adhesive 0.7.2

adhesive

A CI/CD system build around BPMN and Python. Basically a micro BPMN runner with python step implementations targeted for builds. Able to run in the terminal.

Installation

pip install adhesive

Getting Started

Simple Builds

To create a basic build you just create a file in your project named _adhesive.py. In it you then declare some tasks. For example:

import adhesive

@adhesive.task("Checkout Code")
def checkout_code(context):
    adhesive.scm.checkout(context.workspace)

@adhesive.task("Run Build")
def run_build(context):
    context.workspace.run("mvn clean install")

adhesive.build()

Since no process was defined, adhesive takes the defined tasks, stitches them in order, and has a process defined as <start> -> Checkout Code -> Run Build -> <end>.

To run it simply call adhesive in the terminal:

adhesive

This is the equivalent of Jenkins stages. But we can do better:

Programmatic Builds

In order to use the full programmatic functionalities that adhesive offers, you are able to stitch your BPM process manually. You have sub processes, branching and looping available:

import adhesive
import uuid

@adhesive.task("Run in parallel")
def context_to_run(context):
    if not context.data.executions:
        context.data.executions = set()

    context.data.executions.add(str(uuid.uuid4()))

data = adhesive.process_start()\
    .branch_start()\
        .sub_process_start() \
            .task("Run in parallel",
                  loop="context.data.items") \
        .sub_process_end()\
    .branch_end() \
    .branch_start() \
        .sub_process_start() \
            .task("Run in parallel",
                  loop="context.data.items") \
        .sub_process_end() \
    .branch_end() \
    .process_end()\
    .build(initial_data={"items": [1, 2, 3, 4, 5]})

assert len(data.executions) == 10

Here you see the full BPMN power starting to unfold. We create a process that branches out, creates sub processes (sub processes can be looped as a single unit). Loops are creating execution tokens that also run in parallel in the same pool.

Note that you can pass initial_data into the process, and you can also get the context.data from the last execution token.

BPMN Process

Last but not least, adhesive reads BPMN files, and builds the process graph from them. This is particularly good if the process is complex and has a lot of dependencies:

Image Description

The build of adhesive is modeled as a BPMN process itself, so we load it from the file directly using: adhesive.build_bpmn("adhesive-self.bpmn")

import adhesive

@adhesive.task("Read Parameters")
def read_parameters(context) -> None:
    context.data.run_mypy = False
    context.data.test_integration = True

@adhesive.task(r"^Ensure Tooling:\s+(.+)$")
def gbs_ensure_tooling(context, tool_name) -> None:
    ge_tooling.ensure_tooling(context, tool_name)

# ...

adhesive.build_bpmn("adhesive-self.bpmn")

As you see steps are parametrizable, and use the data from the task name into the step definition.

Defining BPMN Tasks

For example here, we define an implementation of tasks:

@adhesive.task(r"^Ensure Tooling:\s+(.+)$")
def gbs_ensure_tooling(context, tool_name) -> None:
    # ...

Or a user task (interactive form):

@adhesive.usertask('Publish to PyPI\?')
def publish_to_pypi_confirm(context, ui):
    ui.add_checkbox_group(
        "publish",
        title="Publish",
        values=(
            ("nexus", "Publish to Nexus"),
            ("pypitest", "Publish to PyPI Test"),
            ("pypi", "Publish to PyPI"),
        ),
        value=("pypitest", "pypi")
    )

Don’t forget, the @adhesive.task and @adhesive.usertask are just defining mappings for implementations of the task names available in the process, unless calling the adhesive.build() that creates a linear process out of these tasks.

As you notice, there’s always a first parameter named context. The context parameter contains the following information:

1. task - the Task in the graph that’s currently matched against this execution.

2. task_name - The resolved name, with the variables interpolated. Matching is attempted after the name is resolved.

3. data - Data that the current execution token contains. This data is always cloned across executions, and sets and dicts are automatically merged if multiple execution tokens are merged. So you have a modifiable copy of the data that you’re allowed to change, and is propagated into the following execution tokens.

4. loop - if the current task is in a loop, the entry contains its index, and a key and value. Note that loop execution happens in parallel since these are simple execution tokens.

5. workspace - a way to interact with a system, and execute commands, create files, etc.

adhesive runs all the tasks on a parallel process pool for better performance. This happens automatically.

The tasks perform the actual work for the build. But in order to have that, we need to be able to execute commands, and create files. For that we have the workspace.

Connections

Tasks are connected to each other with connections. In some cases, connections can have conditions. Conditions are expressions that when evaluated to True will allow the token to pass the connection. In the connection there is access to the task, task_name, data, loop and context, as well as the variables defined in the context.data.

