refactor(sdk)!: extract pj_datastore to the app repo; SDK now Apache-2.0 (#113)

The columnar storage engine (pj_datastore) was the only MPL-2.0 part of this
package and the only component plugins never link: plugins reach storage
through the pj_base C ABI, and the host-side write bridges live in the engine.
Move it into the PlotJuggler application repo so this submodule is purely the
plugin SDK (pj_base + pj_plugins).

- Remove pj_datastore/ entirely and the datastore Conan/CMake component, the
  with_datastore / with_parquet_example options, and the nanoarrow / tsl /
  benchmark detection that existed only for the engine.
- License is now Apache-2.0 in full (drop LICENSE-MPL); update LICENSE/README.
- Bump 0.5.1 -> 0.6.0 (removing the datastore component is an API removal).
- Update CI workflows, the SDK install smoke-test, and docs (CLAUDE.md,
  V4_STORE.md, pj_plugins docs) to reflect the new engine location.

BREAKING CHANGE: the `datastore` CMake/Conan component is removed from
plotjuggler_core. Consumers that need the storage engine must depend on it in
the application repo; plugins are unaffected (they use base/plugin_sdk/plugin_host).

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: facontidavide

.github/workflows/linux-ci.yml

@@ -169,7 +169,6 @@ jobs:
           conan install . --output-folder=build --build=missing
           -s build_type=RelWithDebInfo -s compiler.cppstd=20
           -o "plotjuggler_core/*:with_tests=True"
-          -o "plotjuggler_core/*:with_parquet_example=False"
 
       - name: Save Conan cache to ghcr.io
         # Only push from the canonical repo on real pushes (forks lack write
@@ -208,7 +207,6 @@ jobs:
           -DCMAKE_BUILD_TYPE=RelWithDebInfo
           -DCMAKE_C_COMPILER_LAUNCHER=ccache
           -DCMAKE_CXX_COMPILER_LAUNCHER=ccache
-          -DPJ_BUILD_PARQUET_IMPORT_EXAMPLE=OFF
           -DPJ_ENABLE_ABI_CHECK=ON
 
       - name: Build

.github/workflows/macos-ci.yml

@@ -30,14 +30,12 @@ jobs:
           conan install . --output-folder=build --build=missing
           -s build_type=RelWithDebInfo -s compiler.cppstd=20
           -o "plotjuggler_core/*:with_tests=True"
-          -o "plotjuggler_core/*:with_parquet_example=False"
 
       - name: Configure
         run: >
           cmake -S . -B build -G Ninja
           -DCMAKE_TOOLCHAIN_FILE=${{ github.workspace }}/build/conan_toolchain.cmake
           -DCMAKE_BUILD_TYPE=RelWithDebInfo
-          -DPJ_BUILD_PARQUET_IMPORT_EXAMPLE=OFF
 
       - name: Build
         run: cmake --build build

.github/workflows/release.yml

@@ -261,5 +261,5 @@ jobs:
             ```
 
             See [README.md](https://github.com/PlotJuggler/plotjuggler_core/blob/main/README.md)
-            for available components (`base`, `datastore`, `plugin_sdk`, `plugin_host`)
+            for available components (`base`, `plugin_sdk`, `plugin_host`)
             and consumer examples.

.github/workflows/windows-ci.yml

@@ -177,7 +177,6 @@ jobs:
           -DCMAKE_TOOLCHAIN_FILE=${{ github.workspace }}/build/conan_toolchain.cmake
           -DCMAKE_C_COMPILER_LAUNCHER=sccache
           -DCMAKE_CXX_COMPILER_LAUNCHER=sccache
-          -DPJ_BUILD_PARQUET_IMPORT_EXAMPLE=OFF
 
