Limit PR checks to build only the modified images

.github/workflows/build-notebooks-pr.yaml

@@ -1,28 +1,40 @@
 ---
 "name": "Build Notebooks"
-"permissions":
-  "packages": "read"
 "on":
   "pull_request":
 
+permissions:
+  contents: read
+  packages: read
+  pull-requests: read
+
 jobs:
   gen:
     name: Generate job matrix
     runs-on: ubuntu-latest
     outputs:
       matrix: ${{ steps.gen.outputs.matrix }}
+      has_jobs: ${{ steps.gen.outputs.has_jobs }}
     steps:
       - uses: actions/checkout@v4
-      - run: python3 ci/cached-builds/gen_gha_matrix_jobs.py
+
+      - run: |
+          python3 ci/cached-builds/gen_gha_matrix_jobs.py \
+            --owner=${{ github.repository_owner }} \
+            --repo=${{ github.event.pull_request.base.repo.name }} \
+            --pr-number=${{ github.event.pull_request.number }} \
+            --skip-unchanged
         id: gen
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
-  # base images
   build:
     needs: ["gen"]
     strategy:
       fail-fast: false
       matrix: "${{ fromJson(needs.gen.outputs.matrix) }}"
     uses: ./.github/workflows/build-notebooks-TEMPLATE.yaml
+    if: ${{ fromJson(needs.gen.outputs.has_jobs) }}
     with:
       target: "${{ matrix.target }}"
       github: "${{ toJSON(github) }}"

Makefile

@@ -59,6 +59,7 @@ endef
 #   ARG 2: Path of image context we want to build.
 #   ARG 3: Base image tag name (optional).
 define image
+	$(info #*# Image build directory: <$(2)> #(MACHINE-PARSED LINE)#*#...)
 	$(call build_image,$(1),$(2),$(3))
 	$(call push_image,$(1))
 endef

ci/cached-builds/gen_gha_matrix_jobs.py

@@ -1,11 +1,17 @@
+import argparse
 import itertools
 import json
+import logging
 import os
 import pathlib
 import re
 import string
+import sys
+import unittest
 from typing import Iterable
 
+import gha_pr_changed_files
+
 """Trivial Makefile parser that extracts target dependencies so that we can build each Dockerfile image target in its
 own GitHub Actions job and handle dependencies between them.
 
@@ -115,11 +121,13 @@ def write_github_workflow_file(tree: dict[str, list[str]], path: pathlib.Path) -
 def flatten(list_of_lists):
     return list(itertools.chain.from_iterable(list_of_lists))
 
+
 def compute_leafs_in_dependency_tree(tree: dict[str, list[str]]) -> list[str]:
     key_set = set(tree.keys())
     value_set = set(flatten(tree.values()))
     return [key for key in key_set if key not in value_set]
 
+
 def print_github_actions_pr_matrix(tree: dict[str, list[str]], leafs: list[str]) -> list[str]:
     """Outputs GitHub matrix definition Json
     """
@@ -136,10 +144,24 @@ def print_github_actions_pr_matrix(tree: dict[str, list[str]], leafs: list[str])
         targets.append(leaf)
 
     matrix = {"target": targets}
-    return [f"matrix={json.dumps(matrix, separators=(',', ':'))}"]
+    return [f"matrix={json.dumps(matrix, separators=(',', ':'))}",
+            f"has_jobs={json.dumps(len(leafs) > 0, separators=(',', ':'))}"]
 
 
 def main() -> None:
+    logging.basicConfig(level=logging.DEBUG, stream=sys.stderr)
+
+    argparser = argparse.ArgumentParser()
+    argparser.add_argument("--owner", type=str, required=False,
+                           help="GitHub repo owner/org (for the --skip-unchanged feature)")
+    argparser.add_argument("--repo", type=str, required=False,
+                           help="GitHub repo name (for the --skip-unchanged feature)")
+    argparser.add_argument("--pr-number", type=int, required=False,
+                           help="PR number under owner/repo (for the --skip-unchanged feature)")
+    argparser.add_argument("--skip-unchanged", type=bool, required=False, default=False,
+                           action=argparse.BooleanOptionalAction)
+    args = argparser.parse_args()
+
     # https://www.gnu.org/software/make/manual/make.html#Reading-Makefiles
     with open("Makefile", "rt") as makefile:
         lines = read_makefile_lines(makefile)
@@ -148,6 +170,10 @@ def main() -> None:
     write_github_workflow_file(tree, project_dir / ".github" / "workflows" / "build-notebooks.yaml")
 
     leafs = compute_leafs_in_dependency_tree(tree)
+    if args.skip_unchanged:
+        logging.info(f"Skipping targets not modified in PR #{args.pr_number}")
+        changed_files = gha_pr_changed_files.list_changed_files(args.owner, args.repo, args.pr_number)
+        leafs = gha_pr_changed_files.filter_out_unchanged(leafs, changed_files)
     output = print_github_actions_pr_matrix(tree, leafs)
 
     print("leafs", leafs)
@@ -159,3 +185,18 @@ def main() -> None:
 
