walt.id — "Bulk from PostgreSQL"

DPG: walt.id (walt_community). Bulk source key: db (declared in scripts/gen-backends.sh, walt.id stanza).
Connector: queryDBRows in internal/handlers/bulk.go — a read-only pgx connection; only statements whose first token is SELECT are accepted; a 15 s query timeout applies.

walt.id already declares the db bulk source, so the chip renders and works with any Postgres the
verifiably-go container can reach. This page is the operator recipe for the repo's demo database.

1. Demo database (config only, no code)

The fixture in testdata/bulk-issuance/docker-compose.yml brings up a seeded Postgres 16
(ministry-citizens-db, 201 synthetic citizens from deploy/compose/stack/citizens-db/init.sql,
published on host port 5437) plus a small JSON API (ministry-citizens-service, host port 8199).
The compose file joins both containers to the external network waltid_default (the compose
project name of the main stack), so the verifiably-go container reaches them by container name:

cd verifiably-go/testdata/bulk-issuance && docker compose up -d
# (the compose already attaches to waltid_default; if it was created before the main stack, re-attach:)
docker network connect waltid_default ministry-citizens-db      2>/dev/null || true
docker network connect waltid_default ministry-citizens-service 2>/dev/null || true
docker exec ministry-citizens-db psql -U citizens -c 'SELECT count(*) FROM citizens'   # → 201

2. What to type in the UI

Issuer → walt.id DPG → pick a schema → Bulk → Bulk from PostgreSQL.

Field	Value
Postgres connection string	postgres://citizens:citizens@ministry-citizens-db:5432/citizens?sslmode=disable (same host, verifiably-go in Docker)
	postgres://citizens:citizens@localhost:5437/citizens?sslmode=disable (verifiably-go run on bare metal with go run)
SELECT query	one of the paste-ready recipes in testdata/bulk-issuance/db/queries.sql, e.g. below

DSN pattern: postgres://<user>:<pass>@<container>:5432/<db>?sslmode=disable — <container> is the
Postgres container's name on the shared Docker network (host port publication is only for humans).

Sample SELECT (works with any schema that has a holder-like field; the column aliases become the
source columns you map to credential fields in the next step):

SELECT
  first_name || ' ' || last_name AS holder
FROM citizens
ORDER BY id
LIMIT 20;

Expected: "db — 20 rows · map columns → fields", one column holder; Issue 20 credentials →
renders 20 offer URIs/QR codes. The VerifiableId recipe in queries.sql (WHERE address IS NOT NULL … LIMIT 15)
yields 15 rows with the eight walt.id VerifiableId field names pre-mapped by exact name.

3. Failure messages you may see

Message	Cause
Connection string and SELECT query are both required.	a field is empty
Fetch failed: only SELECT queries allowed	first token of the query is not SELECT
Fetch failed: failed to connect …	DSN unreachable from the container (wrong host, not on waltid_default)
Fetch failed: query returned 0 rows	the WHERE clause matched nothing

Tests: TestBulkPreview_DB_WaltID (internal/handlers/bulk_test.go) and TestQueryDBRows_FailsBeforeConnecting;
the walt.id capability list is pinned by scripts/ci/test-gen-backends.sh.