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odpm plugins and extensions (4.4+)

AI-translated from Russian.

odpm 4.4+ adds a host extension API: prepare steps, compose fragments, and lifecycle hooks. Plugins do not get direct access to mutable Config — only frozen ExtensionHostContext.

Extension API version (4.5+)

Stable API: EXTENSION_API_VERSION = "1.0" (dev_project/extensions/api.py). Breaking changes to pluggy protocols or manifest hooks require a major API bump. Policy: ADR-004.

Three ways to extend a project

Mechanism Declared in When it runs
Manifest services odpm.json v2 → services Prepare compose.fragments; plan compose.fragment.<name>
Manifest hooks odpm.json v2 → hooks post_clone after git materialize; post_prepare after prepare; pre_up before compose up
Python entry points package pyproject.toml Pluggy: odpm.prepare_steps, odpm.hooks
Project-local plugins .odpm/plugins/*.py or extensions.local Loaded at bootstrap (sandboxed to project dir)

v2 field details: odpm.json. ADR: adr-001-extensions-and-manifest-v2.md.

Declarative service (Mailpit)

Test SMTP with web UI on port 8025. Add to nested manifest v2:

{
  "manifest_schema": 2,
  "requires_odpm": "4.4.3",
  "services": {
    "mailpit": {
      "image": "axllent/mailpit",
      "restart": "unless-stopped",
      "ports": ["8025:8025", "1025:1025"]
    }
  }
}

Same spec in code: dev_project.extensions.reference.mailpit.MAILPIT_SERVICE_SPEC.

After odpm up the service appears in generated docker-compose.yml ({COMPOSE_SERVICE_FRAGMENTS} block). Materialize artifacts: .odpm/compose/fragments/mailpit.yml (gitignored).

Lifecycle hooks in manifest

"hooks": {
  "post_clone": [
    ["./scripts/after-clone.sh"]
  ],
  "post_prepare": [
    ["./scripts/notify.sh", "prepare-done"],
    "mycompany.odpm.hooks.warmup"
  ],
  "pre_up": [
    ["docker", "network", "create", "odpm-dev", "||", "true"]
  ]
}

Each element is either argv (string array, runs in project_dir) or a plugin id (string) for the pluggy hook runner.

Order per ADR-004:

  1. Git materialize
  2. hooks.post_clone (when configured)
  3. All prepare steps (built-in + odpm.prepare_steps + local plugins), sorted by order
  4. hooks.post_prepare
  5. Runtime: debug profile, IDE, database drift
  6. hooks.pre_up
  7. docker compose up

odpm plan shows hooks.* and compose.fragment.<service> steps when configured.

Prepare step order field

Lower order runs earlier among extension steps (built-in order is fixed in the registry). Conflicting id with a built-in step → ValueError on registration.

Shell hook failure → PipelineError with the command exit code.

Python plugin: compose fragment

# my_odpm_mailpit/__init__.py
from dev_project.extensions import ExtensionHostContext, register_compose_fragment
from dev_project.extensions.reference.mailpit import MAILPIT_SERVICE_SPEC

class MailpitFragment:
    name = "mailpit"

    def compose_services(self, ctx: ExtensionHostContext) -> dict:
        return {"mailpit": dict(MAILPIT_SERVICE_SPEC)}

def _register():
    register_compose_fragment("mailpit", MailpitFragment())

Register on package import or via entry point (see below).

Python plugin: prepare step

[project.entry-points."odpm.prepare_steps"]
my_step = "my_odpm_plugin.steps:plugin_factory"

from dataclasses import dataclass
from dev_project.prepare.helpers import make_plan_step
from dev_project.prepare.types import PrepareContext

@dataclass(frozen=True)
class MyPrepareStep:
    id: str = "mycompany.custom.step"
    description: str = "Custom prepare work"
    order: int = 500

    def evaluate(self, ctx: PrepareContext):
        return make_plan_step(self.id, self.description, "run", True, "always run")

    def execute(self, ctx: PrepareContext) -> None:
        ...

def plugin_factory():
    return MyPrepareStep()

evaluate must be side-effect free — odpm plan calls only evaluate.

Python plugin: lifecycle hook runner

[project.entry-points."odpm.hooks"]
warmup = "my_odpm_plugin.hooks:WarmupRunner"

class WarmupRunner:
    name = "mycompany.odpm.hooks.warmup"

    def run_post_clone(self, ctx) -> None:
        ...

    def run_post_prepare(self, ctx) -> None:
        ...

    def run_pre_up(self, ctx) -> None:
        ...

Id in manifest ("mycompany.odpm.hooks.warmup") must match runner name.

Example package pyproject.toml

[project]
name = "odpm-services-mailpit"
version = "0.1.0"
dependencies = ["odpm>=4.4"]

[project.entry-points."odpm.hooks"]
# optional lifecycle runners

[project.entry-points."odpm.prepare_steps"]
# optional prepare steps

Install the package in the host venv (pip install -e .) next to odpm.

Project-local plugins (4.5+)

Without a separate pip package, place modules under .odpm/plugins/ in the project (this directory only; no .. in module names). Optional allow-list in manifest v2:

"extensions": {
  "local": ["mailpit_local"]
}

Loads project_dir/.odpm/plugins/mailpit_local.py. Example fixture: tests/fixtures/sample_plugin/.

Cookbook (minimal plugin)

  1. Manifest v2 services.mailpit or register_compose_fragment in Python.
  2. Prepare step with side-effect-free evaluate + execute for file writes.
  3. Hook runner with name matching the id in hooks.post_prepare.
  4. pip install -e . or .odpm/plugins/my_plugin.py.
  5. Run odpm plan — verify compose.fragment.*, hooks.*, and extension prepare steps.

Template pyproject.toml: tests/fixtures/sample_plugin/pyproject.toml.

Limitations

  • Container-side ContainerConfig stays stdlib-only (no new PyPI deps in the image).
  • Compose YAML is generated by the host engine dev_project/yaml/ (ruamel.yaml); YAML anchors/merge aliases are not supported.
  • Name conflict: plugin compose fragment overwrites a same-named service from manifest.

See also