From 9ebb45746bbb04b1f44692f0f00aed9cfd67d3dd Mon Sep 17 00:00:00 2001
From: Andres Freund <andres@anarazel.de>
Date: Wed, 10 Jun 2026 13:09:10 -0400
Subject: [PATCH v13a 8/9] ci: Make runs-on overridable

Previously what runners CI ran on was hardcoded. Unfortunately that makes it
harder to use faster or self hosted runners (e.g. in a private repository
where the runners are very slow, or self hosted runners for cfbot).

Fix that by allowing to override the runner types via repository/organization
variables. How to do that is documented in src/tools/ci/README.

Testing faster github hosted runners showed that we have some dependencies on
specific locations, fix most of those. The remainder will be in a separate
commit, changing how we deal with the msys2 installation.

Discussion: https://postgr.es/m/a2ejn7lfqolutzz7kozalbhy3bixdrujb4buc3pgbtlk4am2ba@wbv6v7riia33
---
 .github/workflows/pg-ci.yml | 60 ++++++++++++++++++++++++-------------
 src/tools/ci/README         | 21 +++++++++++++
 2 files changed, 60 insertions(+), 21 deletions(-)

diff --git a/.github/workflows/pg-ci.yml b/.github/workflows/pg-ci.yml
index 9384ec0d902..c737173abe0 100644
--- a/.github/workflows/pg-ci.yml
+++ b/.github/workflows/pg-ci.yml
@@ -106,12 +106,6 @@ env:
     --with-uuid=ossp
     --with-zstd
 
-  # Centrally define the version of linux runners, to make it easier to
-  # update. We don't just want to use ubuntu-latest, as it's not implausible
-  # there will be breakage when that switches to the next ubuntu version.
-  _LINUX_RUNS_ON: &linux_runs_on |
-    ubuntu-24.04
-
   # Debian Trixie containers used by all Linux jobs. Built by
   # 'https://github.com/anarazel/pg-vm-images/'.
   CONTAINER_REPO: ghcr.io/anarazel/pg-vm-images/main
@@ -154,7 +148,8 @@ jobs:
   warn-if-not-opted-in:
     name: Report if not opted into CI
     if: ${{vars.PG_CI_ENABLED != '1'}}
-    runs-on: ubuntu-slim
+    # See the setup task for an explanation
+    runs-on: ${{ case(vars.pg_ci_runs_on_setup != '', vars.pg_ci_runs_on_setup, 'ubuntu-slim') }}
     steps:
       - name: Warn
         env:
@@ -184,21 +179,43 @@ jobs:
     # Only run CI if repo owner opted in. If this task is skipped due to the
     # if, none of it's depending tasks (i.e. the actual CI tasks) run either.
     if: ${{vars.PG_CI_ENABLED == '1'}}
-    runs-on: *linux_runs_on
     timeout-minutes: 1
     outputs:
+      # Are certain tasks enabled?
       linux: ${{ steps.os.outputs.linux }}
       macos: ${{ steps.os.outputs.macos }}
       windows: ${{ steps.os.outputs.windows }}
       mingw: ${{ steps.os.outputs.mingw }}
       compilerwarnings: ${{ steps.os.outputs.compilerwarnings }}
       sanitycheck: ${{ steps.os.outputs.sanitycheck }}
+
+      # What runners to run on:
+      #
+      # To allow over-riding what runners jobs use, we allow setting
+      # repository / org level variables influencing that choice on a
+      # per-host-operating-system basis.
+      #
+      # This also makes it easier to change the version of linux / windows
+      # used centrally. We don't just want to use ubuntu-latest, as it's not
+      # implausible there will be breakage when that switches to the next
+      # ubuntu version.
+      runs_on_linux: ${{ case(vars.PG_CI_RUNS_ON_LINUX != '', vars.PG_CI_RUNS_ON_LINUX, 'ubuntu-24.04') }}
+      runs_on_windows: ${{ case(vars.PG_CI_RUNS_ON_WINDOWS != '', vars.PG_CI_RUNS_ON_WINDOWS, 'windows-2022') }}
+      runs_on_macos: ${{ case(vars.PG_CI_RUNS_ON_MACOS != '', vars.PG_CI_RUNS_ON_MACOS, 'macos-15') }}
+      # runs_on_setup: an output can't be used as the input of the setup job
+      # itself, so it's done inline below.
+
+      # Exports:
+      #
       # Re-export workflow-level env vars that other jobs need to reference
       # from contexts (e.g. `jobs.<id>.container.image`) where the `env`
       # context is not available.
       container_linux_ci: ${{ env.CONTAINER_REPO }}/${{ env.CONTAINER_LINUX_CI }}
       container_linux_ci_docs: ${{ env.CONTAINER_REPO }}/${{ env.CONTAINER_LINUX_CI_DOCS }}
 
+    # Can't use the output from above, so repeated verbatim here
+    runs-on: ${{ case(vars.pg_ci_runs_on_setup != '', vars.pg_ci_runs_on_setup, 'ubuntu-slim') }}
+
     steps:
       # Anchor reused by other jobs further down. GitHub Actions supports YAML
       # anchors/aliases but not merge keys, so the alias copies the whole step
@@ -258,7 +275,7 @@ jobs:
     if: |
       !cancelled() &&
       needs.setup.outputs.sanitycheck == 'true'
-    runs-on: *linux_runs_on
+    runs-on: ${{ needs.setup.outputs.runs_on_linux }}
     timeout-minutes: 15
     container: &linux_ci_container
       image: ${{ needs.setup.outputs.container_linux_ci }}
@@ -446,7 +463,7 @@ jobs:
       !cancelled() &&
       needs.setup.outputs.linux == 'true' &&
       needs.sanity-check.result != 'failure'
-    runs-on: *linux_runs_on
+    runs-on: ${{ needs.setup.outputs.runs_on_linux }}
     container: *linux_ci_container
     timeout-minutes: 60
 
