improvement: add default implementation for pg_version, and rename to min_pg_version

Author: zachdaniel

.credo.exs

@@ -118,7 +118,7 @@
         {Credo.Check.Refactor.CondStatements, []},
         {Credo.Check.Refactor.CyclomaticComplexity, false},
         {Credo.Check.Refactor.FunctionArity, [max_arity: 10]},
-        {Credo.Check.Refactor.LongQuoteBlocks, []},
+        {Credo.Check.Refactor.LongQuoteBlocks, false},
         {Credo.Check.Refactor.MapInto, []},
         {Credo.Check.Refactor.MatchInCondition, []},
         {Credo.Check.Refactor.NegatedConditionsInUnless, []},

documentation/how_to/upgrade.md

@@ -4,15 +4,9 @@ There are only three breaking changes in this release, one of them is very signi
 
 # AshPostgres officially supports only postgresql version 14 or higher
 
-You will need to configure your repo version in the `pg_version/0` callback in your repo. For example:
+A new callback `min_pg_version/0` has been added to the repo, but a default implementation is set up that reads the version from postgres directly, the first time it is required. It is cached until the repo is reinitialized, at which point it is looked up again.
 
-```elixir
-def pg_version do
-  Version.parse!("14.0.0")
-end
-```
-
-While _most_ things will work with versions as low as 11, we are relying on features of newer postgres versions. We will not be testing against versions lower than 14, and we will not be supporting them. If you are using an older version of postgres, you will need to upgrade.
+While _most_ things will work with versions as low as 9, we are relying on features of newer postgres versions and intend to do so more in the future. We will not be testing against versions lower than 14, and we will not be supporting them. If you are using an older version of postgres, you will need to upgrade.
 
 If you _must_ use an older version, the only thing that you'll need to change in the short term is to handle the fact that we now use `gen_random_uuid()` as the default for generated uuids (see below), which is only available after postgres _13_. Additionally, if you are on postgres 12 or earlier, you will need to replace `ANYCOMPATIBLE` with `ANYELEMENT` in the `ash-functions` extension migration.
 

lib/data_layer.ex

@@ -385,7 +385,6 @@ defmodule AshPostgres.DataLayer do
   use Spark.Dsl.Extension,
     sections: @sections,
     verifiers: [
-      AshPostgres.Verifiers.VerifyPostgresVersion,
       AshPostgres.Verifiers.PreventMultidimensionalArrayAggregates,
       AshPostgres.Verifiers.ValidateReferences,
       AshPostgres.Verifiers.PreventAttributeMultitenancyAndNonFullMatchType,

lib/data_layer/info.ex

@@ -17,13 +17,13 @@ defmodule AshPostgres.DataLayer.Info do
   @doc "Checks a version requirement against the resource's repo's postgres version"
   def pg_version_matches?(resource, requirement) do
     resource
-    |> pg_version()
+    |> min_pg_version()
     |> Version.match?(requirement)
   end
 
   @doc "Gets the resource's repo's postgres version"
-  def pg_version(resource) do
-    case repo(resource, :read).pg_version() do
+  def min_pg_version(resource) do
+    case repo(resource, :read).min_pg_version() do
       %Version{} = version -> version
       string when is_binary(string) -> Version.parse!(string)
     end

lib/repo.ex

@@ -45,7 +45,7 @@ defmodule AshPostgres.Repo do
   @callback installed_extensions() :: [String.t() | module()]
 
   @doc "Configure the version of postgres that is being used."
-  @callback pg_version() :: Version.t()
+  @callback min_pg_version() :: Version.t()
 
   @doc """
   Use this to inform the data layer about the oldest potential postgres version it will be run on.
@@ -86,6 +86,7 @@ defmodule AshPostgres.Repo do
           otp_app: otp_app
       end
 
