title: "Configuring a developer environment"

description: >

output: rmarkdown::html_vignette

```{r setup-options, include=FALSE}

```{bash, save=run, hide=TRUE}

```{bash, save=run & windows, hide=TRUE}

Windows and macOS users who wish to contribute to the R package and

don't need to alter libarrow (Arrow's C++ library) may be able to obtain a

recent version of the library without building from source.

On Linux, you can download a .zip file containing libarrow from the

[nightly repository](https://nightlies.apache.org/arrow/r/libarrow/bin/).

The directory names correspond to the OS the binaries where built on:

- "centos-7" (gcc 8 via devtoolset, openssl 1, glib 2.17)

- "ubuntu-18.04" (gcc 8, openssl 1, glib 2.27)

- "ubuntu-22.04" (openssl 3)

Version numbers in that repository correspond to dates.

You'll need to create a `libarrow` directory inside the R package directory and unzip the zip file containing the compiled libarrow binary files into it.

On macOS, you can install libarrow using [Homebrew](https://brew.sh/):

brew install apache-arrow

brew install apache-arrow --HEAD

On Windows, you can download a .zip file containing libarrow from the

[nightly repository](https://nightlies.apache.org/arrow/r/libarrow/bin/windows/).

Version numbers in that repository correspond to dates.

You can set the `RWINLIB_LOCAL` environment variable to point to the zip file containing libarrow before installing the arrow R package.

If you need to alter both libarrow and the R package code, or if you can't get a binary version of the latest libarrow elsewhere, you'll need to build it from source. This section discusses how to set up a C++ libarrow build configured to work with the R package. For more general resources, see the [Arrow C++ developer guide](https://arrow.apache.org/docs/developers/cpp/building.html).

There are five major steps to the process.

When building libarrow, by default, system dependencies will be used if suitable versions are found. If system dependencies are not present, libarrow will build them during its own build process. The only dependencies that you need to install _outside_ of the build process are [cmake](https://cmake.org/) (for configuring the build) and [openssl](https://www.openssl.org/) if you are building with S3 support.

For a faster build, you may choose to pre-install more C++ library dependencies (such as [lz4](http://lz4.github.io/lz4/), [zstd](https://facebook.github.io/zstd/), etc.) on the system so that they don't need to be built from source in the libarrow build.

```{bash, save=run & ubuntu}

```{bash, save=run & macos}

The package can be built on Windows using [RTools 4](https://cran.r-project.org/bin/windows/Rtools/). It can be built for mingw32 (i386), mingw64 (x64), or ucrt64 (UCRT x64). mingw64 is the recommended 64-bit installation.

Open the corresponding RTools Bash, for example "Rtools MinGW 64-bit" for mingw64.

Install CMake, ccache, and Ninja with:

```{bash, save=run & windows}

You will need to add R to your path. For a user-level installation, R will be at something like `~/Documents/R/R-4.1.2/bin`. For a global installation, R will be at something like `/c/Program\ Files/R/R-4.1.2/bin`. The R on your path needs to match the architecture you are compiling for, so if you are compiling on 32-bit specify `.../bin/i386` instead of `.../bin/x64`.

You can install additional dependencies like so. Note that you are limited to the packages in [the RTools repo](https://github.com/r-windows/rtools-packages), which does not contain every dependency used by Arrow.

```{bash, save=run & windows}

We recommend that you configure libarrow to be built to a user-level directory rather than a system directory for your development work. This is so that the development version you are using doesn't overwrite a released version of libarrow you may already have installed, and so that you are also able work with more than one version of libarrow (by using different `ARROW_HOME` directories for the different versions).

In the example below, libarrow is installed to a directory called `dist` that has the same parent directory as the arrow checkout. Your installation of the Arrow R package can point to any directory with any name, though we recommend *not* placing it inside of the arrow git checkout directory as unwanted changes could stop it working properly.

```{bash, save=run & !sys_install}

_Special instructions on Linux:_ You will need to set `LD_LIBRARY_PATH` to the `lib` directory that is under where you set `$ARROW_HOME`, before launching R and using arrow. One way to do this is to add it to your profile (we use `~/.bash_profile` here, but you might need to put this in a different file depending on your setup, e.g. if you use a shell other than `bash`). On macOS you do not need to do this because the macOS shared library paths are hardcoded to their locations during build time.

```{bash, save=run & ubuntu & !sys_install}

_Special instructions on Windows:_ You will need to add `$ARROW_HOME/bin` to your `PATH` if you are using dynamic libraries (which is recommended).

