procurement-ingest/README.md

# PO Ingest

Coupa purchase-order email ingestion pipeline. SES receives Amazon PO emails, Claude extracts structured data, and the result lands in the shared `purchase-orders` DynamoDB table.

## Flow

1. Coupa sends a PO email to `amazon_po@int.seahaven.com`.
2. SES (using the shared `INBOUND_MAIL` rule set) drops the raw MIME into `s3://po-ingest-emails-{AccountId}/inbound/`.
3. S3 `ObjectCreated` fires the `po-email-processor` Lambda.
4. The Lambda parses the email, sends it to Claude Haiku 4.5 for structured JSON extraction, and writes to DynamoDB.
   - `email_type: new_po` — conditional `PutItem` on `purchase-orders` (idempotent on `po_number`).
   - `email_type: cancellation` — `UpdateItem` marking the existing row `Cancelled`.
5. DynamoDB Streams (NEW_AND_OLD_IMAGES) on `purchase-orders` feeds two downstream consumers:
   - **LedgerFlow** (`seahaven-slack-bot/po-sync`) — daily KB sync.
   - **Verified-sites pipeline** (`po-ingest-site-extractor`) — real-time site address extraction (see below).

A separate `po-web-ui` Lambda (Function URL, unauthenticated) renders a simple HTML dashboard scanning the table.

### Verified-sites pipeline

The `po-ingest-site-extractor` Lambda is triggered by the DynamoDB Stream on every PO INSERT/MODIFY. It:

1. Extracts an Amazon facility site code from `ship_to.name` using a regex cascade (parentheses, `LLC - CODE`, `Station CODE`, `DS - CODE`) with a fallback to the first `line_items` description.
2. Parses `ship_to.address` into structured fields (street, city, state, zip).
3. Upserts to the `verified-sites` DynamoDB table — atomically increments `poCount` and appends the PO number to `sourcePOs`.

POs with no extractable site code fall through to an address reverse-lookup against the verified-sites cache (normalized street + zip). If still unresolved, the PO is written to the `pending-site-review` table for manual verification against Payee Central.

Backfill stats (initial run): 14,825 POs scanned → 9,900 with extractable site codes → 1,100 unique sites.

## Architecture

- **IaC:** AWS CDK (Python), stack name `PoIngestStack`, region `us-east-1`.
- **Lambdas** (all Python 3.12, arm64, 60-day log retention):
  - `po-email-processor` — S3-triggered, parses PO emails via Claude Haiku.
  - `po-web-ui` — Function URL, HTML dashboard.
  - `po-ingest-site-extractor` — DynamoDB Streams-triggered, extracts site addresses.
- **Storage:**
  - S3 `po-ingest-emails-{AccountId}` — 90-day lifecycle expiry.
  - DynamoDB `purchase-orders` — owned by this stack, Streams enabled (NEW_AND_OLD_IMAGES).
  - DynamoDB `verified-sites` — PK `siteCode`, GSI `by-state` on `state`.
  - DynamoDB `pending-site-review` — PK `po_number`. POs with no extractable site code and no address match, awaiting manual Payee Central verification.
- **Secrets:** Anthropic API key in Secrets Manager at `po-ingest/anthropic-api-key`.
- **SES:** adds the `PoEmailRule` to the existing `INBOUND_MAIL` receipt rule set (shared with `workorder-ingest`).

## Setup

1. Bootstrap CDK in the account if you haven't already: `cdk bootstrap aws://{AccountId}/us-east-1`.
2. Store the Anthropic API key:
   ```bash
   aws secretsmanager create-secret \
     --name po-ingest/anthropic-api-key \
     --secret-string "sk-ant-..."
   ```
3. Install Lambda dependencies into the deployable package directory (gitignored):
   ```bash
   pip install -r lambdas/email_processor/requirements.txt -t lambdas/email_processor/package/
   ```
4. Deploy:
   ```bash
   cd cdk
   pip install -r requirements.txt
   cdk deploy
   ```
5. The `WebUIUrl` CloudFormation output is the dashboard URL.

## Reprocessing

To re-run the processor against every email still sitting in `inbound/` (useful after a parser change):

```bash
python scripts/reprocess.py            # dry-run — lists keys
python scripts/reprocess.py --execute  # invokes po-email-processor for each
```

Inserts are conditional on `po_number`, so re-processing existing POs is a no-op.

## Backfilling verified sites

The stream Lambda handles all future POs automatically. To backfill from historical PO data (one-time):

```bash
python scripts/backfill_sites.py
```

Uses the same extraction logic as the Lambda. Idempotent — safe to re-run.