       - name: Build
         run: cmake --build build --config Release

CLAUDE.md

@@ -2,10 +2,15 @@
 
 ## Project Overview
 
-PlotJuggler Core — C++20 foundation libraries for PlotJuggler storage, plugin SDKs, and host-side
+PlotJuggler Core — C++20 foundation libraries that make up the PlotJuggler plugin SDK and host-side
 plugin loading. **Read-only submodule** inside PJ4: consumed as-is; changes happen in this repo,
 not in the PJ4 superproject. This file is the single navigation node for the whole submodule — the
-three modules below have no own CLAUDE.md.
+two modules below have no own CLAUDE.md.
+
+> The columnar storage engine (`pj_datastore`) used to live here. It now lives in the PlotJuggler
+> application repo as a top-level module: plugins reach storage only through the C ABI defined in
+> `pj_base` (the host-side write implementations are not part of the SDK), so the engine does not
+> belong in the plugin SDK.
 
 ### Modules
 
@@ -15,16 +20,13 @@ three modules below have no own CLAUDE.md.
   SceneEntities, RobotDescription, CameraInfo, Log, ImageAnnotations, FrameTransforms) and their 14
   wire codecs (RobotDescription carries source text as-is — no codec), the C-ABI protocol headers for
   DataSource/MessageParser/Toolbox + the C++ SDK base classes / host-view helpers built on them.
-- **pj_datastore** — columnar storage engine (`DataEngine`) + `ObjectStore` (media/opaque blobs) +
-  `DerivedEngine` (fmt, tsl::robin_map, nanoarrow). Plugin-data host implementations live here.
 - **pj_plugins** — host-side loaders + RAII handles + plugin discovery/catalog for four plugin
   families (DataSource, MessageParser, Dialog, Toolbox), config-envelope helpers, and the **dialog
   C ABI** (`pj_plugins/dialog_protocol/`). Note the split: the DataSource/MessageParser/Toolbox C-ABI
   protocol headers live in `pj_base`; the **Dialog** protocol header lives here, not in `pj_base`.
 
 ### Dependency graph
 
-- `pj_datastore` → `pj_base` (+ fmt, nanoarrow)
 - `pj_plugins` → `pj_base` (+ nlohmann/json)
 
 ## Read path
@@ -53,11 +55,6 @@ documentation check before commit.
 | `docs/toolbox-porting-gap-analysis.md` | Historical PJ3→PJ4 toolbox SDK gap analysis (most gaps now closed; read as context, not current reference) |
 | `V4_STORE.md` | ObjectStore plugin ABI: services, ownership rules, lazy fetch |
 
-**Datastore** (`pj_datastore/docs/`): `REQUIREMENTS.md` (data model, ingest contract, schema
-evolution, query) · `ARCHITECTURE.md` (domain model, layers, encoding, DerivedEngine) ·
-`USER_GUIDE.md` (plugin-author write/read patterns, ValueRef, TypedNull) ·
-`OBJECT_STORE_DESIGN.md` (lazy-fetch blobs, retention).
-
 **Plugin system** (`pj_plugins/docs/`): `REQUIREMENTS.md` (families, capability system, config
 contract) · `ARCHITECTURE.md` (C ABI protocols, SDK base classes, host loaders, dialog protocol) ·
 `data-source-guide.md` · `message-parser-guide.md` · `dialog-plugin-guide.md` · `toolbox-guide.md`.
@@ -123,7 +120,7 @@ or push a release without the user's go-ahead.
 ## Instructions Glossary
 
 - **"Read all documentation"** — read every `.md` in the tree (`find . -name '*.md'`), including
-  `docs/`, `pj_datastore/docs/`, `pj_plugins/docs/`.
+  `docs/` and `pj_plugins/docs/`.
 - **"Update the documentation"** — correct any doc made outdated/inaccurate this session; if a doc
   disagrees with code, fix the doc to match reality; add info whose absence caused a bug.
 - **"Check documentation"** — review the docs related to the changed module/API; confirm they still