So if in a task there is defined a data field such as:

@adhesive.task('prepare data')
def prepare_data(context):
    context.data.navigation_direction = "forward"

The navigation_direction can be validated in the condition with any of the following:

• context.data.navigation_direction == "forward"

• data.navigation_direction == "forward"

• navigation_direction == "forward"

Workspace

Workspaces are just a way of interacting with a system, running commands, and writing/reading files. Currently only LocalLinuxWorkspace and DockerWorkspace are implemented.

When starting adhesive allocates a default workspace folder in the configured temp location (implicitly /tmp/adhesive). The Workspace API is an API that allows you to run commands, and create files, taking care of redirecting outputs, and even escaping the commands to be able to easily run them inside docker containers.

Note that implicitly calling context.workspace.run(...) will run the command on the host where adhesive is running.

To create a docker workspace that runs inside a container with the tooling you just need to:

from adhesive.workspace import docker

Then to spin up a container that has the current folder mounted in, where you’re able to execute commands inside the container you just need to:

@adhesive.task("Test")
def gbs_test_linux(context) -> None:
    image_name = 'some-custom-python'

    with docker.inside(context.workspace, image_name) as w:
        w.run("python -m pytest -n 4")

This creates a workspace from our current context workspace, where we simply execute what we want, using the run() method. If we’re interested in the program output we simply do a run with a capture_stdout that returns the output as a string.

Here’s the full API for it:

class Workspace(ABC):
    """
    A workspace is a place where work can be done. That means a writable
    folder is being allocated, that might be cleaned up at the end of the
    execution.
    """

    @abstractmethod
    def write_file(
            self,
            file_name: str,
            content: str) -> None:
        pass

    @abstractmethod
    def run(self,
            command: str,
            capture_stdout: bool = False) -> Union[str, None]:
        """
        Run a new command in the current workspace.

        :param capture_stdout:
        :param command:
        :return:
        """
        pass

    @abstractmethod
    def rm(self, path: Optional[str]=None) -> None:
        """
        Recursively remove the file or folder given as path. If no path is sent,
        the whole workspace will be cleared.

        :param path:
        :return:
        """
        pass

    @abstractmethod
    def mkdir(self, path: str=None) -> None:
        """
        Create a folder, including all its needed parents.

        :param path:
        :return:
        """
        pass

    @abstractmethod
    def copy_to_agent(self,
                      from_path: str,
                      to_path: str) -> None:
        """
        Copy the files to the agent from the current disk.
        :param from_path:
        :param to_path:
        :return:
        """
        pass

    @abstractmethod
    def copy_from_agent(self,
                        from_path: str,
                        to_path: str) -> None:
        """
        Copy the files from the agent to the current disk.
        :param from_path:
        :param to_path:
        :return:
        """
        pass

    @contextmanager
    def temp_folder(self):
        """
        Create a temporary folder in the current `pwd` that will be deleted
        when the `with` block ends.

        :return:
        """
        pass

    @contextmanager
    def chdir(self, target_folder: str):
        """
        Temporarily change a folder, that will go back to the original `pwd`
        when the `with` block ends. To change the folder for the workspace
        permanently, simply assing the `pwd`.
        :param target_folder:
        :return:
        """
        pass

User Tasks

In order to create user interactions, you have user tasks. These define form elements that are populated in the context.data, and available in subsequent tasks.

When a user task is encountered in the process flow, the user is prompted to fill in the parameters. Note that the other started tasks continue running, proceeding forward with the build.

The name used in the method call defines the name of the variable that’s in the context.data.

For example in here we define a checkbox group that allows us to pick where to publish the package:

@adhesive.usertask("Read User Data")
def read_user_data(context, ui) -> None:
    ui.add_input_text("user",
            title="Login",
            value="root")
    ui.add_input_password("password",
            title="Password")
    ui.add_checkbox_group("roles",
            title="Roles",
            value=["cyborg"],
            values=["admin", "cyborg", "anonymous"])
    ui.add_radio_group("disabled",  # title is optional
            values=["yes", "no"],
            value="no")
    ui.add_combobox("machine",
            title="Machine",
            values=(("any", "<any>"),
                    ("win", "Windows"),
                    ("lin", "Linux")))

This will prompt the user with this form:

form

This data is also available for edge conditions, so in the BPMN modeler we can define a condition such as "pypi" in context.data.roles, or since data is also available in the edge scope: "pypi" in data.roles.

The other option is simply reading what the user has selected in a following task:

@adhesive.task("Register User")
def publish_items(context):
    for role in context.data.roles:
        # ...

