The Module Build Service (MBS) for Modularity

The MBS coordinates module builds and is responsible for a number of tasks:

  • Providing an interface for module client-side tooling via which module build submission and build state queries are possible.
  • Verifying the input data (modulemd, RPM SPEC files and others) is available and correct.
  • Preparing the build environment in the supported build systems, such as koji.
  • Scheduling and building of the module components and tracking the build state.
  • Emitting bus messages about all state changes so that other infrastructure services can pick up the work.

Development

For help on setting up a development environment, see docs/CONTRIBUTING.rst.

Client-side API

The orchestrator implements a RESTful interface for module build submission and state querying. Not all REST methods are supported. See below for details.

Module build submission

Module submission is done via posting the modulemd SCM URL.

POST /module-build-service/1/module-builds/
{
    "scmurl": "git://pkgs.fedoraproject.org/modules/foo.git/foo.yaml?#f1d2d2f924e986ac86fdf7b36c94bcdf32beec15
}

The response, in case of a successful submission, would include the task ID.

HTTP 201 Created
{
    id: 42
}

When YAML_SUBMIT_ALLOWED is enabled, it is also possible to submit raw modulemd yaml file by sending multipart/form-data request with input file named as yaml.

Module build state query

Once created, the client can query the current build state by requesting the build task's URL. Querying the BPO service might be preferred, however.

GET /module-build-service/1/module-builds/42

The response, if the task exists, would include various pieces of information about the referenced build task.

HTTP 200 OK
{
    "id": 42,
    "state": "build",
    "tasks": {
        "rpms": {
            "foo": {
                "task_id": 6378,
                "state": 1,
                "state_reason": None,
                "nvr": "foo-1.2.3-1...",
            },
            "bar": {
                "task_id": 6379,
                "state": 0,
                "state_reason": None,
                "nvr": None,
            }

        }
    },
    ...
}

"id" is the ID of the task. "state" refers to the orchestrator module build state and might be one of "init", "wait", "build", "done", "failed" or "ready". "tasks" is a dictionary of information about the individual component builds including their IDs in the backend buildsystem, their state, a reason for their state, and the NVR (if known).

By adding ?verbose=1 to the request, additional detailed information about the module can be obtained.

GET /module-build-service/1/module-builds/42?verbose=1

Listing all module builds

The list of all tracked builds and their states can be obtained by querying the "module-builds" resource. There are a number of configurable GET parameters to change how the module builds are displayed. These parameters are:

  • verbose - Shows the builds with the same amount of detail as querying them individually (i.e. verbose=True). This value defaults to False.
  • page - Specifies which page should be displayed (e.g. page=3). This value defaults to 1.
  • per_page - Specifies how many items per page should be displayed (e.g. per_page=20). This value defaults to 10.

An example of querying the "module-builds" resource without any additional parameters:

GET /module-build-service/1/module-builds/
HTTP 200 OK
{
  "items": [
    {
      "id": 1,
      "state": 3
    },
    {
      "id": 2,
      "state": 3
    },
    {
      "id": 3,
      "state": 3
    },
    {
      "id": 4,
      "state": 4
    },
    {
      "id": 5,
      "state": 4
    },
    {
      "id": 6,
      "state": 4
    },
    {
      "id": 7,
      "state": 4
    },
    {
      "id": 8,
      "state": 4
    },
    {
      "id": 9,
      "state": 4
    },
    {
      "id": 10,
      "state": 1
    }
  ],
  "meta": {
    "first": "https://127.0.0.1:5000/module-build-service/1/module-builds/?per_page=10&page=1",
    "last": "https://127.0.0.1:5000/module-build-service/1/module-builds/?per_page=10&page=3",
    "next": "https://127.0.0.1:5000/module-build-service/1/module-builds/?per_page=10&page=2",
    "page": 1,
    "pages": 3,
    "per_page": 10,
    "total": 30
  }
}

