postgresqlTestHook: init

doc/hooks/index.xml

@@ -0,0 +1,10 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="chap-hooks">
+ <title>Hooks reference</title>
+ <para>
+  Nixpkgs has several hook functions that add augment the stdenv phases.
+ </para>
+ <xi:include href="./postgresql-test-hook.section.xml" />
+</chapter>

doc/hooks/postgresql-test-hook.section.md

@@ -0,0 +1,59 @@
+
+# `postgresqlTestHook` {#sec-postgresqlTestHook}
+
+This hook starts a PostgreSQL server during the `checkPhase`. Example:
+
+```nix
+{ stdenv, postgresql, postgresqlTestHook }:
+stdenv.mkDerivation {
+
+  # ...
+
+  checkInputs = [
+    postgresql
+    postgresqlTestHook
+  ];
+}
+```
+
+If you use a custom `checkPhase`, remember to add the `runHook` calls:
+```nix
+  checkPhase ''
+    runHook preCheck
+
+    # ... your tests
+
+    runHook postCheck
+  ''
+```
+
+## Variables {#sec-postgresqlTestHook-variables}
+
+The hook logic will read a number of variables and set them to a default value if unset or empty.
+
+Exported variables:
+
+ - `PGDATA`: location of server files.
+ - `PGHOST`: location of UNIX domain socket directory; the default `host` in a connection string.
+ - `PGUSER`: user to create / log in with, default: `test_user`.
+ - `PGDATABASE`: database name, default: `test_db`.
+
+Bash-only variables:
+
+ - `postgresqlTestUserOptions`: SQL options to use when creating the `$PGUSER` role, default: `LOGIN`.
+ - `postgresqlTestSetupSQL`: SQL commands to run as database administrator after startup, default: statements that create `$PGUSER` and `$PGDATABASE`.
+ - `postgresqlTestSetupCommands`: bash commands to run after database start, defaults to running `$postgresqlTestSetupSQL` as database administrator.
+ - `postgresqlEnableTCP`: set to `1` to enable TCP listening. Flaky; not recommended.
+ - `postgresqlStartCommands`: defaults to `pg_ctl start`.
+
+## TCP and the Nix sandbox {#sec-postgresqlTestHook-tcp}
+
+`postgresqlEnableTCP` relies on network sandboxing, which is not available on macOS and some custom Nix installations, resulting in flaky tests.
+For this reason, it is disabled by default.
+
+The preferred solution is to make the test suite use a UNIX domain socket connection. This is the default behavior when no `host` connection parameter is provided.
+Some test suites hardcode a value for `host` though, so a patch may be required. If you can upstream the patch, you can make `host` default to the `PGHOST` environment variable when set. Otherwise, you can patch it locally to omit the `host` connection string parameter altogether.
+
+::: {.note}
+The error `libpq: failed (could not receive data from server: Connection refused` is generally an indication that the test suite is trying to connect through TCP.
+:::

doc/manual.xml

@@ -27,6 +27,7 @@
   <xi:include href="builders/trivial-builders.chapter.xml" />
   <xi:include href="builders/special.xml" />
   <xi:include href="builders/images.xml" />
+  <xi:include href="hooks/index.xml" />
   <xi:include href="languages-frameworks/index.xml" />
   <xi:include href="builders/packages/index.xml" />
  </part>

pkgs/build-support/setup-hooks/postgresql-test-hook/default.nix

@@ -0,0 +1,9 @@
+{ callPackage, makeSetupHook }:
+
+(makeSetupHook {
+  name = "postgresql-test-hook";
+} ./postgresql-test-hook.sh).overrideAttrs (o: {
+  passthru.tests = {
+    simple = callPackage ./test.nix { };
+  };
+})

