From c872f537375416289d3fdc302716403266899c1f Mon Sep 17 00:00:00 2001
From: Andres Freund <andres@anarazel.de>
Date: Fri, 12 Apr 2024 18:18:34 -0700
Subject: [PATCH v5] ci: Simplify ci-os-only handling

Handle 'ci-os-only' occurrences in the .cirrus.star file instead of
.cirrus.tasks.yml file. Now, 'ci-os-only' occurrences are controlled
from one central place instead of dealing with them in each task.

Author: Andres Freund <andres@anarazel.de>
Reviewed-by: Nazir Bilal Yavuz <byavuz81@gmail.com>
Discussion: https://postgr.es/m/20240413021221.hg53rvqlvldqh57i%40awork3.anarazel.de
Backpatch: 15-, where CI support was added
---
 .cirrus.star      | 52 +++++++++++++++++++++++++++++++++++++++++++----
 .cirrus.tasks.yml | 10 ++++-----
 .cirrus.yml       | 12 +++++++++--
 3 files changed, 63 insertions(+), 11 deletions(-)

diff --git a/.cirrus.star b/.cirrus.star
index d2d6ceca207..3264ce014c5 100644
--- a/.cirrus.star
+++ b/.cirrus.star
@@ -7,7 +7,7 @@ https://github.com/bazelbuild/starlark/blob/master/spec.md
 See also .cirrus.yml and src/tools/ci/README
 """
 
-load("cirrus", "env", "fs")
+load("cirrus", "env", "fs", "re", "yaml")
 
 
 def main():
@@ -18,19 +18,36 @@ def main():
 
     1) the contents of .cirrus.yml
 
-    2) if defined, the contents of the file referenced by the, repository
+    2) computed environment variables
+
+    3) if defined, the contents of the file referenced by the, repository
        level, REPO_CI_CONFIG_GIT_URL variable (see
        https://cirrus-ci.org/guide/programming-tasks/#fs for the accepted
        format)
 
-    3) .cirrus.tasks.yml
+    4) .cirrus.tasks.yml
     """
 
     output = ""
 
     # 1) is evaluated implicitly
 
+
     # Add 2)
+    additional_env = compute_environment_vars()
+    env_fmt = """
+###
+# Computed environment variables start here
+###
+{0}
+###
+# Computed environment variables end here
+###
+"""
+    output += env_fmt.format(yaml.dumps({'env': additional_env}))
+
+
+    # Add 3)
     repo_config_url = env.get("REPO_CI_CONFIG_GIT_URL")
     if repo_config_url != None:
         print("loading additional configuration from \"{}\"".format(repo_config_url))
@@ -38,12 +55,39 @@ def main():
     else:
         output += "\n# REPO_CI_CONFIG_URL was not set\n"
 
-    # Add 3)
+
+    # Add 4)
     output += config_from(".cirrus.tasks.yml")
 
+
     return output
 
 
+def compute_environment_vars():
+    cenv = {}
+
+    # Parse "ci-os-only:" tag in commit message and set
+    # CI_{$OS}_ENABLED variable for each OS
+
+    operating_systems = ['freebsd', 'linux', 'macos', 'windows', 'compilerwarnings']
+    commit_message = env.get('CIRRUS_CHANGE_MESSAGE')
+    match_re = r"(^|.*\n)ci-os-only: ([^\n]+)($|\n.*)"
+
+    # re.match() returns an array with a tuple of (matched-string, match_1, ...)
+    m = re.match(match_re, commit_message)
+    if m and len(m) > 0:
+        os_only = m[0][2]
+        os_only_list = re.split(r'[, ]+', os_only)
+    else:
+        os_only_list = operating_systems
+
+    for os in operating_systems:
+        os_enabled = os in os_only_list
+        cenv['CI_{0}_ENABLED'.format(os.upper())] = os_enabled
+
+    return cenv
+
+
 def config_from(config_src):
     """return contents of config file `config_src`, surrounded by markers
     indicating start / end of the the included file
diff --git a/.cirrus.tasks.yml b/.cirrus.tasks.yml
index 995ae7cefb9..ecf683b7b54 100644
--- a/.cirrus.tasks.yml
+++ b/.cirrus.tasks.yml
@@ -47,7 +47,7 @@ task:
 
   <<: *freebsd_task_template
 
-  only_if: $CIRRUS_CHANGE_MESSAGE !=~ '.*\nci-os-only:.*' || $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*freebsd.*'
+  only_if: $CI_FREEBSD_ENABLED
 
   sysinfo_script: |
     id
@@ -153,7 +153,7 @@ task:
 
   <<: *linux_task_template
 
-  only_if: $CIRRUS_CHANGE_MESSAGE !=~ '.*\nci-os-only:.*' || $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*linux.*'
+  only_if: $CI_LINUX_ENABLED
 
   ccache_cache:
     folder: ${CCACHE_DIR}
@@ -239,7 +239,7 @@ task:
 
   <<: *macos_task_template
 
-  only_if: $CIRRUS_CHANGE_MESSAGE !=~ '.*\nci-os-only:.*' || $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*(macos|darwin|osx).*'
+  only_if: $CI_MACOS_ENABLED
 
   sysinfo_script: |
     id
@@ -389,7 +389,7 @@ task:
 
   <<: *windows_task_template
 
-  only_if: $CIRRUS_CHANGE_MESSAGE !=~ '.*\nci-os-only:.*' || $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*windows.*'
+  only_if: $CI_WINDOWS_ENABLED
 
   sysinfo_script: |
     chcp
@@ -476,7 +476,7 @@ task:
 
   # task that did not run, count as a success, so we need to recheck Linux'
   # condition here ...
-  only_if: $CIRRUS_CHANGE_MESSAGE !=~ '.*\nci-os-only:.*' || $CIRRUS_CHANGE_MESSAGE =~ '.*\nci-os-only:[^\n]*linux.*'
+  only_if: $CI_COMPILERWARNINGS_ENABLED
 
   <<: *linux_task_template
 
diff --git a/.cirrus.yml b/.cirrus.yml
index a83129ae46d..f270f61241f 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -10,12 +10,20 @@
 #
 # 1) the contents of this file
 #
-# 2) if defined, the contents of the file referenced by the, repository
+# 2) computed environment variables
+#
+#    Used to enable/disable tasks based on the execution environment. See
+#    .cirrus.star: compute_environment_vars()
+#
+# 3) if defined, the contents of the file referenced by the, repository
 #    level, REPO_CI_CONFIG_GIT_URL variable (see
 #    https://cirrus-ci.org/guide/programming-tasks/#fs for the accepted
 #    format)
 #
-# 3) .cirrus.tasks.yml
+#    This allows running tasks in a different execution environment than the
+#    default, e.g. to have sufficient resources for cfbot.
+#
+# 4) .cirrus.tasks.yml
 #
 # This composition is done by .cirrus.star
 
-- 
2.49.0