Replace multi-role checks with action plugin

This approach should make it easier to add new checks without having to
write lots of YAML and doing things against Ansible (e.g.
ignore_errors).

A single action plugin determines what checks to run per each host,
including arguments to the check. A check is implemented as a class with
a run method, with the same signature as an action plugin and module,
and is normally backed by a regular Ansible module.

Each check is implemented as a separate Python file. This allows whoever
adds a new check to focus solely in a single Python module, and
potentially an Ansible module within library/ too.

All checks are automatically loaded, and only active checks that are
requested by the playbook get executed.

2 files changed, 190 insertions, 0 deletions

diff --git a/roles/openshift_health_checker/library/aos_version.py b/roles/openshift_health_checker/library/aos_version.py
new file mode 100755
index 000000000..37c8b483c
--- /dev/null
+++ b/roles/openshift_health_checker/library/aos_version.py
@@ -0,0 +1,85 @@
+#!/usr/bin/python
+# vim: expandtab:tabstop=4:shiftwidth=4
+'''
+Ansible module for determining if multiple versions of an OpenShift package are
+available, and if the version requested is available down to the given
+precision.
+
+Multiple versions available suggest that multiple repos are enabled for the
+different versions, which may cause installation problems.
+'''
+
+import yum  # pylint: disable=import-error
+
+from ansible.module_utils.basic import AnsibleModule
+
+
+def main():  # pylint: disable=missing-docstring
+    module = AnsibleModule(
+        argument_spec=dict(
+            version=dict(required=True)
+        ),
+        supports_check_mode=True
+    )
+
+    def bail(error):  # pylint: disable=missing-docstring
+        module.fail_json(msg=error)
+
+    yb = yum.YumBase()  # pylint: disable=invalid-name
+
+    # search for package versions available for aos pkgs
+    expected_pkgs = [
+        'atomic-openshift',
+        'atomic-openshift-master',
+        'atomic-openshift-node',
+    ]
+    try:
+        pkgs = yb.pkgSack.returnPackages(patterns=expected_pkgs)
+    except yum.Errors.PackageSackError as e:  # pylint: disable=invalid-name
+        # you only hit this if *none* of the packages are available
+        bail('Unable to find any atomic-openshift packages. \nCheck your subscription and repo settings. \n%s' % e)
+
+    # determine what level of precision we're expecting for the version
+    expected_version = module.params['version']
+    if expected_version.startswith('v'):  # v3.3 => 3.3
+        expected_version = expected_version[1:]
+    num_dots = expected_version.count('.')
+
+    pkgs_by_name_version = {}
+    pkgs_precise_version_found = {}
+    for pkg in pkgs:
+        # get expected version precision
+        match_version = '.'.join(pkg.version.split('.')[:num_dots + 1])
+        if match_version == expected_version:
+            pkgs_precise_version_found[pkg.name] = True
+        # get x.y version precision
+        minor_version = '.'.join(pkg.version.split('.')[:2])
+        if pkg.name not in pkgs_by_name_version:
+            pkgs_by_name_version[pkg.name] = {}
+        pkgs_by_name_version[pkg.name][minor_version] = True
+
+    # see if any packages couldn't be found at requested version
+    # see if any packages are available in more than one minor version
+    not_found = []
+    multi_found = []
+    for name in expected_pkgs:
+        if name not in pkgs_precise_version_found:
+            not_found.append(name)
+        if name in pkgs_by_name_version and len(pkgs_by_name_version[name]) > 1:
+            multi_found.append(name)
+    if not_found:
+        msg = 'Not all of the required packages are available at requested version %s:\n' % expected_version
+        for name in not_found:
+            msg += '  %s\n' % name
+        bail(msg + 'Please check your subscriptions and enabled repositories.')
+    if multi_found:
+        msg = 'Multiple minor versions of these packages are available\n'
+        for name in multi_found:
+            msg += '  %s\n' % name
+        bail(msg + "There should only be one OpenShift version's repository enabled at a time.")
+
+    module.exit_json(changed=False)
+
+
+if __name__ == '__main__':
+    main()
diff --git a/roles/openshift_health_checker/library/check_yum_update.py b/roles/openshift_health_checker/library/check_yum_update.py