An example of querying the "module-builds" resource with the "verbose", "per_page", and the "page" parameters:

GET /module-build-service/1/module-builds/?verbose=true&per_page=3&page=1
HTTP 200 OK
{
  "items": [
    {
      "id": 1,
      "name": "testmodule",
      "owner": "mprahl",
      "state": 3,
      "tasks": {
        "rpms": {
          "bash": {
            "task_id": 90109464,
            "state": 1,
            ...
          },
          "module-build-macros": {
            "task_id": 90109446,
            "state": 1,
            ...
          }
        }
      },
      "time_completed": "2016-08-22T09:44:11Z",
      "time_modified": "2016-08-22T09:44:11Z",
      "time_submitted": "2016-08-22T09:40:07Z"
    },
    {
      "id": 2,
      "name": "testmodule",
      "owner": "ralph",
      "state": 3,
      "tasks": {
        "rpms": {
          "bash": {
            "task_id": 90109465,
            "state": 1,
            ...
          },
          "module-build-macros": {
            "task_id": 90109450,
            "state": 1,
            ...
          }
        }
      },
      "time_completed": "2016-08-22T09:54:04Z",
      "time_modified": "2016-08-22T09:54:04Z",
      "time_submitted": "2016-08-22T09:48:11Z"
    },
    {
      "id": 3,
      "name": "testmodule",
      "owner": "mprahl",
      "state": 3,
      "tasks": {
        "rpms": {
          "bash": {
            "task_id": 90109497,
            "state": 1,
            ...
          },
          "module-build-macros": {
            "task_id": 90109480,
            "state": 1,
            ...
          }
        }
      },
      "time_completed": "2016-08-22T10:05:08Z",
      "time_modified": "2016-08-22T10:05:08Z",
      "time_submitted": "2016-08-22T09:58:04Z"
    }
  ],
  "meta": {
    "first": "https://127.0.0.1:5000/module-build-service/1/module-builds/?per_page=3&page=1",
    "last": "https://127.0.0.1:5000/module-build-service/1/module-builds/?per_page=3&page=10",
    "next": "https://127.0.0.1:5000/module-build-service/1/module-builds/?per_page=3&page=2",
    "page": 1,
    "pages": 10,
    "per_page": 3,
    "total": 30
  }
}

Filtering module builds

The module-builds can be filtered by a variety of GET parameters. These paramters are:

  • owner - Shows builds submitted by a particular user (e.g. owner=mprahl)
  • state - Shows builds in a particular state (can be the state name or the state ID) (e.g. state=done)
  • submitted_before - Shows builds that were submitted before a particular Zulu ISO 8601 timestamp (e.g. submitted_before=2016-08-23T09:40:07Z)
  • submitted_after - Shows builds that were submitted after a particular Zulu ISO 8601 timestamp (e.g. submitted_after=2016-08-22T09:40:07Z)
  • modified_before - Shows builds that were modified before a particular Zulu ISO 8601 timestamp (e.g. modified_before=2016-08-23T09:40:07Z)
  • modified_after - Shows builds that were modified after a particular Zulu ISO 8601 timestamp (e.g. modified_after=2016-08-22T09:40:07Z)
  • completed_before - Shows builds that were completed before a particular Zulu ISO 8601 timestamp (e.g. completed_before=2016-08-22T09:40:07Z)
  • completed_after - Shows builds that were completed after a particular Zulu ISO 8601 timestamp (e.g. completed_after=2016-08-23T09:40:07Z)

An example of querying the "module-builds" resource with the "state", and the "submitted_before" parameters:

GET /module-build-service/1/module-builds/?state=done&submitted_before=2016-08-23T08:10:07Z
HTTP 200 OK
{
  "items": [
    {
      "id": 1,
      "state": 3
    },
    {
      "id": 2,
      "state": 3
    },
    {
      "id": 3,
      "state": 3
    }
  ],
  "meta": {
    "first": "https://127.0.0.1:5000/module-build-service/1/module-builds/?per_page=10&page=1",
    "last": "https://127.0.0.1:5000/module-build-service/1/module-builds/?per_page=10&page=1",
    "page": 1,
    "pages": 1,
    "per_page": 3,
    "total": 3
  }