CMakeLists.txt

@@ -16,13 +16,7 @@ include(PjPluginManifest)
 option(PJ_ASSERT_THROWS "Use exceptions instead of assert() for PJ_ASSERT" OFF)
 option(PJ_ENABLE_SANITIZERS "Enable ASAN for Debug builds" OFF)
 option(PJ_ENABLE_TSAN "Enable ThreadSanitizer for Debug builds" OFF)
-option(PJ_INSTALL_SDK "Install plotjuggler_core CMake package (base/datastore/plugin_sdk/plugin_host)" OFF)
-option(
-  PJ_BUILD_PARQUET_IMPORT_EXAMPLE
-  "Build parquet_import example (requires full Arrow C++ and Parquet)"
-  ON
-)
-option(PJ_BUILD_DATASTORE "Build pj_datastore module (requires nanoarrow)" ON)
+option(PJ_INSTALL_SDK "Install plotjuggler_core CMake package (base/plugin_sdk/plugin_host)" OFF)
 option(PJ_BUILD_PORTED_PLUGINS "Build pj_ported_plugins (ported plugins collection)" ON)
 option(PJ_BUILD_TESTS "Build tests, benchmarks, and examples" ON)
 option(PJ_ENABLE_ABI_CHECK "Enable abidiff-based ABI drift gate (requires libabigail)" OFF)
@@ -87,87 +81,6 @@ target_link_libraries(pj_internal_fmt INTERFACE ${PJ_FMT_TARGET})
 # package under the capitalised name `FastFloat`.
 find_package(FastFloat REQUIRED)
 
-if(PJ_BUILD_DATASTORE)
-  find_package(tsl-robin-map REQUIRED)
-  if(PJ_BUILD_TESTS)
-    find_package(benchmark CONFIG REQUIRED)
-  endif()
-
-# --- nanoarrow core ---
-
-find_package(nanoarrow CONFIG QUIET)
-
-set(PJ_NANOARROW_TARGET "")
-if(TARGET nanoarrow::nanoarrow)
-  set(PJ_NANOARROW_TARGET nanoarrow::nanoarrow)
-elseif(TARGET nanoarrow::nanoarrow_static)
-  set(PJ_NANOARROW_TARGET nanoarrow::nanoarrow_static)
-elseif(TARGET nanoarrow::nanoarrow_shared)
-  set(PJ_NANOARROW_TARGET nanoarrow::nanoarrow_shared)
-else()
-  find_package(PkgConfig QUIET)
-  if(PkgConfig_FOUND)
-    pkg_check_modules(NANOARROW QUIET nanoarrow)
-    if(NANOARROW_FOUND)
-      add_library(pj_nanoarrow INTERFACE)
-      target_include_directories(pj_nanoarrow INTERFACE
-        ${NANOARROW_INCLUDE_DIRS}
-      )
-      target_link_libraries(pj_nanoarrow INTERFACE ${NANOARROW_LIBRARIES})
-      set(PJ_NANOARROW_TARGET pj_nanoarrow)
-    endif()
-  endif()
-endif()
-
-if(PJ_NANOARROW_TARGET STREQUAL "")
-  message(FATAL_ERROR
-    "nanoarrow is required for pj_datastore. "
-    "Install nanoarrow and expose a CMake target "
-    "(nanoarrow::nanoarrow / nanoarrow::nanoarrow_static / nanoarrow::nanoarrow_shared) "
-    "or provide a pkg-config entry named 'nanoarrow'."
-  )
-endif()
-
-# --- nanoarrow IPC ---
-
-set(PJ_NANOARROW_IPC_TARGET "")
-if(TARGET nanoarrow::nanoarrow_ipc)
-  set(PJ_NANOARROW_IPC_TARGET nanoarrow::nanoarrow_ipc)
-elseif(TARGET nanoarrow::nanoarrow_ipc_static)
-  set(PJ_NANOARROW_IPC_TARGET nanoarrow::nanoarrow_ipc_static)
-elseif(TARGET nanoarrow::nanoarrow_ipc_shared)
-  set(PJ_NANOARROW_IPC_TARGET nanoarrow::nanoarrow_ipc_shared)
-else()
-  if(PkgConfig_FOUND)
-    pkg_check_modules(NANOARROW_IPC QUIET nanoarrow_ipc)
-    if(NANOARROW_IPC_FOUND)
-      add_library(pj_nanoarrow_ipc INTERFACE)
-      target_include_directories(pj_nanoarrow_ipc INTERFACE
-        ${NANOARROW_IPC_INCLUDE_DIRS}
-      )
-      target_link_libraries(pj_nanoarrow_ipc INTERFACE ${NANOARROW_IPC_LIBRARIES})
-      set(PJ_NANOARROW_IPC_TARGET pj_nanoarrow_ipc)
-    endif()
-  endif()
-endif()
-
-if(PJ_NANOARROW_IPC_TARGET STREQUAL "")
-  message(FATAL_ERROR
-    "nanoarrow IPC is required for pj_datastore. "
-    "Install nanoarrow with IPC support and expose a CMake target "
-    "(nanoarrow::nanoarrow_ipc / nanoarrow::nanoarrow_ipc_static / nanoarrow::nanoarrow_ipc_shared) "
-    "or provide a pkg-config entry named 'nanoarrow_ipc'."
-  )
-endif()
-
-# nanoarrow IPC internally depends on the flatcc runtime (libflatccrt).
-# Some package managers (e.g. Conan) bundle it alongside the IPC library
-# but don't declare it as a transitive link dependency. Since the IPC target
-# already sets INTERFACE_LINK_DIRECTORIES, linking by name suffices.
-target_link_libraries(${PJ_NANOARROW_IPC_TARGET} INTERFACE flatccrt)
-
-endif() # PJ_BUILD_DATASTORE
-
 # ---------------------------------------------------------------------------
 # Modules
 # ---------------------------------------------------------------------------
@@ -177,9 +90,6 @@ if(PJ_BUILD_TESTS)
 endif()
 
