3"