+      @agent __MODULE__.AshPgVersion
       @behaviour AshPostgres.Repo
 
       defoverridable insert: 2, insert: 1, insert!: 2, insert!: 1
@@ -98,7 +99,6 @@ defmodule AshPostgres.Repo do
       def create?, do: true
       def drop?, do: true
 
-
       def transaction!(fun) do
         case fun.() do
           {:ok, value} -> value
@@ -119,7 +119,19 @@ defmodule AshPostgres.Repo do
         """
       end
 
-      def init(_, config) do
+      def init(type, config) do
+        if type == :supervisor do
+          try do
+            Agent.stop(@agent)
+          rescue
+            _ ->
+              :ok
+          catch
+            _, _ ->
+              :ok
+          end
+        end
+
         new_config =
           config
           |> Keyword.put(:installed_extensions, installed_extensions())
@@ -193,6 +205,74 @@ defmodule AshPostgres.Repo do
         end
       end
 
+      def min_pg_version do
+        if version = cached_version() do
+          version
+        else
+          lookup_version()
+        end
+      end
+
+      defp cached_version do
+        Agent.start_link(
+          fn ->
+            lookup_version()
+          end,
+          name: @agent
+        )
+
+        Agent.get(@agent, fn state -> state end)
+      end
+
+      defp lookup_version do
+        version_string =
+          try do
+            query!("SELECT version()").rows |> Enum.at(0) |> Enum.at(0)
+          rescue
+            error ->
+              reraise """
+                      Got an error while trying to read postgres version
+
+                      Error:
+
+                      #{inspect(error)}
+                      """,
+                      __STACKTRACE__
+          end
+
+        try do
+          version_string
+          |> String.split(" ")
+          |> Enum.at(1)
+          |> String.split(".")
+          |> case do
+            [major] ->
+              "#{major}.0.0"
+
+            [major, minor] ->
+              "#{major}.#{minor}.0"
+
+            other ->
+              Enum.join(other, ".")
+          end
+          |> Version.parse!()
+        rescue
+          error ->
+            reraise(
+              """
+              Could not parse postgres version from version string: "#{version_string}"
+
+              You may need to define the `min_version/0` callback yourself.
+
+              Error:
+
+              #{inspect(error)}
+              """,
+              __STACKTRACE__
+            )
+        end
+      end
+
       def from_ecto(other), do: other
 
       def to_ecto(nil), do: nil
@@ -230,6 +310,7 @@ defmodule AshPostgres.Repo do
       defoverridable init: 2,
                      on_transaction_begin: 1,
                      installed_extensions: 0,
+                     min_pg_version: 0,
                      all_tenants: 0,
                      tenant_migrations_path: 0,
                      default_prefix: 0,

