This exploits the hermetic nature of flake evaluation to speed up
repeated evaluations of a flake output attribute.
For example (doing 'nix build' on an already present package):
$ time nix build nixpkgs:firefox
real 0m1.497s
user 0m1.160s
sys 0m0.139s
$ time nix build nixpkgs:firefox
real 0m0.052s
user 0m0.038s
sys 0m0.007s
The cache is ~/.cache/nix/eval-cache-v1.sqlite, which has entries like
INSERT INTO Attributes VALUES(
X'92a907d4efe933af2a46959b082cdff176aa5bfeb47a98fabd234809a67ab195',
'packages.firefox',
1,
'/nix/store/pbalzf8x19hckr8cwdv62rd6g0lqgc38-firefox-67.0.drv /nix/store/g6q0gx0v6xvdnizp8lrcw7c4gdkzana0-firefox-67.0 out');
where the hash 92a9... is a fingerprint over the flake store path and
the contents of the lockfile. Because flakes are evaluated in pure
mode, this uniquely identifies the evaluation result.
As long as the flake input is locked, it is now only fetched when it
is evaluated (e.g. "nixpkgs" is fetched when
"inputs.nixpkgs.<something>" is evaluated).
This required adding an "id" attribute to the members of "inputs" in
lockfiles, e.g.
"inputs": {
"nixpkgs/release-19.03": {
"id": "nixpkgs",
"inputs": {},
"narHash": "sha256-eYtxncIMFVmOHaHBtTdPGcs/AnJqKqA6tHCm0UmPYQU=",
"nonFlakeInputs": {},
"uri": "github:edolstra/nixpkgs/e9d5882bb861dc48f8d46960e7c820efdbe8f9c1"
}
}
because the flake ID needs to be known beforehand to construct the
"inputs" attrset.
Fixes#2913.
This is like 'nix run', except that the command to execute is defined
in a flake output, e.g.
defaultApp = {
type = "app";
program = "${packages.blender_2_80}/bin/blender";
};
Thus you can do
$ nix app blender-bin
to start Blender from the 'blender-bin' flake.
In the future, we can extend this with sandboxing. (For example we
would want to be able to specify that Blender should not have network
access by default and should only have access to certain paths in the
user's home directory.)
This is primarily useful for version string generation, where we need
a monotonically increasing number. The revcount is the preferred thing
to use, but isn't available for GitHub flakes (since it requires
fetching the entire history). The last commit timestamp OTOH can be
extracted from GitHub tarballs.
This ensures that flakes don't get garbage-collected, which is
important to get nix-channel-like behaviour.
For example, running
$ nix build hydra:
will create a GC root
~/.cache/nix/flake-closures/hydra -> /nix/store/xarfiqcwa4w8r4qpz1a769xxs8c3phgn-flake-closure
where the contents/references of the linked file in the store are the
flake source trees used by the 'hydra' flake:
/nix/store/n6d5f5lkpfjbmkyby0nlg8y1wbkmbc7i-source
/nix/store/vbkg4zy1qd29fnhflsv9k2j9jnbqd5m2-source
/nix/store/z46xni7d47s5wk694359mq9ay353ar94-source
Note that this in itself is not enough to allow offline use; the
fetcher for the flakeref (e.g. fetchGit or downloadCached) must not
fail if it cannot fetch the latest version of the file, so long as it
knows a cached version.
Issue #2868.
This causes 'nix' to print build log output to stderr rather than
showing the last log line in the progress bar. Log lines are prefixed
by the name of the derivation (minus the version string), e.g.
binutils> make[1]: Leaving directory '/build/binutils-2.31.1'
binutils-wrapper> unpacking sources
binutils-wrapper> patching sources
...
binutils-wrapper> Using dynamic linker: '/nix/store/kr51dlsj9v5cr4n8700jliyz8v5b2q7q-bootstrap-stage0-glibc/lib/ld-linux-x86-64.so.2'
bootstrap-stage2-gcc-wrapper> unpacking sources
...
linux-headers> unpacking sources
linux-headers> unpacking source archive /nix/store/8javli69jhj3bkql2c35gsj5vl91p382-linux-4.19.16.tar.xz
Sometimes, "expected" can be "0", but in fact means "unknown".
This is for example the case when downloading a file while the http
server doesn't send the `Content-Length` header, like when running `nix
build` pointing to a nixpkgs checkout streamed from GitHub:
⇒ nix build -f https://github.com/NixOS/nixpkgs/archive/master.tar.gz hello
[1.8/0.0 MiB DL] downloading 'https://github.com/NixOS/nixpkgs/archive/master.tar.gz'
In that case, don't show that weird progress bar, but only the (slowly
increasing) downloaded size ("done").