 add_subdirectory(pj_base)
-if(PJ_BUILD_DATASTORE)
-  add_subdirectory(pj_datastore)
-endif()
 add_subdirectory(pj_plugins)
 
 if(PJ_BUILD_PORTED_PLUGINS AND EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/pj_ported_plugins/CMakeLists.txt")
@@ -193,7 +103,6 @@ endif()
 # Exported CMake namespace: plotjuggler_core::
 # Components:
 #   base         — vocabulary types (always available)
-#   datastore    — columnar engine (optional, requires PJ_BUILD_DATASTORE)
 #   plugin_sdk   — plugin-author surface: base + dialog SDK + parser SDK
 #   plugin_host  — host-side loaders (data_source, message_parser, toolbox,
 #                  dialog, catalogs)
@@ -202,7 +111,7 @@ endif()
 if(PJ_INSTALL_SDK)
   include(CMakePackageConfigHelpers)
 
-  set(PJ_PACKAGE_VERSION "0.5.1")
+  set(PJ_PACKAGE_VERSION "0.6.0")
   set(PJ_PACKAGE_CMAKE_DIR ${CMAKE_INSTALL_LIBDIR}/cmake/plotjuggler_core)
 
   install(EXPORT plotjuggler_coreTargets

LICENSE

@@ -6,7 +6,6 @@ SPDX-License-Identifier header that is authoritative for that file.
   pj_base         Apache-2.0     LICENSE-APACHE
   pj_plugins      Apache-2.0     LICENSE-APACHE
   examples        Apache-2.0     LICENSE-APACHE
-  pj_datastore    MPL-2.0        LICENSE-MPL
 
 Rationale:
 
@@ -15,12 +14,8 @@ Rationale:
     the SDK without restriction. Apache-2.0 also grants an explicit patent
     license to downstream users.
 
-  - The storage engine (pj_datastore) is MPL-2.0. MPL-2.0 is file-level
-    (weak) copyleft: modifications to the engine's own source files must be
-    published, but the engine may be combined with proprietary code and
-    linked into proprietary applications.
-
-Plugins load through a stable C ABI and never statically link pj_datastore,
-so the MPL-2.0 engine imposes no obligations on plugin authors.
+The columnar storage engine (formerly the MPL-2.0 `pj_datastore` module) has
+moved to the PlotJuggler application repository; this SDK is now Apache-2.0
+in its entirety.
 
 Copyright (c) 2026 Davide Faconti