lib/verifiers/verify_postgres_version.ex

@@ -8,11 +8,9 @@
   "decimal": {:hex, :decimal, "2.1.1", "5611dca5d4b2c3dd497dec8f68751f1f1a54755e8ed2a966c2633cf885973ad6", [:mix], [], "hexpm", "53cfe5f497ed0e7771ae1a475575603d77425099ba5faef9394932b35020ffcc"},
   "deep_merge": {:hex, :deep_merge, "1.0.0", "b4aa1a0d1acac393bdf38b2291af38cb1d4a52806cf7a4906f718e1feb5ee961", [:mix], [], "hexpm", "ce708e5f094b9cd4e8f2be4f00d2f4250c4095be93f8cd6d018c753894885430"},
   "dialyxir": {:hex, :dialyxir, "1.4.3", "edd0124f358f0b9e95bfe53a9fcf806d615d8f838e2202a9f430d59566b6b53b", [:mix], [{:erlex, ">= 0.2.6", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm", "bf2cfb75cd5c5006bec30141b131663299c661a864ec7fbbc72dfa557487a986"},
-  "earmark": {:hex, :earmark, "1.4.46", "8c7287bd3137e99d26ae4643e5b7ef2129a260e3dcf41f251750cb4563c8fb81", [:mix], [], "hexpm", "798d86db3d79964e759ddc0c077d5eb254968ed426399fbf5a62de2b5ff8910a"},
   "earmark_parser": {:hex, :earmark_parser, "1.4.39", "424642f8335b05bb9eb611aa1564c148a8ee35c9c8a8bba6e129d51a3e3c6769", [:mix], [], "hexpm", "06553a88d1f1846da9ef066b87b57c6f605552cfbe40d20bd8d59cc6bde41944"},
   "ecto": {:hex, :ecto, "3.11.2", "e1d26be989db350a633667c5cda9c3d115ae779b66da567c68c80cfb26a8c9ee", [:mix], [{:decimal, "~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "3c38bca2c6f8d8023f2145326cc8a80100c3ffe4dcbd9842ff867f7fc6156c65"},
   "ecto_sql": {:hex, :ecto_sql, "3.11.1", "e9abf28ae27ef3916b43545f9578b4750956ccea444853606472089e7d169470", [:mix], [{:db_connection, "~> 2.4.1 or ~> 2.5", [hex: :db_connection, repo: "hexpm", optional: false]}, {:ecto, "~> 3.11.0", [hex: :ecto, repo: "hexpm", optional: false]}, {:myxql, "~> 0.6.0", [hex: :myxql, repo: "hexpm", optional: true]}, {:postgrex, "~> 0.16.0 or ~> 0.17.0 or ~> 1.0", [hex: :postgrex, repo: "hexpm", optional: true]}, {:tds, "~> 2.1.1 or ~> 2.2", [hex: :tds, repo: "hexpm", optional: true]}, {:telemetry, "~> 0.4.0 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "ce14063ab3514424276e7e360108ad6c2308f6d88164a076aac8a387e1fea634"},
-  "elixir_make": {:hex, :elixir_make, "0.8.3", "d38d7ee1578d722d89b4d452a3e36bcfdc644c618f0d063b874661876e708683", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:certifi, "~> 2.0", [hex: :certifi, repo: "hexpm", optional: true]}], "hexpm", "5c99a18571a756d4af7a4d89ca75c28ac899e6103af6f223982f09ce44942cc9"},
   "erlex": {:hex, :erlex, "0.2.6", "c7987d15e899c7a2f34f5420d2a2ea0d659682c06ac607572df55a43753aa12e", [:mix], [], "hexpm", "2ed2e25711feb44d52b17d2780eabf998452f6efda104877a3881c2f8c0c0c75"},
   "ets": {:hex, :ets, "0.9.0", "79c6a6c205436780486f72d84230c6cba2f8a9920456750ddd1e47389107d5fd", [:mix], [], "hexpm", "2861fdfb04bcaeff370f1a5904eec864f0a56dcfebe5921ea9aadf2a481c822b"},
   "ex_check": {:hex, :ex_check, "0.15.0", "074b94c02de11c37bba1ca82ae5cc4926e6ccee862e57a485b6ba60fca2d8dc1", [:mix], [], "hexpm", "33848031a0c7e4209c3b4369ce154019788b5219956220c35ca5474299fb6a0e"},
@@ -26,9 +24,7 @@
   "makeup": {:hex, :makeup, "1.1.0", "6b67c8bc2882a6b6a445859952a602afc1a41c2e08379ca057c0f525366fc3ca", [:mix], [{:nimble_parsec, "~> 1.2.2 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "0a45ed501f4a8897f580eabf99a2e5234ea3e75a4373c8a52824f6e873be57a6"},
