direnv plugin for asdf version manager
asdf version resolution is slow which makes every command execution pay that penalty. asdf reshim
is needed for finding new executables, and some tools are not happy with their executables being masked by shims.
asdf is a great tool for managing multiple versions of command-line tools. 99% of the time these managed tools work just as expected.
Shims are just tiny wrappers created by asdf that just forward execution to the real versioned executables installed by asdf. This way, asdf has a single shims directory added to your PATH and has no need of mangling the PATH for every installed version.
When you run an asdf-managed command, like node
, it will actually execute an
asdf-shim, which will determine the node
version to activate according to your
.tool-versions
file.
A downside of this is that every single time you run node
asdf will have to
determine again which version to use. Even if you haven't changed your
.tool-versions
file to upgrade the node version to use. And this happens for
every shim execution, which could lead to some users experiencing certain
slowness while asdf is looking up versions, since it has to traverse
directories looking up for a .tool-versions file and probably also legacy
version files.
Another inconvenience is that commands installed by these tools can have some
problems by the way asdf shims work. For example, if a command tries to find
itself by name in PATH (e.g. using which my-command
) it will find the asdf
shim executable and not the actual executable delegated-to by asdf. This might
cause problems if the command tries to use this location as an installation root
to find auxiliary files, since shims will mask the real executable.
Also, people frequently ask why is reshim needed. Suppose you used asdf to
install a package manager like npm
, hex
, gem
, cargo
, etc. Any new
binaries installed by these tools won't be available on PATH unless you run
asdf reshim
. This is because asdf has no way of knowing what the npm install
command does, and it's until asdf reshim
that it will figure out new
executables are available and will create shims for them accordingly.
And finally, some packages come not only with language-specific commands, but with tons of system tools that will shadow those already installed on your system. While this may be desirable while the language is in use, having it installed and not activated leaves dead shims all over the place.
Perform asdf version resolution only once and defer environment loading to direnv.
All these previously mentioned issues can be solved by using asdf along with the direnv tool.
Just like asdf is a tools manager, direnv is an environment-variables manager. It can update your shell env upon directory change and clean it up when you leave that directory.
This asdf-direnv
plugin lets you install direnv
and also provides a tiny
script to integrate both. Allowing direnv
to manage any variables exposed by
asdf tools, primarily the PATH environment, but also any other variable exposed
by your plugin (e.g. MIX_HOME exposed by the asdf-elixir plugin).
This way, running node
will not invoke the asdf-shim but the real
asdf-managed executable in PATH. Which will improve speed since version
resolution is out of the way and made only once by direnv
upon entering your
project directory. Commands trying to find themselves in PATH will find their
expected location. Also, no more reshim needed upon npm install
.
- Make sure you have the required dependencies installed:
- curl
- git
Install this plugin and run the setup command for all of your preferred shells bash
/fish
/zsh
.
asdf plugin-add direnv
asdf direnv setup --shell bash --version latest
If you already have a direnv
installation, you can specify --version system
.
Otherwise this plugin can install it for you. Specify either --version latest
or a direnv release as shown by asdf list-all direnv
.
The setup will hint which files were modified, you might want to review its changes. After setup, close and open your terminal.
By default asdf-direnv will fail if a plugin is not installed, but is possible
to change this using the environment variable
ASDF_DIRENV_IGNORE_MISSING_PLUGINS=1
Once direnv is hooked into your system, use the asdf direnv local
command on your project root directory to update your environment.
asdf direnv local [<tool> <version>]...
Some times you just want to execute a one-shot commmand under certain
environment without creating/modifying .envrc
and .tool-versions
files
on your project directory. In those cases, you might want to try using
asdf direnv shell
.
# Enter a new shell having python and node
$ asdf direnv shell python 3.8.10 nodejs 14.18.2
# Just execute a npx command under some node version.
$ asdf direnv shell nodejs 14.18.2 -- npx create-react-app
Updating this plugin is the same as any asdf plugin:
asdf plugin update direnv
Updating the version of direnv you use depends on which installation method you've chosen:
-
system
: Nothing special required here, whenever your system package manager updates direnv, this plugin will use the updated version. -
latest
or<direnv-release-version>
: Re-runasdf direnv setup --version latest --shell ...
to update to the latest version of direnv. One may optionally add--no-touch-rc-file
to the command to prevent the shell rc file from being modified during the update.(NOTE: One may alternatively
export ASDF_DIRENV_NO_TOUCH_RC_FILE=1
to permanently prevent modification of shell rc files during updates.)
