reach_commons
Reach's shared Python utility library — SMS encoding, phone validation, structured logging, persistence wrappers (Mongo, DynamoDB, S3, SQS, Firehose, KMS), Redis rate-limiting, and HTTP clients for internal Reach services (event-processor, callback-processor, reach-ops, reach-data-bridge), plus third-party integrations (HubSpot, Outscraper).
Distributed as the reach-commons wheel on
PyPI. Source of truth: https://gitlab.com/reach.ai/reach-commons.
Install
pip install reach-commons
Pin a version in requirements.txt / pyproject.toml like any other dep. Releases
are published from main by GitLab CI (see Release flow).
Quick example
from reach_commons.sms_smart_encoding import MessageSmartEncoding
msg = MessageSmartEncoding("Hello world!")
print(msg.encoding, msg.length, msg.segments) # GSM-7 12 1
Repo layout
reach_commons/
├── app_logging/ structured logger, http logger, deprecation tracker
├── clients/ thin HTTP wrappers for Reach internal services + 3rd-party APIs
│ ├── _auth.py shared Bearer-header helper (reads lambda_function_api_key)
│ ├── callback_processor.py
│ ├── event_processor.py
│ ├── hubspot.py
│ ├── nightly_lambda.py
│ ├── outscraper.py
│ ├── reach_data_bridge.py
│ └── reach_ops_api.py
├── credentials.py one named accessor per Parameter Store credential
├── mongo/ MongoDB customer persistence (sync + async)
├── reach_aws/ boto3 wrappers (dynamodb, s3, sqs, firehose, kms, rate limiter)
├── reach_base_model.py
├── redis_manager.py
├── sms_smart_encoding.py GSM-7 / UCS-2 detection + segment math
├── utils.py
└── validations.py phone-number validator (Twilio Lookups)
tests/ pytest, every suite uses @pytest.mark.parametrize
Security model
Starting with version 0.18.57, the wheel published to PyPI contains zero
credentials. Every secret consumed by reach_commons is fetched at runtime from
AWS Systems Manager Parameter Store (SecureString), sourced from
/terraform/shared-config.tf (shared_ssm_secure).
Why this matters: reach_commons is published to public PyPI. Anyone can
pip download reach-commons. The wheel is intended to be safe in that posture
— if it gets shared outside Reach (forked, cloned by an external dev, included
in a third-party tool), no Reach credentials travel with it.
Access control lives in IAM: a consumer Lambda can only read the secrets
its execution role grants ssm:GetParameter on. No env vars, no hardcoded
fallbacks, no setattr side-channels.
Credential accessors
Every credential kept in Parameter Store has one named accessor in
reach_commons/credentials.py, and that module is the only place its path is written.
A value shared by several services is one parameter named after its vendor
(/stripe/{env}/secret-key), never after a consumer, so rotating it is one write.
from reach_commons import credentials
credentials.preload(credentials.stripe_secret_key, credentials.sendgrid_api_key)
def handler(event, context):
stripe.api_key = credentials.stripe_secret_key()
preload(...) at module import resolves the credentials during the cold start, so a
missing IAM grant or parameter raises there instead of on the first request. Handlers
then call the accessor itself, which reads the in-process cache and picks up a rotation
within the TTL. Do not copy a value into a module-level constant: that pins it for the
life of the container.
{env} resolves to staging / prod from the ENV Lambda env var (defaults to
Staging). The commons clients read theirs the same way: _auth uses
reach_internal_api_key, CommonsPhoneNumberValidation the Twilio pair, and
OutscraperClient the Outscraper token and webhook URL.
Required consumer Lambda IAM
Grant ssm:GetParameter on each exact parameter the consumer reads, in its own
environment only. Never a prefix and never GetParametersByPath: a by-path read is how
one service once pulled the other environment's secrets into its state.
statement {
sid = "ReadOwnCredentials"
effect = "Allow"
actions = ["ssm:GetParameter"]
resources = [
"arn:aws:ssm:us-east-1:383836045505:parameter/api-keys/${lower(var.tag)}/lambda-function-api-key",
"arn:aws:ssm:us-east-1:383836045505:parameter/stripe/${lower(var.tag)}/secret-key",
]
}
The parameters use the default alias/aws/ssm key. /terraform/ssm-credential-reads.tf
is the reference for the lambda roles in that repo.
Caching and rotation
reach_commons._ssm caches each SSM value in-memory with a 1-hour TTL per
process. Cold start = 1 GetParameter per credential (~50ms each); warm
container reuses the cached value until expiry.
After 1h, a rotation in SSM is picked up automatically on the next call — no redeploy needed. To force an immediate refresh, redeploy / recycle the Lambda containers.