pkgs/build-support/setup-hooks/postgresql-test-hook/postgresql-test-hook.sh

@@ -0,0 +1,79 @@
+preCheckHooks+=('postgresqlStart')
+postCheckHooks+=('postgresqlStop')
+
+
+postgresqlStart() {
+
+  # Add default environment variable values
+  #
+  # Client variables:
+  #  - https://www.postgresql.org/docs/current/libpq-envars.html
+  #
+  # Server variables:
+  #  - only PGDATA: https://www.postgresql.org/docs/current/creating-cluster.html
+
+  if [[ "${PGDATA:-}" == "" ]]; then
+    PGDATA="$NIX_BUILD_TOP/postgresql"
+  fi
+  export PGDATA
+
+  if [[ "${PGHOST:-}" == "" ]]; then
+    mkdir -p "$NIX_BUILD_TOP/run/postgresql"
+    PGHOST="$NIX_BUILD_TOP/run/postgresql"
+  fi
+  export PGHOST
+
+  if [[ "${PGUSER:-}" == "" ]]; then
+    PGUSER="test_user"
+  fi
+  export PGUSER
+
+  if [[ "${PGDATABASE:-}" == "" ]]; then
+    PGDATABASE="test_db"
+  fi
+  export PGDATABASE
+
+  if [[ "${postgresqlTestUserOptions:-}" == "" ]]; then
+    postgresqlTestUserOptions="LOGIN"
+  fi
+
+  if [[ "${postgresqlTestSetupSQL:-}" == "" ]]; then
+    postgresqlTestSetupSQL="$(cat <<EOF
+      CREATE ROLE "$PGUSER" $postgresqlTestUserOptions;
+      CREATE DATABASE "$PGDATABASE" OWNER '$PGUSER';
+EOF
+    )"
+  fi
+
+  if [[ "${postgresqlTestSetupCommands:-}" == "" ]]; then
+    postgresqlTestSetupCommands='echo "$postgresqlTestSetupSQL" | PGUSER=postgres psql postgres'
+  fi
+
+  if ! type initdb >/dev/null; then
+    echo >&2 'initdb not found. Did you add postgresql to the checkInputs?'
+    false
+  fi
+  header 'initializing postgresql'
+  initdb -U postgres
+
+  # Move the socket
+  echo "unix_socket_directories = '$NIX_BUILD_TOP/run/postgresql'" >>"$PGDATA/postgresql.conf"
+
+  # TCP ports can be a problem in some sandboxes,
+  # so we disable tcp listening by default
+  if ! [[ "${postgresqlEnableTCP:-}" = 1 ]]; then
+    echo "listen_addresses = ''" >>"$PGDATA/postgresql.conf"
+  fi
+
+  header 'starting postgresql'
+  eval "${postgresqlStartCommands:-pg_ctl start}"
+
+  header 'setting up postgresql'
+  eval "$postgresqlTestSetupCommands"
+
+}
+
+postgresqlStop() {
+  header 'stopping postgresql'
+  pg_ctl stop
+}

pkgs/build-support/setup-hooks/postgresql-test-hook/test.nix

@@ -0,0 +1,27 @@
+{ postgresql, postgresqlTestHook, stdenv }:
+
+stdenv.mkDerivation {
+  name = "postgresql-test-hook-test";
+  buildInputs = [ postgresqlTestHook ];
+  checkInputs = [ postgresql ];
+  dontUnpack = true;
+  doCheck = true;
+  passAsFile = ["sql"];
+  sql = ''
+    CREATE TABLE hello (
+      message text
+    );
+    INSERT INTO hello VALUES ('it '||'worked');
+    SELECT * FROM hello;
+  '';
+  checkPhase = ''
+    runHook preCheck
+    psql <$sqlPath | grep 'it worked'
+    TEST_RAN=1
+    runHook postCheck
+  '';
+  installPhase = ''
+    [[ $TEST_RAN == 1 ]]
+    touch $out
+  '';
+}

pkgs/top-level/all-packages.nix

@@ -21965,6 +21965,8 @@ with pkgs;
 
   postgresql_jdbc = callPackage ../development/java-modules/postgresql_jdbc { };
 
+  postgresqlTestHook = callPackage ../build-support/setup-hooks/postgresql-test-hook { };
+
   prom2json = callPackage ../servers/monitoring/prometheus/prom2json.nix { };
   prometheus = callPackage ../servers/monitoring/prometheus { };
   prometheus-alertmanager = callPackage ../servers/monitoring/prometheus/alertmanager.nix { };