⇒ nix build -f https://github.com/NixOS/nixpkgs/archive/master.tar.gz hello
[1.8 MiB DL] downloading 'https://github.com/NixOS/nixpkgs/archive/master.tar.gz'
This commit also updates fmt calls with three numbers (when something is
currently 'running' too) - I'm not sure if this can be provoked, but
showing "0" as expected doesn't make any sense, as we're obviously doing
more than nothing.
Thus
$ nix dev-shell
will now build the 'provides.devShell' attribute from the flake in the
current directory. If it doesn't exist, it falls back to
'provides.defaultPackage'.
'nix dev-shell' is intended to replace nix-shell. It supports flakes,
e.g.
$ nix dev-shell nixpkgs:hello
starts a bash shell providing an environment for building 'hello'.
Like Lorri (and unlike nix-shell), it computes the build environment
by building a modified top-level derivation that writes the
environment after running $stdenv/setup to $out and exits. This
provides some caching, so it's faster than nix-shell in some cases
(especially for packages with lots of dependencies, where the setup
script takes a long time).
There also is a command 'nix print-dev-env' that prints out shell code
for setting up the build environment in an existing shell, e.g.
$ . <(nix print-dev-env nixpkgs:hello)
https://github.com/tweag/nix/issues/21
Example:
$ nix flake info dwarffs
ID: dwarffs
URI: github:edolstra/dwarffs/a83d182fe3fe528ed6366a5cec3458bcb1a5f6e1
Description: A filesystem that fetches DWARF debug info from the Internet on demand
Revision: a83d182fe3fe528ed6366a5cec3458bcb1a5f6e1
Path: /nix/store/grgd14kxxk8q4n503j87mpz48gcqpqw7-source
This ensures that the lock file is updated *before* evaluating it, and
that it gets updated for any nix command, not just 'nix build'.
Also, while computing the lock file, allow arbitrary registry lookups,
not just at top-level.
Also, improve some error messages slightly.
Also allow "." as an installable to refer to the flake in the current
directory. E.g.
$ nix build .
will build 'provides.defaultPackage' in the flake in the current
directory.
The general syntax for an installable is now
<flakeref>:<attrpath>. The attrpath is relative to the flake's
'provides.packages' or 'provides' if the former doesn't yield a
result. E.g.
$ nix build nixpkgs:hello
is equivalent to
$ nix build nixpkgs:packages.hello
Also, '<flakeref>:' can be omitted, in which case it defaults to
'nixpkgs', e.g.
$ nix build hello
This allows using an arbitrary "provides" attribute from the specified
flake. For example:
nix build --flake nixpkgs packages.hello
(Maybe provides.packages should be used for consistency...)
We want to encourage a brave new world of hermetic evaluation for
source-level reproducibility, so flakes should not poke around in the
filesystem outside of their explicit dependencies.
Note that the default installation source remains impure in that it
can refer to mutable flakes, so "nix build nixpkgs.hello" still works
(and fetches the latest nixpkgs, unless it has been pinned by the
user).
A problem with pure evaluation is that builtins.currentSystem is
unavailable. For the moment, I've hard-coded "x86_64-linux" in the
nixpkgs flake. Eventually, "system" should be a flake function
argument.
This reverts commit a0ef21262f. This
doesn't work in 'nix run' and nix-shell because setns() fails in
multithreaded programs, and Boehm GC mark threads are uncancellable.
Fixes#2646.
SRI hashes (https://www.w3.org/TR/SRI/) combine the hash algorithm and
a base-64 hash. This allows more concise and standard hash
specifications. For example, instead of
import <nix/fetchurl.nl> {
url = https://nixos.org/releases/nix/nix-2.1.3/nix-2.1.3.tar.xz;
sha256 = "5d22dad058d5c800d65a115f919da22938c50dd6ba98c5e3a183172d149840a4";
};
you can write
import <nix/fetchurl.nl> {
url = https://nixos.org/releases/nix/nix-2.1.3/nix-2.1.3.tar.xz;
hash = "sha256-XSLa0FjVyADWWhFfkZ2iKTjFDda6mMXjoYMXLRSYQKQ=";
};
In fixed-output derivations, the outputHashAlgo is no longer mandatory
if outputHash specifies the hash (either as an SRI or in the old
"<type>:<hash>" format).
'nix hash-{file,path}' now print hashes in SRI format by default. I
also reverted them to use SHA-256 by default because that's what we're
using most of the time in Nixpkgs.
Suggested by @zimbatm.
The goal is to support libeditline AND libreadline and let the user
decide at compile time which one to use.
