Commit graph

621 commits

Author SHA1 Message Date
squalus 1b595026e1 Improve durability of schema version file writes
- call close explicitly in writeFile to prevent the close exception
  from being ignored
- fsync after writing schema file to flush data to disk
- fsync schema file parent to flush metadata to disk

https://github.com/NixOS/nix/issues/7064
2022-09-19 20:13:30 -07:00
Andrew Brooks 565d888e0f Address PR feedback on #6694 2022-09-12 11:33:23 -05:00
Andrew Brooks 84fe75a12a Keep created temp dirs inside store, but protect from GC
Implements the approach suggested by feedback on PR #6994, where
tempdir paths are created in the store (now with an exclusive lock).

As part of this work, the currently-broken and unused
`createTempDirInStore` function is updated to create an exclusive lock
on the temp directory in the store.

The GC now makes a non-blocking attempt to lock any store directories
that "look like" the temp directories created by this function, and if
it can't acquire one, ignores the directory.
2022-09-06 17:48:00 -05:00
Andrew Brooks 1f041ac54f Prevent tempdir from being GC-ed before addToStoreFromDump has renamed it
This fixes issue 6823 by placing the tempdir used in LocalStore::addToStoreFromDump
outside the Nix store, where automatic GC is no longer a concern.
2022-09-02 18:32:35 -05:00
Théophane Hufschmitt 90f9680733 Only use renameFile where needed
In most places the fallback to copying isn’t needed and can actually be
bad, so we’d rather not transparently fallback
2022-08-03 10:27:25 +02:00
Théophane Hufschmitt d71d9e9fbf moveFile -> renameFile
`move` tends to have this `mv` connotation of “I will copy it for you if
needs be”
2022-08-03 10:27:25 +02:00
Théophane Hufschmitt c2de0a232c Create a wrapper around stdlib’s rename
Directly takes some c++ strings, and gently throws an exception on error
(rather than having to inline this logic everywhere)
2022-08-03 10:27:25 +02:00
Alain Zscheile 1385b20078
Get rid of most .at calls (#6393)
Use one of `get` or `getOr` instead which will either return a null-pointer (with a nicer error message) or a default value when the key is missing.
2022-05-04 07:44:32 +02:00
Sergei Trofimovich 975b0b52e7 ca: add sqlite index on RealisationsRefs(realisationReference)
Without the change any CA deletion triggers linear scan on large
RealisationsRefs table:

    sqlite>.eqp full
    sqlite> delete from RealisationsRefs where realisationReference IN ( select id from Realisations where outputPath = 1234567890 );
    QUERY PLAN
    |--SCAN RealisationsRefs
    `--LIST SUBQUERY 1
       `--SEARCH Realisations USING COVERING INDEX IndexRealisationsRefsOnOutputPath (outputPath=?)

With the change it gets turned into a lookup:

    sqlite> CREATE INDEX IndexRealisationsRefsRealisationReference on RealisationsRefs(realisationReference);
    sqlite> delete from RealisationsRefs where realisationReference IN ( select id from Realisations where outputPath = 1234567890 );
    QUERY PLAN
    |--SEARCH RealisationsRefs USING INDEX IndexRealisationsRefsRealisationReference (realisationReference=?)
    `--LIST SUBQUERY 1
       `--SEARCH Realisations USING COVERING INDEX IndexRealisationsRefsOnOutputPath (outputPath=?)
2022-04-21 10:06:39 +02:00
regnat 86d7a11c6b Make sure to delete all the realisation refs
Deleting just one will only work in the test cases where I didn’t bother
creating too many of them :p
2022-04-21 10:06:39 +02:00
regnat 92656da0b9 Fix the gc with indirect self-references via the realisations
If the derivation `foo` depends on `bar`, and they both have the same
output path (because they are CA derivations), then this output path
will depend both on the realisation of `foo` and of `bar`, which
themselves depend on each other.
This confuses SQLite which isn’t able to automatically solve this
diamond dependency scheme.

