OLake (github.com/datazip-inc/olake) is a CDC and ingestion engine that writes Apache Iceberg. It covers two paths none of the existing catalog suites reach. It is a strict Java Iceberg client. OLake does not write Iceberg from Go — its Go process spawns a Java sidecar over gRPC and writes through the official Apache Iceberg library, because the Go library has no equality deletes and CDC needs them. That makes it the client class weed/s3api/iceberg's metadata compliance backfill exists to serve: the one that fails with "Cannot parse missing long current-snapshot-id" when spec-required keys are omitted. And it produces equality deletes. Its upsert path commits operation=overwrite with an equality-delete file and a delete manifest. ClickHouse, Doris, Trino, Spark and DuckDB all only append, so nothing else in this directory exercises a delete manifest at all. Six subtests: the destination check reaches SUCCEEDED and actually loads the REST catalog; discover enumerates the source; a full sync commits a snapshot; PyIceberg reads back what the Java writer committed; an update plus a re-sync records an overwrite carrying equality deletes with a delete manifest in the current snapshot; and the catalog does not rewrite manifests the official Java writer produced, which gives the manifest-repair path a negative test to go with the ClickHouse positive one. What it deliberately does not assert is a delete-applied read. PyIceberg refuses to scan a table carrying equality deletes (apache/iceberg#6568) while reading its metadata fine, and an engine that can apply them costs a multi-gigabyte image. Recording the commit correctly is the catalog's contract; applying deletes on read is the engine's. The README says so, says the read half was verified by hand once with StarRocks, and warns against later "upgrading" this to a PyIceberg rows read — which would either fail or, if PyIceberg ever starts skipping deletes instead of raising, pass by not looking. The workflow job asserts the suite actually ran rather than trusting a green exit, for the same reason: at least one top-level PASS and zero SKIP. No product change — the destination config is the generic catalog_type=rest with the standard OAuth2 client-credentials flow, and s3_path_style is not even set, since OLake turns it on itself whenever s3_endpoint is non-empty. Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
OLake Iceberg Catalog Integration Test
An integration test for OLake against
SeaweedFS's Iceberg REST Catalog, in the same shape as catalog_clickhouse.
Why OLake, given we already test five engines
Two things here are covered by nothing else in this directory.
It is a strict Java Iceberg client. OLake does not write Iceberg from Go —
its Go process spawns a Java sidecar over gRPC and writes through the official
Apache Iceberg library, because the Go library has no equality deletes and CDC
needs them. So this test exercises the client class that
weed/s3api/iceberg/metadata_compliance.go exists to serve: the one
that fails with "Cannot parse missing long current-snapshot-id" when the
catalog omits spec-required keys that iceberg-go strips via omitempty.
It produces equality deletes. OLake is a CDC tool. Its upsert path commits
operation=overwrite with an equality-delete file, and a delete manifest
alongside the data manifests. ClickHouse, StarRocks, Doris and DuckDB all only
append.
What it asserts
TestOLakeIcebergCatalog runs six subtests against a weed mini cluster with
a pre-created table bucket and a Postgres source:
| Subtest | What a failure means |
|---|---|
CheckDestination |
olake check did not reach SUCCEEDED, or it passed without ever loading org.apache.iceberg.rest.RESTSessionCatalog — the second case means the destination was never actually contacted. |
Discover |
OLake could not enumerate the source table, or wrote no streams.json. |
FullSyncAppendsRows |
The sync read fewer than the three seeded rows, or committed no Iceberg snapshot. |
StrictReaderSeesRows |
PyIceberg could not read back what the Java writer committed, or the values differ. This is the data path, not just metadata. |
UpsertProducesEqualityDelete |
After an UPDATE and a re-sync, no snapshot recorded an overwrite carrying equality deletes, or the current snapshot has no delete manifest. |
CompliantWriterNeedsNoRepair |
The catalog rewrote a manifest the official Iceberg Java writer produced. That is a regression in the repair gate, not a problem with OLake. |
The one thing this test deliberately does not check
It does not assert that a reader sees the updated row and no duplicate.
PyIceberg refuses to scan a table carrying equality deletes (apache/iceberg#6568) while reading its metadata perfectly well — so a rows-mode read after the upsert would raise, not pass. The alternative is an engine that applies equality deletes, which for StarRocks means a 3 GB image and 12 GB of RAM in CI.
The line drawn instead: recording the commit correctly is the catalog's contract; applying deletes on read is the query engine's. The metadata assertions cover our half.
This was verified once by hand outside CI, on 2026-09-23, with StarRocks 4.1.4
attached to the same catalog: after the upsert it read 3 rows / 3 distinct ids
with id=1 showing the updated value and _op_type=u. If someone later wants
that inside the gate, add a reader that supports equality deletes — do not
"upgrade" this test to a PyIceberg rows-mode read after the upsert. It would not
pass; and if PyIceberg ever starts silently skipping deletes instead of raising,
it would pass by not looking.
What the config proves
Nothing in the destination config is SeaweedFS-specific:
{
"catalog_type": "rest",
"rest_catalog_url": "http://HOST:ICEBERG_PORT",
"iceberg_s3_path": "s3://olake-tables",
"s3_endpoint": "http://HOST:S3_PORT",
"rest_auth_type": "oauth2",
"oauth2_uri": "http://HOST:ICEBERG_PORT/v1/oauth/tokens",
"credential": "ACCESS_KEY:SECRET_KEY"
}
catalog_type is the generic rest, auth is the standard OAuth2
client-credentials flow, and s3_path_style does not even need setting —
OLake turns it on by itself whenever s3_endpoint is non-empty. As of
OLake v0.10.1 this works with no change on either side.
Running it
go test ./test/s3tables/catalog_olake/ -run TestOLakeIcebergCatalog -v -timeout 25m
Needs Docker and a weed binary (at weed/weed under the repo root, or on
PATH). Takes about 35 seconds. It skips rather than fails when Docker is
absent, and SEAWEEDFS_SKIP_OLAKE_TESTS=1 skips it outright.
Overrides: OLAKE_IMAGE (default olakego/source-postgres:latest),
POSTGRES_IMAGE (default postgres:16).
In CI
Runs as olake-iceberg-catalog-tests in .github/workflows/s3-tables-tests.yml,
on a matrix of a pinned image plus latest — the same shape the ClickHouse job
uses, and for the same reason: OLake's Iceberg writer is a Java sidecar whose
library version moves independently of the Go release, so the latest leg is
what catches drift in the client rather than in OLake itself.
The job asserts the suite actually ran — at least one top-level --- PASS and
zero --- SKIP — rather than trusting a green exit. This suite skips itself
when Docker is unavailable, and a skipped suite reporting success is how a gate
quietly stops being one.