[feat] Add new action for generating dynamic Gitlab pipelines

docs/manpage.rst

@@ -147,6 +147,14 @@ There are currently two actions that can be performed on tests: (a) list the tes
 An action must always be specified.
 
 
+.. option:: --ci-generate=FILE
+
+   Do not run the tests, but generate a Gitlab `child pipeline <https://docs.gitlab.com/ee/ci/parent_child_pipelines.html>`__ specification in ``FILE``.
+   You can set up your Gitlab CI to use the generated file to run every test as a separate Gitlab job respecting test dependencies.
+   For more information, have a look in :ref:`generate-ci-pipeline`.
+
+   .. versionadded:: 3.4.1
+
 .. option:: -l, --list
 
    List selected tests.

docs/tutorial_tips_tricks.rst

@@ -367,6 +367,8 @@ This option is useful when you combine it with the various test filtering option
 For example, you might want to rerun only the failed tests or just a specific test in a dependency chain.
 Let's see an artificial example that uses the following test dependency graph.
 
+.. _fig-deps-complex:
+
 .. figure:: _static/img/deps-complex.svg
    :align: center
 
@@ -477,3 +479,60 @@ If we tried to run :class:`T6` without restoring the session, we would have to r
 
    [  PASSED  ] Ran 5 test case(s) from 5 check(s) (0 failure(s))
    [==========] Finished on Thu Jan 21 14:32:09 2021
+
+
+.. _generate-ci-pipeline:
+
+Integrating into a CI pipeline
+------------------------------
+
+.. versionadded:: 3.4.1
+
+Instead of running your tests, you can ask ReFrame to generate a `child pipeline <https://docs.gitlab.com/ee/ci/parent_child_pipelines.html>`__ specification for the Gitlab CI.
+This will spawn a CI job for each ReFrame test respecting test dependencies.
+You could run your tests in a single job of your Gitlab pipeline, but you would not take advantage of the parallelism across different CI jobs.
+Having a separate CI job per test makes it also easier to spot the failing tests.
+
+As soon as you have set up a `runner <https://docs.gitlab.com/ee/ci/quick_start/>`__ for your repository, it is fairly straightforward to use ReFrame to automatically generate the necessary CI steps.
+The following is an example of ``.gitlab-ci.yml`` file that does exactly that:
+
+.. code-block:: yaml
+
+   stages:
+     - generate
+     - test
+
+   generate-pipeline:
+     stage: generate
+     script:
+       - reframe --ci-generate=${CI_PROJECT_DIR}/pipeline.yml -c ${CI_PROJECT_DIR}/path/to/tests
+     artifacts:
+       paths:
+         - ${CI_PROJECT_DIR}/pipeline.yml
+
+   test-jobs:
+     stage: test
+     trigger:
+       include:
+         - artifact: pipeline.yml
+           job: generate-pipeline
+       strategy: depend
+
+
+It defines two stages.
+The first one, called ``generate``, will call ReFrame to generate the pipeline specification for the desired tests.
+All the usual `test selection options <manpage.html#test-filtering>`__ can be used to select specific tests.
+ReFrame will process them as usual, but instead of running the selected tests, it will generate the correct steps for running each test individually as a Gitlab job.
+We then pass the generated CI pipeline file to second phase as an artifact and we are done!
+
+The following figure shows one part of the automatically generated pipeline for the test graph depicted `above <#fig-deps-complex>`__.
+
+.. figure:: _static/img/gitlab-ci.png
+   :align: center
+
+   :sub:`Snapshot of a Gitlab pipeline generated automatically by ReFrame.`
+
+
+.. note::
+
+   The ReFrame executable must be available in the Gitlab runner that will run the CI jobs.

reframe/core/exceptions.py

@@ -308,13 +308,8 @@ def is_severe(exc_type, exc_value, tb):
     '''Check if exception is a severe one.'''
 
     soft_errors = (ReframeError,
-                   ConnectionError,
-                   FileExistsError,
-                   FileNotFoundError,
-                   IsADirectoryError,
+                   OSError,
                    KeyboardInterrupt,
-                   NotADirectoryError,
-                   PermissionError,
                    TimeoutError)
     if isinstance(exc_value, soft_errors):
         return False