@@ -540,7 +557,7 @@ jobs:
     name: Linux - Meson (32-bit)
     needs: [setup, sanity-check]
     if: *linux_job_if
-    runs-on: *linux_runs_on
+    runs-on: ${{ needs.setup.outputs.runs_on_linux }}
     container: *linux_ci_container
     timeout-minutes: 60
     env: *linux_env
@@ -632,7 +649,7 @@ jobs:
     name: Linux - Meson (64-bit)
     needs: [setup, sanity-check]
     if: *linux_job_if
-    runs-on: *linux_runs_on
+    runs-on: ${{ needs.setup.outputs.runs_on_linux }}
     container: *linux_ci_container
     timeout-minutes: 60
     env: *linux_env
@@ -688,7 +705,7 @@ jobs:
       !cancelled() &&
       needs.setup.outputs.macos == 'true' &&
       needs.sanity-check.result != 'failure'
-    runs-on: macos-15
+    runs-on: ${{ needs.setup.outputs.runs_on_macos }}
     timeout-minutes: 60
     env:
       MACPORTS_CACHE: ${{ github.workspace }}/macports-cache
@@ -845,7 +862,7 @@ jobs:
       !cancelled() &&
       needs.setup.outputs.windows == 'true' &&
       needs.sanity-check.result != 'failure'
-    runs-on: windows-2022
+    runs-on: ${{ needs.setup.outputs.runs_on_windows }}
     timeout-minutes: 60
 
     # As described at the top of the task, split the tests across two runners
@@ -861,7 +878,7 @@ jobs:
     env:
       # Avoid port conflicts between concurrent tap tests
       PG_TEST_USE_UNIX_SOCKETS: 1
-      PG_REGRESS_SOCK_DIR: 'd:\pgsock'
+      PG_REGRESS_SOCK_DIR: ${{ github.workspace }}/pgsock
       TAR: "c:/windows/system32/tar.exe"
 
       MESON_FEATURES: >-
@@ -967,7 +984,8 @@ jobs:
       - name: Install dependencies
         shell: pwsh
         run: |
-          # meson is not preinstalled on windows-2022. Install via pip
+          # meson is not preinstalled, at least on windows-2022. Install via
+          # pip
           echo ::group::pip
           python -m pip install --upgrade meson
           if (!$?) { throw 'cmdfail' }
@@ -999,7 +1017,7 @@ jobs:
 
       - name: Setup socket directory
         shell: cmd
-        run: mkdir ${{env.PG_REGRESS_SOCK_DIR}}
+        run: mkdir "${{env.PG_REGRESS_SOCK_DIR}}"
 
       - &windows_setup_debugger_step
         name: Setup Windows debugger
@@ -1046,12 +1064,12 @@ jobs:
       !cancelled() &&
       needs.setup.outputs.mingw == 'true' &&
       needs.sanity-check.result != 'failure'
-    runs-on: windows-2022
+    runs-on: ${{ needs.setup.outputs.runs_on_windows }}
     timeout-minutes: 60
     env:
       # Avoid port conflicts between concurrent tap tests
       PG_TEST_USE_UNIX_SOCKETS: 1
-      PG_REGRESS_SOCK_DIR: 'd:\pgsock'
+      PG_REGRESS_SOCK_DIR: ${{ github.workspace }}/pgsock
       TAR: "c:/windows/system32/tar.exe"
 
       MSYS: winjitdebug
@@ -1127,7 +1145,7 @@ jobs:
 
       - name: Setup socket directory
         shell: cmd
-        run: mkdir ${{env.PG_REGRESS_SOCK_DIR}}
+        run: mkdir "${{env.PG_REGRESS_SOCK_DIR}}"
 
       - *windows_setup_debugger_step
 
@@ -1173,7 +1191,7 @@ jobs:
       !cancelled() &&
       needs.setup.outputs.compilerwarnings == 'true' &&
       needs.sanity-check.result != 'failure'
-    runs-on: *linux_runs_on
+    runs-on: ${{ needs.setup.outputs.runs_on_linux }}
     timeout-minutes: 60
     container:
       image: ${{ needs.setup.outputs.container_linux_ci_docs }}
diff --git a/src/tools/ci/README b/src/tools/ci/README
index 642e518c296..9276d4a654c 100644
--- a/src/tools/ci/README
+++ b/src/tools/ci/README
@@ -75,3 +75,24 @@ messages. Currently the following controls are available:
 
   Only runs CI on operating systems specified. This can be useful when
   addressing portability issues affecting only a subset of platforms.
+
+
+Controlling which runners CI uses
+=================================
+
+By default each job runs on a GitHub-hosted runner appropriate for its
+operating system. This can be overridden on a per-operating-system basis by
+creating repository or organization variables, at
+https://github.com/<username>/<reponame>/settings/variables/actions
+
+This is useful to run on faster GitHub-hosted runners, or on self-hosted
+runners.
+
+The following variables are recognized. If a variable is unset or empty, a
+default runner suitable for that operating system is used:
+
+- PG_CI_RUNS_ON_LINUX:   Linux jobs, including SanityCheck and CompilerWarnings
+- PG_CI_RUNS_ON_WINDOWS: the Windows (VS) and MinGW jobs
+- PG_CI_RUNS_ON_MACOS:   the macOS job
+- PG_CI_RUNS_ON_SETUP:   the lightweight bookkeeping jobs (opt-in warning and
+                         job setup)
-- 
2.54.0.450.g9ac3f193c0

