procurement-ingest/lambdas/wo/email_processor
Adam Moussa acc1961d21
feat: template-first WO parser + Bedrock fallback, PO Bedrock switch (#99)
* Add deterministic template parser for WO emails

The workorder-email-processor sends every one of ~22.9k emails/month to
an LLM, but ~93.6% are the plain-text "AMAZON UPDATE WO DETAILS" comment
template and ~6.4% the HTML "AMAZON assign Work Order" template. Parse
those two shapes deterministically, offline, so the AI call is reserved
for the long tail.

The module is pure (no boto3, no network). try_deterministic_parse
classifies by subject, extracts the shared contract fields, and returns
a result ONLY when it passes a strict fail-closed validation gate: exact
contract-key set, subject/id agreement, the literal "Work Order:  <id>"
double space, per-type required fields, site-code shape, and a
label-bleed guard so a value that over-ran into the next field fails.
Any miss, drift, or extractor exception yields None so the caller falls
back to the AI extractor -- data is never corrupted, only the fallback
rate rises.

Refs: #23

* Migrate WO processor to Bedrock and fix comment_id collision

Switch the AI path from the Anthropic SDK to bedrock-runtime InvokeModel
on the inference profile us.anthropic.claude-haiku-4-5-20251001-v1:0
(BEDROCK_MODEL_ID env), so parsing no longer needs a provider API key or
Secrets Manager secret. The EXTRACTION_PROMPT and JSON contract are kept
byte-identical, so the AI-fallback output is unchanged. Try the new
deterministic template parser first and only call Bedrock on a
miss/invalid result.

Fix issue #23: the WorkOrderComments range key was
work_order_id#<comment_time>, so two emails on one WO with an identical
or absent comment time collided and overwrote each other. Derive a
12-hex suffix from the S3 object key alone -- deterministic, so an async
retry of the same object is byte-identical (idempotent) while distinct
emails get distinct keys -- and keep wall-clock now() out of the key
(literal 'nocomment' segment when comment_time is absent).

Also emit one CloudWatch EMF line per record (Seahaven/WorkorderIngest
ParseOutcome, dimensioned by ParseMethod/TemplateId) for parse-outcome
observability, replace the deprecated datetime.utcnow() with
datetime.now(timezone.utc), and drop the anthropic dependency.

Refs: #23

* Migrate PO processor to Bedrock

Switch the PO email processor's AI extraction from the Anthropic SDK to
bedrock-runtime InvokeModel on the inference profile
us.anthropic.claude-haiku-4-5-20251001-v1:0 (BEDROCK_MODEL_ID env), so
it no longer needs a provider API key or Secrets Manager secret. PO
parsing stays fully AI -- only the provider changes. The EXTRACTION_PROMPT
is kept byte-identical and the Bedrock text output is still decoded with
json.loads(..., parse_float=Decimal), which DynamoDB requires (it rejects
floats). Replace the deprecated datetime.utcnow() with
datetime.now(timezone.utc) and drop the anthropic dependency.

* Grant Bedrock IAM, drop Anthropic secrets, add fallback alarm

Both stacks moved their processors from the Anthropic API to the Bedrock
inference profile us.anthropic.claude-haiku-4-5-20251001-v1:0. Grant each
processor role bedrock:InvokeModel + bedrock:InvokeModelWithResponseStream
on BOTH the inference-profile ARN AND the per-region foundation-model
ARNs for us-east-1/us-east-2/us-west-2 (empty-account) -- the us.* profile
routes cross-region, so a profile-only grant AccessDenies at runtime.

Remove both anthropic-api-key Secret constructs, their grant_read, and
the ANTHROPIC_API_KEY_SECRET_ARN env; add BEDROCK_MODEL_ID. The secrets
had RemovalPolicy.RETAIN so they are orphaned, not deleted -- flagged in
the README for manual post-deploy deletion and key revocation.

Add the workorder-email-processor-template-fallback-rate alarm: a
FILL(0) + >=10-sample volume-floor MathExpression over the EMF
ParseOutcome metric (15-min periods) that pages when the AI-fallback
share exceeds 15% sustained, catching Hexagon template drift. ALARM-only
SnsAction to site-alerts, no OK action, NOT_BREACHING, matching the
existing stack idiom.

* Add offline WO parser test suite

Cover the deterministic parser with golden-file tests over 55 real
scrubbed .eml fixtures (both comment sub-shapes, username Submitted-By,
address present/absent, br+CRLF assign addresses), fail-closed
validation-gate rules, adversarial and prompt-injection cases that must
route to ai_fallback or parse without corrupting other fields, the issue
#23 comment_id idempotency invariants, and the Bedrock-fallback dispatch
plus EMF-metric emission with a mocked invoke_model.