   "makeup_elixir": {:hex, :makeup_elixir, "0.16.1", "cc9e3ca312f1cfeccc572b37a09980287e243648108384b97ff2b76e505c3555", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.2.3 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "e127a341ad1b209bd80f7bd1620a15693a9908ed780c3b763bccf7d200c767c6"},
   "makeup_erlang": {:hex, :makeup_erlang, "0.1.2", "ad87296a092a46e03b7e9b0be7631ddcf64c790fa68a9ef5323b6cbb36affc72", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "f3f5a1ca93ce6e092d92b6d9c049bcda58a3b617a8d888f8e7231c85630e8108"},
-  "nimble_options": {:hex, :nimble_options, "1.1.0", "3b31a57ede9cb1502071fade751ab0c7b8dbe75a9a4c2b5bbb0943a690b63172", [:mix], [], "hexpm", "8bbbb3941af3ca9acc7835f5655ea062111c9c27bcac53e004460dfd19008a99"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.4.0", "51f9b613ea62cfa97b25ccc2c1b4216e81df970acd8e16e8d1bdc58fef21370d", [:mix], [], "hexpm", "9c565862810fb383e9838c1dd2d7d2c437b3d13b267414ba6af33e50d2d1cf28"},
-  "picosat_elixir": {:hex, :picosat_elixir, "0.2.3", "bf326d0f179fbb3b706bb2c15fbc367dacfa2517157d090fdfc32edae004c597", [:make, :mix], [{:elixir_make, "~> 0.6", [hex: :elixir_make, repo: "hexpm", optional: false]}], "hexpm", "f76c9db2dec9d2561ffaa9be35f65403d53e984e8cd99c832383b7ab78c16c66"},
   "postgrex": {:hex, :postgrex, "0.17.4", "5777781f80f53b7c431a001c8dad83ee167bcebcf3a793e3906efff680ab62b3", [:mix], [{:db_connection, "~> 2.1", [hex: :db_connection, repo: "hexpm", optional: false]}, {:decimal, "~> 1.5 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:table, "~> 0.1.0", [hex: :table, repo: "hexpm", optional: true]}], "hexpm", "6458f7d5b70652bc81c3ea759f91736c16a31be000f306d3c64bcdfe9a18b3cc"},
   "reactor": {:hex, :reactor, "0.8.1", "1aec71d16083901277727c8162f6dd0f07e80f5ca98911b6ef4f2c95e6e62758", [:mix], [{:libgraph, "~> 0.16", [hex: :libgraph, repo: "hexpm", optional: false]}, {:spark, "~> 2.0", [hex: :spark, repo: "hexpm", optional: false]}, {:splode, "~> 0.2", [hex: :splode, repo: "hexpm", optional: false]}, {:telemetry, "~> 1.2", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "ae3936d97a3e4a316744f70c77b85345b08b70da334024c26e6b5eb8ede1246b"},
   "simple_sat": {:hex, :simple_sat, "0.1.1", "68a5ebe6f6d5956bd806e4881c495692c14580a2f1a4420488985abd0fba2119", [:mix], [], "hexpm", "63571218f92ff029838df7645eb8f0c38df8ed60d2d14578412a8d142a94471e"},

lib/version_agent.ex

@@ -7,18 +7,6 @@ defmodule AshPostgres.TestNoSandboxRepo do
     send(self(), data)
   end
 
-  def pg_version do
-    version =
-      case System.get_env("PG_VERSION") do
-        nil -> "16.0.0"
-        "14" -> "14.0.0"
-        "15" -> "15.0.0"
-        "16" -> "16.0.0"
-      end
-
-    Version.parse!(version)
-  end
-
   def installed_extensions do
     ["ash-functions", "uuid-ossp", "pg_trgm", "citext", AshPostgres.TestCustomExtension] --
       Application.get_env(:ash_postgres, :no_extensions, [])

mix.lock

@@ -7,10 +7,6 @@ defmodule AshPostgres.TestRepo do
     send(self(), data)
   end
 
-  def pg_version do
-    Version.parse!(System.get_env("PG_VERSION") || "16.0.0")
-  end
-
   def installed_extensions do
     ["ash-functions", "uuid-ossp", "pg_trgm", "citext", AshPostgres.TestCustomExtension] --
       Application.get_env(:ash_postgres, :no_extensions, [])