 if __name__ == '__main__':
     main()
+
+
+class SelfTests(unittest.TestCase):
+    def test_select_changed_targets(self):
+        with open(project_dir / "Makefile", "rt") as makefile:
+            lines = read_makefile_lines(makefile)
+        tree = extract_target_dependencies(lines)
+        leafs = compute_leafs_in_dependency_tree(tree)
+
+        changed_files = ["jupyter/datascience/ubi9-python-3.9/Dockerfile"]
+
+        leafs = gha_pr_changed_files.filter_out_unchanged(leafs, changed_files)
+        assert set(leafs) == {'cuda-jupyter-tensorflow-ubi9-python-3.9',
+                              'jupyter-trustyai-ubi9-python-3.9',
+                              'jupyter-pytorch-ubi9-python-3.9'}

ci/cached-builds/gha_pr_changed_files.py

@@ -0,0 +1,126 @@
+import json
+import logging
+import os
+import pathlib
+import re
+import subprocess
+import unittest
+import urllib.request
+
+PROJECT_ROOT = pathlib.Path(__file__).parent.parent.parent.resolve()
+
+
+def get_github_token() -> str:
+    github_token = os.environ['GITHUB_TOKEN']
+    return github_token
+
+
+# https://docs.github.com/en/graphql/guides/forming-calls-with-graphql
+def compose_gh_api_request(pull_number: int, owner="opendatahub-io", repo="notebooks", per_page=100,
+                           cursor="") -> urllib.request.Request:
+    github_token = get_github_token()
+
+    return urllib.request.Request(
+        url="https://api.github.com/graphql",
+        method="POST",
+        headers={
+            "Authorization": f"bearer {github_token}",
+        },
+        # https://docs.github.com/en/graphql/guides/using-the-explorer
+        data=json.dumps({"query": f"""
+{{
+  repository(owner:"{owner}", name:"{repo}") {{
+    pullRequest(number:{pull_number}) {{
+      files(first:{per_page}, after:"{cursor}") {{
+        edges {{
+          node {{
+            path
+          }}
+          cursor
+        }}
+      }}
+    }}
+  }}
+}}
+    """}).encode("utf-8"),
+    )
+
+
+def list_changed_files(owner: str, repo: str, pr_number: int, per_page=100) -> list[str]:
+    files = []
+
+    logging.debug("Getting list of changed files from GitHub API")
+
+    CURSOR = ""
+    while CURSOR is not None:
+        request = compose_gh_api_request(pull_number=pr_number, owner=owner, repo=repo, per_page=per_page,
+                                         cursor=CURSOR)
+        response = urllib.request.urlopen(request)
+        data = json.loads(response.read().decode("utf-8"))
+        response.close()
+        edges = data["data"]["repository"]["pullRequest"]["files"]["edges"]
+
+        CURSOR = None
+        for edge in edges:
+            files.append(edge["node"]["path"])
+            CURSOR = edge["cursor"]
+
+    logging.debug(f"Determined {len(files)} changed files: {files[:5]} (..., printing up to 5)")
+    return files
+
+
+def analyze_build_directories(make_target) -> list[str]:
+    directories = []
+
+    pattern = re.compile(r"#\*# Image build directory: <(?P<dir>[^>]+)> #\(MACHINE-PARSED LINE\)#\*#\.\.\.")
+    try:
+        logging.debug(f"Running make in --just-print mode for target {make_target}")
+        for line in subprocess.check_output(["make", make_target, "--just-print"], encoding="utf-8",
+                                            cwd=PROJECT_ROOT).splitlines():
+            if m := pattern.match(line):
+                directories.append(m["dir"])
+    except subprocess.CalledProcessError as e:
+        print(e.stderr, e.stdout)
+        raise
+
+    logging.debug(f"Target {make_target} depends on files in directories {directories}")
+    return directories
+
+
+def should_build_target(changed_files: list[str], target_directories: list[str]) -> str:
+    """Returns truthy if there is at least one changed file necessitating a build.
+    Falsy (empty) string is returned otherwise."""
+    for directory in target_directories:
+        for changed_file in changed_files:
+            if changed_file.startswith(directory):
+                return changed_file
+    return ""
+
+
+def filter_out_unchanged(targets: list[str], changed_files: list[str]) -> list[str]:
+    changed = []
+    for target in targets:
+        target_directories = analyze_build_directories(target)
+        if reason := should_build_target(changed_files, target_directories):
+            logging.info(f"✅ Will build {target} because file {reason} has been changed")
+            changed.append(target)
+        else:
+            logging.info(f"❌ Won't build {target}")
+    return changed
+
+
+class SelfTests(unittest.TestCase):
+    def test_compose_gh_api_request__call_without_asserting(self):
+        request = compose_gh_api_request(pull_number=556, per_page=100, cursor="")
+        print(request.data)
+
+    def test_list_changed_files__pagination_works(self):
+        changed_files = list_changed_files(owner="opendatahub-io", repo="notebooks", pr_number=556, per_page=1)
+        assert set(changed_files) == {'codeserver/ubi9-python-3.9/Dockerfile',
+                                      'codeserver/ubi9-python-3.9/run-code-server.sh'}
+
+    def test_analyze_build_directories(self):
+        directories = analyze_build_directories("jupyter-intel-pytorch-ubi9-python-3.9")
+        assert set(directories) == {"base/ubi9-python-3.9",
+                                    "intel/base/gpu/ubi9-python-3.9",
+                                    "jupyter/intel/pytorch/ubi9-python-3.9"}