Add a compile time option to use libreadline instead of
libeditline. If compiled against libreadline completion functionality
is lost because of a incompatibility between libeditlines and
libreadlines completion function. Completion with libreadline is
possible and can be added later.
To use libreadline instead of libeditline the environment
variables 'EDITLINE_LIBS' and 'EDITLINE_CFLAGS' have to been set
during the ./configure step.
Example:
EDITLINE_LIBS="/usr/lib/x86_64-linux-gnu/libhistory.so /usr/lib/x86_64-linux-gnu/libreadline.so"
EDITLINE_CFLAGS="-DREADLINE"
The reason for this change is that for example on Debian already three
different editline libraries exist but none of those is compatible the
flavor used by nix. My hope is that with this change it would be
easier to port nix to systems that have already libreadline available.
Calculating roots seems significantly slower on darwin compared to
linux. Checking for /profile/ links could show some false positives but
should still catch most issues.
It's pretty easy to unintentionally install a second version of nix
into the user profile when using a daemon install. In this case it
looks like nix was upgraded while the nix-daemon is probably still
unning an older version.
A protocol mismatch can sometimes cause problems when using specific
features with an older daemon. For example:
Nix 2.0 changed the way files are compied to the store. The daemon is
backwards compatible and can still handle older clients, however a 1.11
nix-daemon isn't forwards compatible.
E.g.
$ nix upgrade-nix
error: directory '/home/eelco/Dev/nix/inst/bin' does not appear to be part of a Nix profile
instead of
$ nix upgrade-nix
error: '/home/eelco/Dev/nix/inst' is not a symlink
Fix a 32-bit overflow that resulted in negative numbers being printed;
use fmt() instead of boost::format(); change -H to -h for consistency
with 'ls' and 'du'; make the columns narrower (since they can't be
bigger than 1024.0).
If the user has an object greater than 1024 yottabytes, it'll just display it as
N yottabytes instead of overflowing.
Swaps to use boost::format strings instead of std::setw and std::setprecision.
The profile present in PATH is not necessarily the actual profile
location. User profiles are generally added as $HOME/.nix-profile
in which case the indirect profile link needs to be resolved first.
/home/user/.nix-profile -> /nix/var/nix/profiles/per-user/user/profile
/nix/var/nix/profiles/per-user/user/profile -> profile-15-link
/nix/var/nix/profiles/per-user/user/profile-14-link -> /nix/store/hyi4kkjh3bwi2z3wfljrkfymz9904h62-user-environment
/nix/var/nix/profiles/per-user/user/profile-15-link -> /nix/store/6njpl3qvihz46vj911pwx7hfcvwhifl9-user-environment
To upgrade nix here we want /nix/var/nix/profiles/per-user/user/profile-16-link
instead of /home/user/.nix-profile-1-link. The latter is not a gcroot
and would be garbage collected, resulting in a broken profile.
Fixes#2175
Not ready for this yet, causes the prompt to disappear in nix repl
and more generally can overwrite non-progress-bar messages.
This reverts commit 44de71a396.
As proposed in #1634 the `nix search` command could use some
improvements. Initially 0413aeb35d added
some basic sorting behavior using `std::map`, a next step would be an
improvement of the output.
This patch includes the following changes:
* Use `$PAGER` for outputs with `RunPager` from `shared.hh`:
The same behavior is defined for `nix-env --query`, furthermore it
makes searching huge results way easier.
* Simplified result blocks:
The new output is heavily inspired by the output from `nox`, the first
line shows the attribute path and the derivaiton name
(`attribute path (derivation name)`) and the description in the second
line.
Slightly nicer behavior when updates are somewhat far apart
(during a long linking step, perhaps) ensuring things
don't appear unresponsive.
If we wait the maximum amount for the update,
don't bother waiting another 50ms (for rate-limiting purposes)
and just check if we should quit.
This also ensures we'll notice the request to quit within 1s
if quit is signalled but there is not an udpate.
(I'm not sure if this happens or not)
This makes 'nix copy' and 'nix path-info' work on .drv store
paths. Removing special treatment of .drv files seems the most
future-proof approach given the possible removal of .drv files in the
future.
Note that 'nix build' will still build (rather than substitute) .drv
paths due to the unfortunate overloading in Store::buildPaths().
EvalState contains a few counters (e.g. nrValues) that increase
quickly enough that they end up being interpreted as pointers by the
garbage collector. Moving it to the heap makes them invisible to the
garbage collector.
This reduces the max RSS doing 100 evaluations of
nixos.tests.firefox.x86_64-linux.drvPath from 455 MiB to 292 MiB.