```{bash, save=run & windows}

Start by navigating in a terminal to the arrow repository. You will need to create a directory into which the C++ build will put its contents. We recommend that you make a `build` directory inside of the `cpp` directory of the Arrow git repository (it is git-ignored, so you won't accidentally check it in). Next, change directories to be inside `cpp/build`:

```{bash, save=run & !sys_install}

You'll first call `cmake` to configure the build and then `make install`. For the R package, you'll need to enable several features in libarrow using `-D` flags:

```{bash, save=run & !sys_install & !windows}

```{bash, save=run & !sys_install & windows}

`..` refers to the C++ source directory: you're in `cpp/build` and the source is in `cpp`.

**For Windows**: some options, including `-DARROW_JEMALLOC`, are not supported on Windows.

```{bash, save=run & !sys_install, hide=TRUE}

To enable optional features including: S3 support, an alternative memory allocator, and additional compression libraries, add some or all of these flags to your call to `cmake` (the trailing `\` makes them easier to paste into a bash shell on a new line):

-DARROW_GCS=ON \

-DARROW_MIMALLOC=ON \

-DARROW_S3=ON \

-DARROW_WITH_BROTLI=ON \

-DARROW_WITH_BZ2=ON \

-DARROW_WITH_LZ4=ON \

-DARROW_WITH_SNAPPY=ON \

-DARROW_WITH_ZSTD=ON \

Other flags that may be useful:

* `-DBoost_SOURCE=BUNDLED` and `-DThrift_SOURCE=BUNDLED`, for example, or any other dependency `*_SOURCE`, if you have a system version of a C++ dependency that doesn't work correctly with Arrow. This tells the build to compile its own version of the dependency from source.

* `-DCMAKE_BUILD_TYPE=debug` or `-DCMAKE_BUILD_TYPE=relwithdebinfo` can be useful for debugging. You probably don't want to do this generally because a debug build is much slower at runtime than the default `release` build.

* `-DARROW_BUILD_STATIC=ON` and `-DARROW_BUILD_SHARED=OFF` if you want to use static libraries instead of dynamic libraries. With static libraries there isn't a risk of the R package linking to the wrong library, but it does mean if you change the C++ code you have to recompile both the C++ libraries and the R package. Compilers typically will link to static libraries only if the dynamic ones are not present, which is why we need to set `-DARROW_BUILD_SHARED=OFF`. If you are switching after compiling and installing previously, you may need to remove the `.dll` or `.so` files from `$ARROW_HOME/dist/bin`.

_Note_ `cmake` is particularly sensitive to whitespacing, if you see errors, check that you don't have any errant whitespace.

You can add `-j#` at the end of the command here too to speed up compilation by running in parallel (where `#` is the number of cores you have available).

```{bash, save=run & !(sys_install & ubuntu)}

Once you've built libarrow, you can install the R package and its

dependencies, along with additional dev dependencies, from the git

checkout:

```{bash, save=run}

The `--no-multiarch` flag makes it only compile on the "main" architecture. This will compile for the architecture that the R in your path corresponds to. If you compile on one architecture and then switch to another, make sure to pass the `--preclean` flag so that the R package code is recompiled for the new architecture. Otherwise, you may see errors like `LoadLibrary failure: %1 is not a valid Win32 application`.

If you need to set any compilation flags while building the C++

extensions, you can use the `ARROW_R_CXXFLAGS` environment variable. For

example, if you are using `perf` to profile the R extensions, you may

need to set

export ARROW_R_CXXFLAGS=-fno-omit-frame-pointer

With the setup described here, you should not need to rebuild the Arrow library or even the C++ source in the R package as you iterate and work on the R package. The only time those should need to be rebuilt is if you have changed the C++ in the R package (and even then, `R CMD INSTALL .` should only need to recompile the files that have changed) _or_ if the libarrow C++ has changed and there is a mismatch between libarrow and the R package. If you find yourself rebuilding either or both each time you install the package or run tests, something is probably wrong with your set up.

<details>

<summary>For a full build: a `cmake` command with all of the R-relevant optional dependencies turned on. Development with other languages might require different flags as well. For example, to develop Python, you would need to also add `-DARROW_PYTHON=ON` (though all of the other flags used for Python are already included here).</summary>

<p>

cmake \

-DCMAKE_INSTALL_PREFIX=$ARROW_HOME \

-DCMAKE_INSTALL_LIBDIR=lib \

-DARROW_COMPUTE=ON \

-DARROW_CSV=ON \

-DARROW_DATASET=ON \

-DARROW_EXTRA_ERROR_CONTEXT=ON \

-DARROW_FILESYSTEM=ON \

-DARROW_GCS=ON \

-DARROW_INSTALL_NAME_RPATH=OFF \

-DARROW_JEMALLOC=ON \

-DARROW_JSON=ON \

-DARROW_MIMALLOC=ON \

-DARROW_PARQUET=ON \

-DARROW_S3=ON \

-DARROW_WITH_BROTLI=ON \

-DARROW_WITH_BZ2=ON \

-DARROW_WITH_LZ4=ON \

-DARROW_WITH_SNAPPY=ON \

-DARROW_WITH_ZLIB=ON \

-DARROW_WITH_ZSTD=ON \

..