reframe/frontend/ci.py

@@ -0,0 +1,72 @@
+# Copyright 2016-2020 Swiss National Supercomputing Centre (CSCS/ETH Zurich)
+# ReFrame Project Developers. See the top-level LICENSE file for details.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+import sys
+import yaml
+
+import reframe.core.exceptions as errors
+import reframe.core.runtime as runtime
+
+
+def _emit_gitlab_pipeline(testcases):
+    config = runtime.runtime().site_config
+
+    # Collect the necessary ReFrame invariants
+    program = 'reframe'
+    prefix = 'rfm-stage/${CI_COMMIT_SHORT_SHA}'
+    checkpath = config.get('general/0/check_search_path')
+    recurse = config.get('general/0/check_search_recursive')
+
+    def rfm_command(testcase):
+        if config.filename != '<builtin>':
+            config_opt = f'-C {config.filename}'
+        else:
+            config_opt = ''
+
+        report_file = f'rfm-report-{testcase.level}.json'
+        if testcase.level:
+            restore_file = f'rfm-report-{testcase.level - 1}.json'
+        else:
+            restore_file = None
+
+        return ' '.join([
+            program,
+            f'--prefix={prefix}', config_opt,
+            f'{" ".join("-c " + c for c in checkpath)}',
+            f'-R' if recurse else '',
+            f'--report-file={report_file}',
+            f'--restore-session={restore_file}' if restore_file else '',
+            '-n', testcase.check.name, '-r'
+        ])
+
+    max_level = 0   # We need the maximum level to generate the stages section
+    json = {
+        'cache': {
+            'key': '${CI_COMMIT_REF_SLUG}',
+            'paths': ['rfm-stage/${CI_COMMIT_SHORT_SHA}']
+        },
+        'stages': []
+    }
+    for tc in testcases:
+        json[f'{tc.check.name}'] = {
+            'stage': f'rfm-stage-{tc.level}',
+            'script': [rfm_command(tc)],
+            'artifacts': {
+                'paths': [f'rfm-report-{tc.level}.json']
+            },
+            'needs': [t.check.name for t in tc.deps]
+        }
+        max_level = max(max_level, tc.level)
+
+    json['stages'] = [f'rfm-stage-{m}' for m in range(max_level+1)]
+    return json
+
+
+def emit_pipeline(fp, testcases, backend='gitlab'):
+    if backend != 'gitlab':
+        raise errors.ReframeError(f'unknown CI backend {backend!r}')
+
+    yaml.dump(_emit_gitlab_pipeline(testcases), stream=fp,
+              indent=2, sort_keys=False, width=sys.maxsize)

reframe/frontend/cli.py

@@ -21,6 +21,7 @@
 import reframe.core.runtime as runtime
 import reframe.core.warnings as warnings
 import reframe.frontend.argparse as argparse
+import reframe.frontend.ci as ci
 import reframe.frontend.dependencies as dependencies
 import reframe.frontend.filters as filters
 import reframe.frontend.runreport as runreport
@@ -119,7 +120,7 @@ def list_checks(testcases, printer, detailed=False):
     printer.info(
         '\n'.join(format_check(c, deps[c.name], detailed) for c in checks)
     )
-    printer.info(f'Found {len(checks)} check(s)')
+    printer.info(f'Found {len(checks)} check(s)\n')
 
 
 def logfiles_message():
@@ -272,6 +273,11 @@ def main():
         '-r', '--run', action='store_true',
         help='Run the selected checks'
     )
+    action_options.add_argument(
+        '--ci-generate', action='store', metavar='FILE',
+        help=('Generate into FILE a Gitlab CI pipeline '
+              'for the selected tests and exit'),
+    )
 
     # Run options
     run_options.add_argument(
@@ -334,6 +340,8 @@ def main():
         '--disable-hook', action='append', metavar='NAME', dest='hooks',
         default=[], help='Disable a pipeline hook for this run'
     )
+
+    # Environment options
     env_options.add_argument(
         '-M', '--map-module', action='append', metavar='MAPPING',
         dest='module_mappings', default=[],
@@ -795,9 +803,23 @@ def _case_failed(t):
             list_checks(testcases, printer, options.list_detailed)
             sys.exit(0)
 
+        if options.ci_generate:
+            list_checks(testcases, printer)
+            printer.info('[Generate CI]')
+            with open(options.ci_generate, 'wt') as fp:
+                ci.emit_pipeline(fp, testcases)
+
+            printer.info(
+                f'  Gitlab pipeline generated successfully '
+                f'in {options.ci_generate!r}.\n'
+            )
+            sys.exit(0)
+
         if not options.run:
-            printer.error(f"No action specified. Please specify `-l'/`-L' for "
-                          f"listing or `-r' for running. "
+            printer.error("No action option specified. Available options:\n"
+                          "  - `-l'/`-L' for listing\n"
+                          "  - `-r' for running\n"
+                          "  - `--ci-generate' for generating a CI pipeline\n"
                           f"Try `{argparser.prog} -h' for more options.")
             sys.exit(1)
 

reframe/frontend/dependencies.py

@@ -170,7 +170,8 @@ def validate_deps(graph):
                 if n in path:
                     cycle_str = '->'.join(path + [n])
                     raise DependencyError(
-                        'found cyclic dependency between tests: ' + cycle_str)
+                        'found cyclic dependency between tests: ' + cycle_str
+                    )
 
                 if n not in visited:
                     unvisited.append((n, node))
@@ -212,6 +213,7 @@ def toposort(graph, is_subgraph=False):
     '''
     test_deps = _reduce_deps(graph)
     visited = util.OrderedSet()
+    levels = {}
 
     def retrieve(d, key, default):
         try:
@@ -229,9 +231,15 @@ def visit(node, path):
         path.add(node)
 
