Allow schema cache reloading with NOTIFY (#1542)

Fixes https://github.com/PostgREST/postgrest/issues/1512 Helps on environments where you can't send unix signals(Windows, managed containers). Also provides better UX for schema reloads - NOTIFY can be sent from pg clients(psql, pgadmin). `NOTIFY pgrst` - with no payload - should be done to reload the schema cache. Notifications with a payload will be ignored. The channel can be enabled with `db-channel-enabled`(false by default) and its name can be configured with `db-channel`. The LISTEN thread uses a dedicated pg connection. This connection is recovered if it fails. A debounce of 1ms is done in case too many NOTIFYs arrive.
2020-06-24 19:00:02 -05:00
parent 24064f8626
commit 43d71e95ac
13 changed files with 169 additions and 57 deletions
@@ -29,6 +29,8 @@ let
          "PGRST_DB_POOL=100"
          "PGRST_DB_POOL_TIMEOUT=10"
          "PGRST_DB_EXTRA_SEARCH_PATH=public"
+          "PGRST_DB_CHANNEL=pgrst"
+          "PGRST_DB_CHANNEL_ENABLED=false"
          "PGRST_SERVER_HOST=*4"
          "PGRST_SERVER_PORT=3000"
          "PGRST_OPENAPI_SERVER_PROXY_URI="
@@ -12,6 +12,9 @@ db-pool = "$(PGRST_DB_POOL)"
 db-pool-timeout = "$(PGRST_DB_POOL_TIMEOUT)"
 db-extra-search-path = "$(PGRST_DB_EXTRA_SEARCH_PATH)"

+db-channel = "$(PGRST_DB_CHANNEL)"
+db-channel-enabled = "$(PGRST_DB_CHANNEL_ENABLED)"
+
 server-host = "$(PGRST_SERVER_HOST)"
 server-port = "$(PGRST_SERVER_PORT)"

@@ -12,6 +12,19 @@ let
            ver = "0.3.0";
            sha256 = "0iwh4wsjhb7pms88lw1afhdal9f86nrrkkvv65f9wxbd1b159n72";
          } { };
+      # To get the sha256
+      # nix-prefetch-url --unpack https://hackage.haskell.org/package/hasql-notifications-0.1.0.0/hasql-notifications-0.1.0.0.tar.gz
+      hasql-notifications =
+        self.haskell.lib.overrideCabal
+          (
+            prev.callHackageDirect
+              {
+                pkg = "hasql-notifications";
+                ver = "0.1.0.0";
+                sha256 = "1z17gsqvvzzi0yipc3qy3jz8vzpww4vsc4vaj2kbzr2mfliq6fx3";
+              } { }
+          )
+          (old: { doCheck = false; });
    } // extraOverrides final prev;
 in
 {
@@ -31,4 +31,7 @@
  # https://github.com/nh2/static-haskell-nix/pull/91
  static-haskell-nix-postgrest-openssl-linking-fix =
    ./static-haskell-nix-postgrest-openssl-linking-fix.patch;
+
+  static-haskell-nix-hasql-notifications-openssl-linking-fix =
+    ./static-haskell-nix-hasql-notifications-openssl-linking-fix.patch;
 }
@@ -0,0 +1,28 @@
+From 49ecb703d9d0bfd38eb69ba5cb63a8262bd03f96 Mon Sep 17 00:00:00 2001
+From: steve-chavez <stevechavezast@gmail.com>
+Date: Thu, 11 Jun 2020 13:18:07 -0500
+Subject: [PATCH] Add hasql-notifications openssl linking fix
+
+---
+ survey/default.nix | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+diff --git a/survey/default.nix b/survey/default.nix
+index 828beaa..9c2d5f6 100644
+--- a/survey/default.nix
+++ b/survey/default.nix
+@@ -1054,6 +1054,11 @@ let
+                   super.squeal-postgresql
+                   [ final.openssl ]
+                   "--libs openssl";
+              hasql-notifications =
+                addStaticLinkerFlagsWithPkgconfig
+                  super.hasql-notifications
+                  [ final.openssl ]
+                  "--libs openssl";
+
+               xml-to-json =
+                 addStaticLinkerFlagsWithPkgconfig
+--
+2.19.3
+
@@ -18,6 +18,7 @@ let
      static-haskell-nix
      [
        patches.static-haskell-nix-postgrest-openssl-linking-fix
+        patches.static-haskell-nix-hasql-notifications-openssl-linking-fix
      ];

  patchedNixpkgs =