User tasks support the following API, available on the ui parameter, the parameter after the context:

class UiBuilderApi(ABC):
    def add_input_text(self,
                       name: str,
                       title: Optional[str] = None,
                       value: str = '') -> None:

    def add_input_password(self,
                           name: str,
                           title: Optional[str] = None,
                           value: str = '') -> None:

    def add_combobox(self,
                     name: str,
                     title: Optional[str] = None,
                     value: Optional[str]=None,
                     values: Optional[Iterable[Union[Tuple[str, str], str]]]=None) -> None:

    def add_checkbox_group(
            self,
            name: str,
            title: Optional[str]=None,
            value: Optional[Iterable[str]]=None,
            values: Optional[Iterable[Union[Tuple[str, str], str]]]=None) -> None:

    def add_radio_group(self,
                        name: str,
                        title: Optional[str]=None,
                        value: Optional[str]=None,
                        values: Optional[List[Any]]=None) -> None:

    def add_default_button(self,
                           name: str,
                           title: Optional[str] = None,
                           value: Optional[Any] = True) -> None:

Custom Buttons

In order to allow navigation inside the process, the add_default_button API exists to permit creation of buttons. Implicitly a single button with an OK label is added to the User Task, that when pressed fills the context.data in the outgoing execution token.

With add_default_button we create custom buttons such as Back and Forward, or whatever we need in our process. Unlike the default OK button, when these are called, they also set in the context.data the value that’s assigned to them. This value we use then further in a Gateway, or simple as a condition on the outgoing edges.

The title is optional, and only if missing it’s build either from the name if all the buttons in the form have unique names, since they assign a different variable in the context.data, or from the value if they have overlapping names.

Secrets

Secrets are files that contain sensitive information are not checked in the project. In order to make them available to the build, we need to define them in either ~/.adhesive/secrets/SECRET_NAME or in the current folder as .adhesive/secrets/SECRET_NAME.

In order to make them available, we just use the secret function that creates the file in the current workspace and deletes it when exiting. For example here’s how we’re doing the actual publish, creating the secret inside a docker container:

@adhesive.task('^PyPI publish to (.+?)$')
def publish_to_pypi(context, registry):
    with docker.inside(context.workspace, context.data.gbs_build_image_name) as w:
        with secret(w, "PYPIRC_RELEASE_FILE", "/germanium/.pypirc"):
            w.run(f"python setup.py bdist_wheel upload -r {registry}")

Note the docker.inside that creates a different workspace.

Configuration

Adhesive supports configuration via its config files, or environment variables. The values are read in the following order:

1. environment variables: ADHESIVE_XYZ, then

2. values that are in the project config yml file: .adhesive/config.yml, then

3. values configured in the global config yml file: $HOME/.adhesive/config.yml.

Currently the following values are defined for configuration:

temp_folder

default value /tmp/adhesive, environment var: ADHESIVE_TEMP_FOLDER.

Is where all the build files will be stored.

plugins

default value [], environment var: ADHESIVE_PLUGINS_LIST.

This contains a list of folders, that will be added to the sys.path. So to create a reusable plugin that will be reused by multiple builds, you need to simply create a folder with python files, then point to it in the ~/.adhesive/config.yml:

plugins:
- /path/to/folder

Then in the python path you can simply do regular imports.

color

default value True, environment var: ADHESIVE_COLOR.

Marks if the logging should use ANSI colors in the terminal. Implicitly this is true, but if log parsing is needed, it can make sense to have it false.

log_level

default_value info, environment var: ADHESIVE_LOG_LEVEL.

How verbose should the logging be on the terminal. Possible values are trace, debug, info, warning, error and critical.

pool_size

default value is empty, environment var: ADHESIVE_POOL_SIZE.

Sets the number of workers that adhesive will use. Defaults to the number of CPUs if unset.

stdout

default value is empty, environment var: ADHESIVE_STDOUT.

Implicitly for each task, the log is redirected in a different file, and only shown if the task failed. The redirection can be disabled.

parallel_processing

default value is thread, environment var: ADHESIVE_PARALLEL_PROCESSING.

Implicitly tasks are scaled using multiple threads in order to alleviate waits for I/O. This is useful for times when remote ssh workspaces are defined in the lanes, so the same connection can be reused for multiple tasks.

This value can be set to process, in case the tasks are CPU intensive. This has the drawback of recreating the connections on workspaces’ each task execution.

Hacking Adhesive

Adhesive builds with itself. In order to do that, you need to checkout the https://github.com/germaniumhq/adhesive-lib shared plugin, and configure your local config to use it:

plugins:
- /path/to/adhesive-lib

Then simply run the build:

adhesive