Note: ideally, allocations would be much further up in the 64-bit
address space to reduce the odds of an integer being misinterpreted as
a pointer. Maybe we can use some linker magic to move the .bss segment
to a higher address.
Allow global config settings to be defined in multiple Config
classes. For example, this means that libutil can have settings and
evaluator settings can be moved out of libstore. The Config classes
are registered in a new GlobalConfig class to which config files
etc. are applied.
Relevant to https://github.com/NixOS/nix/issues/2009 in that it
removes the need for ad hoc handling of useCaseHack, which was the
underlying cause of that issue.
The common use case is to search for packages containing multiple words
like a "git" "frontend". Having only one expressions makes this simple regular
use case very complicated. Instead, search accepts multiple regular epressions
which all need to match.
nix search git 'gui|frontend'
returns a list of all git uis for example
This is important since this is given as an example.
Other patterns containing "empty search string" will still
be handled differently on different platforms ("asdf|")
but that's less of an issue.
nix-store --export, nix-store --dump, and nix dump-path would previously
fail silently if writing the data out failed, because
a) FdSink::write ignored exceptions, and
b) the commands relied on FdSink's destructor, which ignores
exceptions, to flush the data out.
This could cause rather opaque issues with installing nixos, because
nix-store --export would happily proceed even if it couldn't write its
data out (e.g. if nix-store --import on the other side of the pipe
failed).
This commit adds tests that expose these issues in the nix-store
commands, and fixes them for all three.
All ANSI sequences except color setting are now filtered out. In
particular, terminal resets (such as from NixOS VM tests) are filtered
out.
Also, fix the completely broken tab character handling.
This command shows why a package has another package in its runtime
closure. For example, to see why VLC has libdrm.dev in its closure:
$ nix why-depends nixpkgs.vlc nixpkgs.libdrm.dev
/nix/store/g901z9pcj0n5yy5n6ykxk3qm4ina1d6z-vlc-2.2.5.1:
lib/libvlccore.so.8.0.0: …nfig:/nix/store/405lmx6jl8lp0ad1vrr6j498chrqhz8g-libdrm-2.4.75-d…
/nix/store/s3nm7kd8hlcg0facn2q1ff2n7wrwdi2l-mesa-noglu-17.0.7-dev:
nix-support/propagated-native-build-inputs: …-dev /nix/store/405lmx6jl8lp0ad1vrr6j498chrqhz8g-libdrm-2.4.75-d…
Thus, VLC's lib/libvlccore.so.8.0.0 as well as mesa-noglu's
nix-support/propagated-native-build-inputs cause the dependency.
This is useful for testing commands in isolation.
For example,
$ nix run nixpkgs.geeqie -i -k DISPLAY -k XAUTHORITY -c geeqie
runs geeqie in an empty environment, except for $DISPLAY and
$XAUTHORITY.
E.g.
nix run nixpkgs.hello -c hello --greeting Hallo
Note that unlike "nix-shell --command", no quoting of arguments is
necessary.
"-c" (short for "--command") cannot be combined with "--" because they
both consume all remaining arguments. But since installables shouldn't
start with a dash, this is unlikely to cause problems.
Running "nix run" with a diverted store, e.g.
$ nix run --store local?root=/tmp/nix nixpkgs.hello
stopped working when Nix became multithreaded, because
unshare(CLONE_NEWUSER) doesn't work in multithreaded processes. The
obvious solution is to terminate all other threads first, but 1) there
is no way to terminate Boehm GC marker threads; and 2) it appears that
the kernel has a race where unshare(CLONE_NEWUSER) will still fail for
some indeterminate amount of time after joining other threads.
So instead, "nix run" will now exec() a single-threaded helper ("nix
__run_in_chroot") that performs the actual unshare()/chroot()/exec().
The package list is now cached in
~/.cache/nix/package-search.json. This gives a substantial speedup to
"nix search" queries. For example (on an SSD):
First run: (no package search cache, cold page cache)
$ time nix search blender
Attribute name: nixpkgs.blender
Package name: blender
Version: 2.78c
Description: 3D Creation/Animation/Publishing System
real 0m6.516s
Second run: (package search cache populated)
$ time nix search blender
Attribute name: nixpkgs.blender
Package name: blender
Version: 2.78c
Description: 3D Creation/Animation/Publishing System
real 0m0.143s
This doesn't work in read-only mode, ensuring that operations like
nix path-info --store https://cache.nixos.org -S nixpkgs.hello
(asking for the closure size of nixpkgs.hello in cache.nixos.org) work
when nixpkgs.hello doesn't exist in the local store.
On second though this was annoying. E.g. "nix log nixpkgs.hello" would
build/download Hello first, even though the log can be fetched
directly from the binary cache.
May need to revisit this.