         # Do a DFS visit of all the adjacent nodes
-        for adj in retrieve(test_deps, node, []):
-            if adj not in visited:
-                visit(adj, path)
+        adjacent = retrieve(test_deps, node, [])
+        for u in adjacent:
+            if u not in visited:
+                visit(u, path)
+
+        if adjacent:
+            levels[node] = max(levels[u] for u in adjacent) + 1
+        else:
+            levels[node] = 0
 
         path.pop()
         visited.add(node)
@@ -243,6 +251,7 @@ def visit(node, path):
     # Index test cases by test name
     cases_by_name = {}
     for c in graph.keys():
+        c.level = levels[c.check.name]
         try:
             cases_by_name[c.check.name].append(c)
         except KeyError:

reframe/frontend/executors/__init__.py

@@ -44,6 +44,9 @@ def __init__(self, check, partition, environ):
         # Incoming dependencies
         self.in_degree = 0
 
+        # Level in the dependency chain
+        self.level = 0
+
     def __iter__(self):
         # Allow unpacking a test case with a single liner:
         #       c, p, e = case

requirements.txt

@@ -1,10 +1,12 @@
+argcomplete==1.12.2
+coverage==5.3
 importlib_metadata==2.0.0
 jsonschema==3.2.0
 pytest==6.2.0
 pytest-forked==1.3.0
 pytest-parallel==0.1.0
-coverage==5.3
+PyYAML==5.3.1
+requests==2.25.1
 setuptools==50.3.0
 wcwidth==0.2.5
-argcomplete==1.12.2
 #+pygelf%pygelf==0.3.6

unittests/test_ci.py

@@ -0,0 +1,32 @@
+# Copyright 2016-2021 Swiss National Supercomputing Centre (CSCS/ETH Zurich)
+# ReFrame Project Developers. See the top-level LICENSE file for details.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+
+import io
+import requests
+
+import reframe.frontend.ci as ci
+import reframe.frontend.dependencies as dependencies
+import reframe.frontend.executors as executors
+from reframe.frontend.loader import RegressionCheckLoader
+
+
+def test_ci_gitlab_pipeline():
+    loader = RegressionCheckLoader([
+        'unittests/resources/checks_unlisted/deps_complex.py'
+    ])
+    cases = dependencies.toposort(
+        dependencies.build_deps(
+            executors.generate_testcases(loader.load_all())
+        )[0]
+    )
+    with io.StringIO() as fp:
+        ci.emit_pipeline(fp, cases)
+        yaml = fp.getvalue()
+
+    response = requests.post('https://gitlab.com/api/v4/ci/lint',
+                             data={'content': {yaml}})
+    assert response.ok
+    assert response.json()['status'] == 'valid'

unittests/test_dependencies.py

@@ -804,6 +804,18 @@ def test_toposort(make_test, exec_ctx):
     cases = dependencies.toposort(deps)
     assert_topological_order(cases, deps)
 
+    # Assert the level assignment
+    cases_by_level = {}
+    for c in cases:
+        cases_by_level.setdefault(c.level, set())
+        cases_by_level[c.level].add(c.check.name)
+
+    assert cases_by_level[0] == {'t0', 't5'}
+    assert cases_by_level[1] == {'t1', 't6', 't7'}
+    assert cases_by_level[2] == {'t2', 't8'}
+    assert cases_by_level[3] == {'t3'}
+    assert cases_by_level[4] == {'t4'}
+
 
 def test_toposort_subgraph(make_test, exec_ctx):
     #
@@ -836,3 +848,12 @@ def test_toposort_subgraph(make_test, exec_ctx):
     )
     cases = dependencies.toposort(partial_deps, is_subgraph=True)
     assert_topological_order(cases, partial_deps)
+
+    # Assert the level assignment
+    cases_by_level = {}
+    for c in cases:
+        cases_by_level.setdefault(c.level, set())
+        cases_by_level[c.level].add(c.check.name)
+
+    assert cases_by_level[1] == {'t3'}
+    assert cases_by_level[2] == {'t4'}