Add pg_lake extension for Iceberg and data lake access

- Add pg_lake extension from Snowflake Labs to the Docker image
- Build pg_lake with all core extensions (pg_map, pg_extension_base,
  pg_extension_updater, pg_lake_engine, pg_lake_copy, pg_lake_iceberg,
  pg_lake_table, pg_lake)
- Build and include Apache Avro library required by pg_lake
- Add runtime dependencies for pg_lake (snappy, jansson, lz4, xz, zstd, libpq)
- Update README to document pg_lake extension
- Update Makefile test to verify pg_lake extension loads correctly

Note: DuckDB/pgduck_server integration is not included due to Alpine Linux
compatibility constraints. The core pg_lake extensions provide Iceberg table
support and data lake file access capabilities.

Author: pyramation

Dockerfile

@@ -1,11 +1,12 @@
-# Lean PostgreSQL image with pgvector, PostGIS, pg_textsearch, and pgsodium
+# Lean PostgreSQL image with pgvector, PostGIS, pg_textsearch, pgsodium, and pg_lake
 # Multi-stage build - all toolchains discarded, only artifacts kept
 
 ARG PG_VERSION=17
 ARG PGVECTOR_VERSION=0.8.0
 ARG POSTGIS_VERSION=3.5.1
 ARG PG_TEXTSEARCH_VERSION=0.2.0
 ARG PGSODIUM_VERSION=3.1.9
+ARG PG_LAKE_VERSION=main
 
 #############################################
 # Stage 1: Build extensions
@@ -16,6 +17,7 @@ ARG PGVECTOR_VERSION
 ARG POSTGIS_VERSION
 ARG PG_TEXTSEARCH_VERSION
 ARG PGSODIUM_VERSION
+ARG PG_LAKE_VERSION
 
 RUN apk add --no-cache \
     git \
@@ -36,7 +38,18 @@ RUN apk add --no-cache \
     # PostGIS build tools
     perl \
     flex \
-    bison
+    bison \
+    # pg_lake dependencies
+    cmake \
+    ninja \
+    openssl-dev \
+    snappy-dev \
+    jansson-dev \
+    lz4-dev \
+    xz-dev \
+    zstd-dev \
+    libpq-dev \
+    linux-headers
 
 WORKDIR /build
 
@@ -70,6 +83,25 @@ RUN git clone --branch v${PGSODIUM_VERSION} --depth 1 https://github.com/michelp
     make -j$(nproc) && \
     make install
 
+# pg_lake - Postgres with Iceberg and data lake access
+RUN git clone --branch ${PG_LAKE_VERSION} --depth 1 --recurse-submodules https://github.com/Snowflake-Labs/pg_lake.git && \
+    cd pg_lake && \
+    # Build and install avro library
+    cd avro && git checkout -f . && git apply --ignore-whitespace ../avro.patch && \
+    mkdir -p lang/c/build && cd lang/c/build && \
+    cmake .. -DCMAKE_INSTALL_PREFIX=/usr/local -DCMAKE_BUILD_TYPE=RelWithDebInfo && \
+    make -j$(nproc) && make install && \
+    cd /build/pg_lake && \
+    # Build pg_lake extensions (without DuckDB/pgduck_server for Alpine compatibility)
+    make -C pg_map && make -C pg_map install && \
+    make -C pg_extension_base && make -C pg_extension_base install && \
+    make -C pg_extension_updater && make -C pg_extension_updater install && \
+    make -C pg_lake_engine && make -C pg_lake_engine install && \
+    make -C pg_lake_copy && make -C pg_lake_copy install && \
+    make -C pg_lake_iceberg && make -C pg_lake_iceberg install && \
+    make -C pg_lake_table && make -C pg_lake_table install && \
+    make -C pg_lake && make -C pg_lake install
+
 #############################################
 # Stage 2: Final lean runtime image
 #############################################
@@ -84,11 +116,20 @@ RUN apk add --no-cache \
     protobuf-c \
     libxml2 \
     pcre2 \
-    libsodium
+    libsodium \
+    # pg_lake runtime dependencies
+    snappy \
+    jansson \
+    lz4-libs \
+    xz-libs \
+    zstd-libs \
+    libpq
 
 # Copy compiled extensions from builder
 COPY --from=builder /usr/local/lib/postgresql/ /usr/local/lib/postgresql/
 COPY --from=builder /usr/local/share/postgresql/ /usr/local/share/postgresql/
+# Copy avro library for pg_lake
+COPY --from=builder /usr/local/lib/libavro* /usr/local/lib/
 
 LABEL org.opencontainers.image.source="https://github.com/constructive-io/docker"
-LABEL org.opencontainers.image.description="PostgreSQL 17 with pgvector, PostGIS, pg_textsearch, and pgsodium"
+LABEL org.opencontainers.image.description="PostgreSQL 17 with pgvector, PostGIS, pg_textsearch, pgsodium, and pg_lake"

Makefile

@@ -40,6 +40,7 @@ test: build
 		CREATE EXTENSION postgis; \
 		CREATE EXTENSION pg_textsearch; \
 		CREATE EXTENSION pgsodium; \
+		CREATE EXTENSION pg_lake; \
 		SELECT 'all extensions OK';"
 	@docker stop $(CONTAINER_NAME)-test > /dev/null
 	@docker rm $(CONTAINER_NAME)-test > /dev/null

README.md

@@ -14,6 +14,7 @@ Lean PostgreSQL 17 image with essential extensions for modern applications.
 | [PostGIS](https://postgis.net/) | Spatial and geographic data |
 | [pg_textsearch](https://www.tigerdata.com/docs/use-timescale/latest/extensions/pg-textsearch) | BM25 full-text search |
 | [pgsodium](https://github.com/michelp/pgsodium) | Encryption using libsodium |
+| [pg_lake](https://github.com/Snowflake-Labs/pg_lake) | Iceberg and data lake access |
 
 ## Usage
 
@@ -36,6 +37,7 @@ CREATE EXTENSION vector;
 CREATE EXTENSION postgis;
 CREATE EXTENSION pg_textsearch;
 CREATE EXTENSION pgsodium;
+CREATE EXTENSION pg_lake;
 ```
 
 ## Build