</p>

</details>

If you need an arrow installation from a specific repository or git reference, on most platforms except Windows, you can run:

The `build = FALSE` argument is important so that the installation can access the

C++ source in the `cpp/` directory in `apache/arrow`.

As with other installation methods, setting the environment variables `LIBARROW_MINIMAL=false` and `ARROW_R_DEV=true` will provide a more full-featured version of Arrow and provide more verbose output, respectively.

For example, to install from the (fictional) branch `bugfix` from `apache/arrow` you could run:

Sys.setenv(LIBARROW_MINIMAL="false")

remotes::install_github("apache/arrow/r@bugfix", build = FALSE)

Developers may wish to use this method of installing a specific commit

separate from another Arrow development environment or system installation

(e.g. we use this in [arrowbench](https://github.com/ursacomputing/arrowbench)

to install development versions of libarrow isolated from the system install). If

you already have libarrow installed system-wide, you may need to set

some additional variables in order to isolate this build from your system libraries:

* Setting the environment variable `FORCE_BUNDLED_BUILD` to `true` will skip the `pkg-config` search for libarrow and attempt to build from the same source at the repository+ref given.

* You may also need to set the Makevars `CPPFLAGS` and `LDFLAGS` to `""` in order to prevent the installation process from attempting to link to already installed system versions of libarrow. One way to do this temporarily is wrapping your `remotes::install_github()` call like so:

* See the user-facing [article on installation](../install.html) for a large number of

environment variables that determine how the build works and what features

get built.

* `TEST_OFFLINE_BUILD`: When set to `true`, the build script will not download

prebuilt the C++ library binary.

It will turn off any features that require a download, unless they're available

in `ARROW_THIRDPARTY_DEPENDENCY_DIR` or the `tools/thirdparty_download/` subfolder.

`create_package_with_all_dependencies()` creates that subfolder.

Regardless of this flag's value, `cmake` will be downloaded if it's unavailable.

Note that after any change to libarrow, you must reinstall it and

run `make clean` or `git clean -fdx .` to remove any cached object code

in the `r/src/` directory before reinstalling the R package. This is

only necessary if you make changes to libarrow source; you do not

need to manually purge object files if you are only editing R or C++

code inside `r/`.

If libarrow and the R package have diverged, you will see errors like:

To resolve this, try [rebuilding the Arrow library](#step-3-building-arrow).

If you are installing from a user-level directory, and you already have a

previous installation of libarrow in a system directory, you get you may get

errors like the following when you install the R package:

If this happens, you need to make sure that you don't let R link to your system

library when building arrow. You can do this a number of different ways:

* Setting the `MAKEFLAGS` environment variable to `"LDFLAGS="` (see below for an example) this is the recommended way to accomplish this

* Using {withr}'s `with_makevars(list(LDFLAGS = ""), ...)`

* adding `LDFLAGS=` to your `~/.R/Makevars` file (the least recommended way, though it is a common debugging approach suggested online)

```{bash, save=run & !sys_install & macos, hide=TRUE}

```{bash, save=run & !sys_install & ubuntu, hide=TRUE}

```{bash, save=run & !sys_install & macos}

If the package fails to install/load with an error like this:

ensure that `-DARROW_INSTALL_NAME_RPATH=OFF` was passed (this is important on

macOS to prevent problems at link time and is a no-op on other platforms).

Alternatively, try setting the environment variable `R_LD_LIBRARY_PATH` to

wherever Arrow C++ was put in `make install`, e.g. `export

R_LD_LIBRARY_PATH=/usr/local/lib`, and retry installing the R package.

When installing from source, if the R and C++ library versions do not

match, installation may fail. If you've previously installed the

libraries and want to upgrade the R package, you'll need to update the

Arrow C++ library first.

For any other build/configuration challenges, see the [C++ developer

guide](https://arrow.apache.org/docs/developers/cpp/building.html).

There are a number of scripts that are triggered when the arrow R package is installed. For package users who are not interacting with the underlying code, these should all just work without configuration and pull in the most complete pieces (e.g. official binaries that we host). However, knowing about these scripts can help package developers troubleshoot if things go wrong in them or things go wrong in an install. See [the article on R package installation](./install_details.html) for more information.