To speed up things a lot, this plugin creates direnv envrc
files that contain
your tools environment. They are created automatically whenever your .envrc
or your
.tool-versions
files change.
Cached environment files can be found under $XDG_CACHE_HOME/asdf-direnv/env
.
On most systems that resolves to ~/.config/asdf-direnv/env
. It's always safe to
remove files on this directory since they will be re-generated if missing.
If you ever need to regenerate a cached environment file, just touch .envrc
.
Also, the asdf direnv envrc
command will print the path to the cached environment
file used for your project.
Now when you leave your project directory and come back to it, direnv will manage the environment variables for you really fast. For example:
direnv: loading .envrc
direnv: using asdf
direnv: Creating env file ~/.cache/asdf-direnv/env/909519368-2773408541-1591703797-361987458
direnv: loading ~/.cache/asdf-direnv/env/909519368-2773408541-1591703797-361987458
direnv: using asdf elixir 1.8.1-otp-21
direnv: using asdf nodejs 12.6.0
direnv: export MIX_ARCHIVES MIX_HOME NPM_CONFIG_PREFIX ~PATH
with asdf-direnv:
Mean [ms] | Min [ms] | Max [ms] | Relative |
---|---|---|---|
4.3 ± 0.4 | 3.6 | 6.0 | 1.00 |
without asdf-direnv:
Mean [ms] | Min [ms] | Max [ms] | Relative |
---|---|---|---|
189.7 ± 2.7 | 185.6 | 194.0 | 1.00 |
hyperfine 'node --version'
with asdf-direnv:
Mean [ms] | Min [ms] | Max [ms] | Relative |
---|---|---|---|
683.3 ± 17.3 | 667.9 | 725.1 | 1.00 |
without asdf-direnv:
Mean [ms] | Min [ms] | Max [ms] | Relative |
---|---|---|---|
870.0 ± 12.9 | 848.4 | 894.6 | 1.00 |
hyperfine --cleanup 'npm uninstall -g yarn' 'npm install -g yarn'
-
Take a look at
direnv help true
. -
Getting
$ASDF_DIR/shims
out of the PATH.Some users might want to bypass asdf shims altogether. To do so, include only
$ASDF_DIR/bin
in your PATH but exclude the shims directory.All shims are still available via
asdf exec <shim>
# ~/.bashrc or equivalent # Don't source `~/.asdf/asdf.sh` PATH="$PATH:~/.asdf/bin"
Note: This will break any global defaults you have specified in
~/.tool-versions
. There are various workarounds for this:- Do all work in project directories with their own
.envrc
and.tool-versions
- Use
asdf direnv shell
for one-shot commands - Create a
~/.envrc
withuse asdf
in it - Use your OS's package manager to install any tools you want globally accessible
There are pros and cons to each of these approaches, it's up to you to pick the approach that works best for your workstyle.
- Do all work in project directories with their own
-
If you want to silence the console output of direnv, you can do that by setting an empty environment variable:
export DIRENV_LOG_FORMAT=""
. -
Some times you might need to configure IDEs or other tools to find executables like package managers/code linters/compilers being used on a project of yours. For example, to execute
npm
outside your project directory you can do:
direnv exec /some/project npm
-
Remember that activation order is important.
If a local
.tool-versions
file is present, the order of listed plugins will be preserved, so that toolA will be present before toolB in PATH.
# .tool-versions
toolA 1.0
toolB 2.0
-
You can
use asdf
even if current directory has no.tool-versions
file.In this case the the activated versions will be the same than those returned by
asdf current
command. -
You can override any tool version via environment variables.
See the asdf documentation regarding versions from environment variables.
# .envrc
export ASDF_PLUGIN_VERSION=1.0
use asdf
- Remember
direnv
can reload the environment whenever a file changes. By default this plugin will watch any.tool-versions
file or legacy version file that explicitly selects a tool.
But you can easily watch more files when needed.
# .envrc
watch_file "package.json"
-
Using
direnv status
can be helpful to inspect current state. Also, you might want to take a look todirenv --help
. -
Using a non-empty
ASDF_DIRENV_DEBUG
will enable bash-tracing withset -x
and skip env-cache.For example, if you are troubleshooting or trying to debug something weird on your environment, use
export ASDF_DIRENV_DEBUG=true; direnv reload
and provide any relevant output on an issue.Also, if you are contributing a new feature or bug-fix try running
env ASDF_DIRENV_DEBUG=true bats -x test
to run all tests with trace mode. If any test fails you will see more output.
Read direnv documentation for more on .envrc
.
If you are willing to contribute, be sure to read our CONTRIBUTING guide.
Licensed under the Apache License, Version 2.0.