The compose/swarm split on `depends_on:` shape (map form with
`condition:` vs. list form, per `docker stack deploy` constraint)
was being hand-coded as a `{% if DEPLOYMENT_MODE == 'swarm' %}` gate
around every block. Repetitive, easy to forget, and templates that
did remember it had to repeat the same six-line pattern per service.
The new `depends_on` lookup encapsulates the shape switch:
{{ lookup('depends_on', {SVC: 'service_healthy', …}) }} # mapping
{{ lookup('depends_on', [SVC_A, SVC_B]) }} # all default
- Compose -> map form with explicit `condition:` per entry.
- Swarm -> list form (just names; swarm ignores depends_on
ordering semantically but accepts the syntax).
- Mapping `None` value uses the default condition (`service_started`,
matching Docker Compose's behaviour when no condition is given).
- Plain list of names uses the default for every entry.
The output is shaped so the call site reads naturally at the
service-member column:
some_service:
image: …
{{ lookup('depends_on', {DB: 'service_healthy'}) }} # at col 4
volumes: …
Concretely the lookup emits line 1 WITHOUT leading whitespace and
lines 2+ with the `indent` kwarg (default 4) plus the YAML-relative
nested indent. Jinja substitution applies the template's leading
spaces to line 1 only, so the column-4 call placement makes
`depends_on:` land at column 4 and the children at 6 / 8. Lines 2+
carry their own indent because Jinja does not propagate template-side
leading whitespace to continuation lines.
Plugin + tests:
- plugins/lookup/depends_on.py: ~190 lines. Mapping / list / empty
input handling, default_condition kwarg, condition validation
against the closed set `{service_started, service_healthy,
service_completed_successfully}`, DEPLOYMENT_MODE resolution via
templar with `mode=` test-only override, indent kwarg semantics
documented in the module docstring.
- tests/unit/plugins/lookup/test_depends_on.py: 27 cases covering
TestInputNormalisation (mapping / list / empty / typo / single
string rejection / non-string sequence rejection / unsupported
type rejection / arity errors), TestModeBehaviour (compose / swarm
/ unknown-falls-to-compose / missing-DEPLOYMENT_MODE-falls-to-compose
/ mode-kwarg override), TestOutputFormatting (line-1 unindented
exact-string assertion, indent=0 edge case, indent=6 edge case,
insertion-order stability for diff-stable output).
Lint:
- tests/lint/ansible/jinja/test_compose_template_uses_depends_on_lookup.py:
rule key `compose-depends-on-must-use-lookup`. Flags three patterns
in any `*compose*.yml.j2` under `roles/`:
1. literal `depends_on:` keyword line
2. flow-form `depends_on: [a, b]`
3. literal `condition: service_*` line
The pre-existing `lookup('container_depends_on', application_id)`
is intentionally not flagged: its call form contains no literal
`depends_on:` token in source. Scan target broadened to
`name.endswith('.yml.j2') and 'compose' in name` so
`compose.override.yml.j2` and `compose-inits.yml.j2` are covered
alongside `compose.yml.j2` and `*.compose.yml.j2`.
Migration (43 depends_on blocks across 17 templates):
- erpnext (6): configurator + backend + websocket + scheduler +
queue-short + queue-long + frontend chains.
- mailu (8): imap + smtp + oletools + antispam + antivirus + webdav +
fetchmail + webmail.
- zammad (4): rails + 3 worker shapes.
- shopware (4): web + worker + scheduler + opensearch, init-gated.
- jitsi (3): three single-key dependencies on JITSI_PROSODY_CONTAINER.
- kix (3): backend + frontend + proxy.
- bigbluebutton/compose.override.yml.j2 (2): bbb-web + etherpad,
inside the existing BBB_COLLABORA_ENABLED gate.
- moodle (2): nginx + cron, both depending on moodle.
- opentalk (2): application + recorder.
- taiga (2): events + gateway.
- matrix (1): loop-driven via `{% set deps = {} %} +
__setitem__` escape hatch over MATRIX_BRIDGES.
- matomo (1): bootstrap service.
- nextcloud (1): whiteboard sidecar.
- openproject (1): proxy.
- funkwhale (1): front.
- magento (1): nginx.
- flowise (1): postgres + redis.
Pre-existing `lookup('container_depends_on', application_id)` calls
(erpnext, nextcloud, moodle, zammad, taiga, matrix, etc.) are left
untouched -- that lookup auto-detects DB / redis from the application
config and emits its own block; it is the app-aware counterpart to
this structural lookup.