HTTP Response Codes

Possible response codes are for various requests include:

  • HTTP 200 OK - The task exists and the query was successful.
  • HTTP 201 Created - The module build task was successfully created.
  • HTTP 400 Bad Request - The client's input isn't a valid request.
  • HTTP 403 Forbidden - The SCM URL is not pointing to a whitelisted SCM server.
  • HTTP 404 Not Found - The requested URL has no handler associated with it or the requested resource doesn't exist.
  • HTTP 409 Conflict - The submitted module's NVR already exists.
  • HTTP 422 Unprocessable Entity - The submitted modulemd file is not valid or the module components cannot be retrieved
  • HTTP 500 Internal Server Error - An unknown error occured.
  • HTTP 501 Not Implemented - The requested URL is valid but the handler isn't implemented yet.
  • HTTP 503 Service Unavailable - The service is down, possibly for maintanance.

Module Build States

You can see the list of possible states with:

from module_build_service.models import BUILD_STATES
print(BUILD_STATES)

Here's a description of what each of them means:

init

This is (obviously) the first state a module build enters.

When a user first submits a module build, it enters this state. We parse the modulemd file, learn the NVR, and create a record for the module build.

Then, we validate that the components are available, and that we can fetch them. If this is all good, then we set the build to the 'wait' state. If anything goes wrong, we jump immediately to the 'failed' state.

wait

Here, the scheduler picks up tasks in wait and switches to build immediately. Eventually, we'll add throttling logic here so we don't submit too many builds for the build system to handle.

build

The scheduler works on builds in this state. We prepare the buildroot, submit builds for all the components, and wait for the results to come back.

done

Once all components have succeeded, we set the top-level module build to 'done'.

failed

If any of the component builds fail, then we set the top-level module build to 'failed' also.

ready

This is a state to be set when a module is ready to be part of a larger compose. perhaps it is set by an external service that knows about the Grand Plan.

Bus messages

Message Topic

The suffix for message topics concerning changes in module state is module.state.change. Currently, it is expected that these messages are sent from koji or module_build_service_daemon, i.e. the topic is prefixed with *.buildsys. or *.module_build_service., respectively.

Message Body

The message body is a dictionary with these fields:

state

This is the current state of the module, corresponding with the states described above in Module Build States.

name, version, release

Name, version and release of the module.

scmurl

Specifies the exact repository state from which a module is built.

E.g. "scmurl": "git://pkgs.stg.fedoraproject.org/modules/testmodule.git?#020ea37251df5019fde9e7899d2f7d7a987dfbf5"

topdir

The toplevel directory containing the trees for each architecture of a module. This field is only present when a module finished building, i.e. with the states 'done' or 'ready'.

Configuration

MBS configures itself according to the environment where it runs + according to the following rules (all of them are evaluated from top to bottom):

  • DevConfiguration is the initial configuration chosen.

  • If configuration file is found within its final installation location, ProdConfiguration is assumed.

  • If Flask app running within mod_wsgi is detected, ProdConfiguration is assumed.

  • If environment variables determining configuration file/section are found, they are used for configuration. Following environment variables are recognized:

    • MBS_CONFIG_FILE: Overrides default configuration file location, typically /etc/module-build-service/config.py.
    • MBS_CONFIG_SECTION: Overrides configuration section.

    It is possible to set these values in httpd using SetEnv, anywhere in /etc/profile.d/ etc.

  • If test-runtime environment is detected, TestConfiguration is used, otherwise...

  • if MODULE_BUILD_SERVICE_DEVELOPER_ENV is set to some reasonable value, DevConfiguration is forced and config.py is used directly from the MBS's develop instance. For more information see docs/CONTRIBUTING.rst.