Extend pytest.ini testpaths to discover the co-located suite, and update
tests/conftest.load_handler to put a handler's own directory on sys.path
so the WO handler's new `from template_parser import ...` resolves under
the existing shared handler tests. Point test_local.py at the new
template-first + Bedrock flow.

Refs: #23

* Document Bedrock migration and WO parse flow in README

Record the provider switch to the Bedrock inference profile (no Anthropic
API key or Secrets Manager secret, with the retired secrets flagged for
manual deletion), the WO deterministic-template-first + AI-fallback flow,
the new ParseOutcome EMF metric and template-fallback-rate alarm, the
issue #23 comment_id format change, the +00:00 aware-UTC timestamp shift,
and offline test instructions.

Refs: #23

* Fix f-string lint and formatting in backfill scripts

Drop the f prefix from two f-strings that carry no placeholders
(F541) and apply ruff format, so `ruff check` / `ruff format --check`
pass in CI.

* Emit ParseMethod-only EMF set so fallback alarm can fire

The fallback-rate alarm queries the ParseOutcome series keyed on
ParseMethod alone, but the emitter published only the joint
(ParseMethod, TemplateId) dimension set. CloudWatch materializes
exactly the listed dimension sets and does not auto-aggregate, so the
alarm's series never received data: it evaluated a constant 0 and
could never page on template-drift coverage collapse.

Publish both ["ParseMethod"] and ["ParseMethod","TemplateId"] and
update the EMF regression test to assert both sets are present.

* Commit WO parser .eml fixtures for executable coverage

The parser test suite globbed for input .eml fixtures that the repo's
`*.eml` ignore rule kept uncommitted, so every parametrized golden and
fail-closed test collected zero cases and CI could not exercise the
deterministic parser that handles 100% of WO email volume.

Add a fixtures-only negation to .gitignore and commit the 55 scrubbed
positive samples (50 update-plaintext, 5 assign-html) plus 14
ai-fallback and 3 adversarial fixtures. The ai-fallback set covers each
fail-closed reason code (subject_no_match, single_space_work_order,
malformed_site_code, label_bleed, creation_time_unparseable,
wo_id_mismatch, missing_required_field) and the adversarial set proves
the parser is total and confines prompt-injection payloads to
comment_text without steering the structured fields.

* Fix WO parser advisories A1-A3 (PR #99 follow-ups)

A1 — AI-fallback comment_id nondeterminism: parsed comment_time is model
output and not stable across Lambda async retries, so on the ai_fallback
path the comment_id range-key time segment now derives from the email Date
header (deterministic per S3 object) instead of the model's comment_time.
The template path is unchanged (its comment_time is a pure function of the
raw email). Bedrock invoke pins temperature 0 so retries reproduce the same
extraction. Closes the #23 reopening on the AI path.

A2 — EMF record now carries the spec-required _aws.Timestamp (epoch ms) so
CloudWatch reliably extracts the ParseOutcome datapoint that the
fallback-rate alarm depends on.

A3 — T1 New Comment capture no longer truncates at the first blank line;
multi-paragraph comments are captured through internal blanks and terminate
at the next label/separator. 17 golden files regenerated from the real
fixtures accordingly.

Hardening from the sh-security-review pass on this diff:
- _header_date_iso is total: OverflowError/OSError from an extreme Date
  header fall back to 'nocomment' instead of failing the invocation.
- _capture_block trims blanks in O(n) (no pop(0)) — removes a quadratic
  path on a crafted large blank run.
- work_order_id is enforced digits-only on BOTH parse paths before it is
  used as a DynamoDB key, so prompt-injected AI output cannot forge '#'
  range-key segments or land on an arbitrary WO.
2026-07-16 12:45:11 -04:00
..
tests feat: template-first WO parser + Bedrock fallback, PO Bedrock switch (#99) 2026-07-16 12:45:11 -04:00
__init__.py Merge workorder-ingest into unified procurement repo (#22) 2026-05-12 15:21:06 -04:00
handler.py feat: template-first WO parser + Bedrock fallback, PO Bedrock switch (#99) 2026-07-16 12:45:11 -04:00
requirements.txt feat: template-first WO parser + Bedrock fallback, PO Bedrock switch (#99) 2026-07-16 12:45:11 -04:00
ses_auth.py Add fail-closed SES sender authentication (INFRA-107) (#98) 2026-07-15 20:58:47 -04:00
template_parser.py feat: template-first WO parser + Bedrock fallback, PO Bedrock switch (#99) 2026-07-16 12:45:11 -04:00