Test / local override
Each affected client accepts explicit kwargs so tests and local tooling can bypass SSM entirely:
CommonsPhoneNumberValidation(account_sid="ACtest", auth_token="...")
OutscraperClient(token="...", webhook_url="https://...")
reach_api_bearer_header() has no kwarg path — tests should
monkeypatch.setattr(reach_commons.clients._auth, "get_secure", lambda p: "...").
Local development
poetry install # runtime + dev deps into .venv
poetry run pre-commit install # one-time: enables commit/push hooks
poetry run pytest # full suite
poetry run ruff check reach_commons tests
poetry run ruff format --check reach_commons tests
poetry run pyright reach_commons tests
Python floor: ^3.8. CI runs on python:3.13-slim.
Pre-commit hooks
.pre-commit-config.yaml installs three layers:
- On commit (fast): trailing-whitespace, end-of-file-fixer, check-yaml, check-toml, check-merge-conflict, check-added-large-files, ruff (lint + autofix), ruff-format.
- On push (slower): pyright with the runtime deps as
additional_dependencies.
Pyright runs only on push so day-to-day commits stay fast.
Release flow
GitLab CI publishes to PyPI automatically. Workflow:
- Open an MR against
main. - CI runs
lint+typecheck+teston every push (verify stage). - Merge to
main. - The
publish_pypijob compares theversioninpyproject.tomlagainst the latest version on PyPI:- If
pyproject.toml > PyPI: builds the wheel + sdist and uploads viapoetry publish. - Otherwise: logs
::: skip — local X <= PyPI Yand exits cleanly.
- If
So a release = bump version in pyproject.toml, merge to main. Done.
Pipeline shape
verify ──► lint (ruff check + ruff format --check)
──► typecheck (pyright)
──► test (pytest)
publish ──► publish_pypi (only on main, only when version bumped)
All jobs run on the self-hosted EC2 GitLab runner (tags: [ec2-instance]).
PyPI authentication
poetry publish reads the POETRY_PYPI_TOKEN_PYPI env var (Poetry's standard
convention). It's configured as a GitLab CI/CD Variable on the project
(Settings → CI/CD → Variables): masked, scope = All environments.
Rotation = generate a new project-scoped token at https://pypi.org/manage/account/token/
(scope = reach-commons), paste into the same CI/CD Variable, revoke the old.
No restart or SSH needed.
Branches
| Branch | Purpose |
|---|---|
main |
source of truth; merges here trigger PyPI publish when version bumped |
fix/*, feat/*, chore/* |
working branches; verify pipeline runs but no publish |
Architecture cheat-sheet
consumer Lambda
│
├─ os.environ[lambda_function_api_key] ──┐
│ ▼
│ reach_commons.clients._auth.reach_api_bearer_header()
│ │
├─ EventProcessorClient ────────────────┤
├─ CallbackProcessorClient ────────────────┤ "Authorization": "Bearer <token>"
├─ ReachOpsApiClient ────────────────┤
└─ ReachDataBridgeClient ────────────────┘
Four client classes share the same Bearer token via a single helper — drop the
env var on the Lambda and all four start sending Bearer (empty) → 401s.
Test layout
All test files in tests/ use @pytest.mark.parametrize. Adding a non-parametrized
def test_x is discouraged — collapse into parameters or split if behaviors truly
diverge.
| File | Coverage |
|---|---|
test_imports.py |
parametrized over every reach_commons.* module via pkgutil.walk_packages — auto-discovers new submodules |
test_sms_smart_encoding.py |
GSM-7 / UCS-2 detection, normalization map, segment math at length boundaries (160/161/306/307, 70/71) |
test_validations.py |
Twilio HTTP wrapper status-code → bool fork; env var precedence (uppercase / lowercase / unset) |
test_auth.py |
reach_api_bearer_header() with token set / empty / unset |
test_outscraper.py |
env var → constructor → empty fallback resolution; X-API-KEY header |
Migration history
- 2026-05-12 — Migrated from AWS CodeCommit (
reach-commons→ renamed toreach-commons-MOVED-TO-GITLAB, read-only archive) to GitLab. Replaced manualpython build.pypublish with GitLab CI publish-on-version-bump. Removed hardcoded secrets from the wheel (Twilio creds, Bearer tokens shared across four internal-API clients, Outscraper token + webhook URL); all secrets now read from env vars sourced from/terraform/shared-config.tfSSM. Adopted ruff (replacing black + isort) and pyright; added parametrized test suite. Version 0.18.55 → 0.18.56.
Service ownership
Owner: Reach Engineering. Issues / MR reviews via the GitLab repo. The legacy
CodeCommit archive at reach-commons-MOVED-TO-GITLAB is read-only and kept
only for git archaeology.
4 maintainers
Release files for reach_commons 0.18.78
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Total release size: 104.8 kB
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