new file mode 100755
index 000000000..9bc14fd47
--- /dev/null
+++ b/roles/openshift_health_checker/library/check_yum_update.py
@@ -0,0 +1,105 @@
+#!/usr/bin/python
+# vim: expandtab:tabstop=4:shiftwidth=4
+'''
+Ansible module to test whether a yum update or install will succeed,
+without actually performing it or running yum.
+parameters:
+  packages: (optional) A list of package names to install or update.
+            If omitted, all installed RPMs are considered for updates.
+'''
+
+import sys
+
+import yum  # pylint: disable=import-error
+
+from ansible.module_utils.basic import AnsibleModule
+
+
+def main():  # pylint: disable=missing-docstring,too-many-branches
+    module = AnsibleModule(
+        argument_spec=dict(
+            packages=dict(type='list', default=[])
+        ),
+        supports_check_mode=True
+    )
+
+    def bail(error):  # pylint: disable=missing-docstring
+        module.fail_json(msg=error)
+
+    yb = yum.YumBase()  # pylint: disable=invalid-name
+    # determine if the existing yum configuration is valid
+    try:
+        yb.repos.populateSack(mdtype='metadata', cacheonly=1)
+    # for error of type:
+    #   1. can't reach the repo URL(s)
+    except yum.Errors.NoMoreMirrorsRepoError as e:  # pylint: disable=invalid-name
+        bail('Error getting data from at least one yum repository: %s' % e)
+    #   2. invalid repo definition
+    except yum.Errors.RepoError as e:  # pylint: disable=invalid-name
+        bail('Error with yum repository configuration: %s' % e)
+    #   3. other/unknown
+    #    * just report the problem verbatim
+    except:  # pylint: disable=bare-except; # noqa
+        bail('Unexpected error with yum repository: %s' % sys.exc_info()[1])
+
+    packages = module.params['packages']
+    no_such_pkg = []
+    for pkg in packages:
+        try:
+            yb.install(name=pkg)
+        except yum.Errors.InstallError as e:  # pylint: disable=invalid-name
+            no_such_pkg.append(pkg)
+        except:  # pylint: disable=bare-except; # noqa
+            bail('Unexpected error with yum install/update: %s' %
+                 sys.exc_info()[1])
+    if not packages:
+        # no packages requested means test a yum update of everything
+        yb.update()
+    elif no_such_pkg:
+        # wanted specific packages to install but some aren't available
+        user_msg = 'Cannot install all of the necessary packages. Unavailable:\n'
+        for pkg in no_such_pkg:
+            user_msg += '  %s\n' % pkg
+        user_msg += 'You may need to enable one or more yum repositories to make this content available.'
+        bail(user_msg)
+
+    try:
+        txn_result, txn_msgs = yb.buildTransaction()
+    except:  # pylint: disable=bare-except; # noqa
+        bail('Unexpected error during dependency resolution for yum update: \n %s' %
+             sys.exc_info()[1])
+
+    # find out if there are any errors with the update/install
+    if txn_result == 0:  # 'normal exit' meaning there's nothing to install/update
+        pass
+    elif txn_result == 1:  # error with transaction
+        user_msg = 'Could not perform a yum update.\n'
+        if len(txn_msgs) > 0:
+            user_msg += 'Errors from dependency resolution:\n'
+            for msg in txn_msgs:
+                user_msg += '  %s\n' % msg
+            user_msg += 'You should resolve these issues before proceeding with an install.\n'
+            user_msg += 'You may need to remove or downgrade packages or enable/disable yum repositories.'
+        bail(user_msg)
+    # TODO: it would be nice depending on the problem:
+    #   1. dependency for update not found
+    #    * construct the dependency tree
+    #    * find the installed package(s) that required the missing dep
+    #    * determine if any of these packages matter to openshift
+    #    * build helpful error output
+    #   2. conflicts among packages in available content
+    #    * analyze dependency tree and build helpful error output
+    #   3. other/unknown
+    #    * report the problem verbatim
+    #    * add to this list as we come across problems we can clearly diagnose
+    elif txn_result == 2:  # everything resolved fine
+        pass
+    else:
+        bail('Unknown error(s) from dependency resolution. Exit Code: %d:\n%s' %
+             (txn_result, txn_msgs))
+
+    module.exit_json(changed=False)
+
+
+if __name__ == '__main__':
+    main()