Every call placement repositioned to column 4 (standard
compose-service-member indent) so the new line-1-unindented semantic
renders correctly. Eight templates needed the column-4 reposition
(via a mechanical one-shot script that was deleted after).
`make test` green; new lint + 27 unit tests green; independent
re-grep across all `*compose*.yml.j2` finds zero residual raw
`depends_on:` / `condition:` lines.
Ansible Plugins (plugins/) 🧩
This document is the central reference for plugin types and plugin placement in Infinito.Nexus.
Current Project Layout 🗂️
plugins/
├── action/ # custom action plugins
├── filter/ # custom Jinja2 filters
└── lookup/ # custom lookup plugins
Configured plugin paths in this repository are defined in ansible.cfg:
action_plugins = ./plugins/actionfilter_plugins = ./plugins/filterlookup_plugins = ./plugins/lookup
All Common Ansible Plugin Types 📚
The table below summarizes common Ansible plugin types and their conventional directory names.
| Emoji | Plugin Type | Conventional Directory | Purpose |
|---|---|---|---|
| ⚙️ | action |
action_plugins/ or plugins/action/ |
Wrap/extend module execution behavior at task runtime. |
| 🔐 | become |
become_plugins/ |
Implement privilege escalation methods. |
| 💾 | cache |
cache_plugins/ |
Persist gathered facts and cached data between runs. |
| 📣 | callback |
callback_plugins/ |
React to play/task events (logging, reporting, notifications). |
| 🖧 | cliconf |
cliconf_plugins/ |
Define CLI command transport behavior (mainly network platforms). |
| 🔌 | connection |
connection_plugins/ |
Control how Ansible connects to targets (ssh, local, etc.). |
| 🔍 | filter |
filter_plugins/ or plugins/filter/ |
Add Jinja2 filters for data transformation. |
| 🌐 | httpapi |
httpapi_plugins/ |
API transport layer over HTTP(S), mainly for network devices. |
| 🧭 | inventory |
inventory_plugins/ |
Build dynamic inventories from APIs, services, or files. |
| 👉 | lookup |
lookup_plugins/ or plugins/lookup/ |
Resolve dynamic values during playbook processing. |
| 🛰️ | netconf |
netconf_plugins/ |
NETCONF transport integration for network automation. |
| 🐚 | shell |
shell_plugins/ |
Adjust shell command wrapping/execution behavior. |
| 🧠 | strategy |
strategy_plugins/ |
Customize task scheduling/execution strategy. |
| ✅ | test |
test_plugins/ |
Add Jinja2 tests used in conditions and templates. |
| 📦 | vars |
vars_plugins/ |
Load variables from custom sources. |
Which Plugin Type to Use 🧭
action ⚙️
Use when task execution behavior itself must be changed or wrapped.
Examples:
- centralized retry logic (
uri_retry.py), - argument normalization before module dispatch,
- pre/post task orchestration.
filter 🔍
Use for pure data transformation in Jinja2 expressions.
Examples:
- mapping/normalizing dictionaries,
- deriving computed fields for templates,
- deterministic formatting helpers.
lookup 👉
Use when a value must be dynamically resolved at runtime.
Examples:
- computing IDs from role metadata,
- resolving paths/version data,
- reading structured project data for templates/tasks.
callback 📣
Use to hook into execution events and shape output/reporting.
inventory 🧭
Use when host/group data should come from a dynamic source.
strategy 🧠
Use to alter how tasks are scheduled/executed across hosts.
vars 📦
Use to load variables from custom backends.
connection, become, shell 🔌🔐🐚
Use to customize low-level execution and privilege mechanics.
cache 💾
Use to persist facts/results across runs for performance and consistency.
cliconf, httpapi, netconf 🖧🌐🛰️
Use in network automation contexts requiring protocol-specific transport behavior.
test ✅
Use to add custom Jinja2 test operators for conditional logic.
Best Practices 🧪
- Keep plugin interfaces explicit and stable.
- Keep plugin logic focused; move shared logic to
utils/. - Add unit tests for plugin behavior and integration tests for end-to-end flows.
- Prefer deterministic outputs and avoid hidden global state.
- Document any plugin-specific task arguments in the plugin docstring and README.
References 🔗
- Ansible plugin development: https://docs.ansible.com/ansible/latest/dev_guide/developing_plugins.html
- Ansible plugin index (all types): https://docs.ansible.com/ansible/latest/plugins/plugins.html
- Ansible
ansible-docplugin types:ansible-doc -t ...