Help it by adding a trigger to delete all the references between the
relevant realisations.

Fix #5320
2022-04-21 10:06:39 +02:00
John Ericson f63b0f4540 Actually, solve this in a lighter-weight way
The templating is very superficial
2022-04-20 17:37:59 +00:00
John Ericson 05ec0beb40 Move templated functions to sqlite-impl.hh
This ensures that use-sites properly trigger new monomorphisations on
one hand, and on the other hand keeps the main `sqlite.hh` clean and
interface-only. I think that is good practice in general, but in this
situation in particular we do indeed have `sqlite.hh` users that don't
need the `throw_` function.
2022-04-20 16:57:06 +00:00
John Ericson 75b62e5260 Avoid fmt when constructor already does it
There is a correctnes issue here, but #3724 will fix that. This is just
a cleanup for brevity's sake.
2022-04-19 01:44:11 +00:00
Eelco Dolstra 5cd72598fe Add support for impure derivations
Impure derivations are derivations that can produce a different result
every time they're built. Example:

  stdenv.mkDerivation {
    name = "impure";
    __impure = true; # marks this derivation as impure
    outputHashAlgo = "sha256";
    outputHashMode = "recursive";
    buildCommand = "date > $out";
  };

Some important characteristics:

* This requires the 'impure-derivations' experimental feature.

* Impure derivations are not "cached". Thus, running "nix-build" on
  the example above multiple times will cause a rebuild every time.

* They are implemented similar to CA derivations, i.e. the output is
  moved to a content-addressed path in the store. The difference is
  that we don't register a realisation in the Nix database.

* Pure derivations are not allowed to depend on impure derivations. In
  the future fixed-output derivations will be allowed to depend on
  impure derivations, thus forming an "impurity barrier" in the
  dependency graph.

* When sandboxing is enabled, impure derivations can access the
  network in the same way as fixed-output derivations. In relaxed
  sandboxing mode, they can access the local filesystem.
2022-03-31 13:43:20 +02:00
Théophane Hufschmitt 390269ed87 Simplify the handling of the hash modulo
Rather than having four different but very similar types of hashes, make
only one, with a tag indicating whether it corresponds to a regular of
deferred derivation.

This implies a slight logical change: The original Nix+multiple-outputs
model assumed only one hash-modulo per derivation. Adding
multiple-outputs CA derivations changed this as these have one
hash-modulo per output. This change is now treating each derivation as
having one hash modulo per output.
This obviously means that we internally loose the guaranty that
all the outputs of input-addressed derivations have the same hash
modulo. But it turns out that it doesn’t matter because there’s nothing
in the code taking advantage of that fact (and it probably shouldn’t
anyways).

The upside is that it is now much easier to work with these hashes, and
we can get rid of a lot of useless `std::visit{ overloaded`.

Co-authored-by: John Ericson <John.Ericson@Obsidian.Systems>
2022-03-29 18:17:35 +02:00
John Ericson a544ed7684 Generalize DerivationType in preparation for impure derivations 2022-03-18 14:59:56 +00:00
John Ericson 197feed51d Clean up DerivationOutput, and headers
1. `DerivationOutput` now as the `std::variant` as a base class. And the
   variants are given hierarchical names under `DerivationOutput`.

   In 8e0d0689be @matthewbauer and I
   didn't know a better idiom, and so we made it a field. But this sort
   of "newtype" is anoying for literals downstream.

   Since then we leaned the base class, inherit the constructors trick,
   e.g. used in `DerivedPath`. Switching to use that makes this more
   ergonomic, and consistent.

2. `store-api.hh` and `derivations.hh` are now independent.

   In bcde5456cc I swapped the dependency,
   but I now know it is better to just keep on using incomplete types as
   much as possible for faster compilation and good separation of
   concerns.
2022-03-17 22:35:53 +00:00
John Ericson 0948b8e94d Reduce variants for derivation hash modulo
This changes was taken from dynamic derivation (#4628). It` somewhat
undoes the refactors I first did for floating CA derivations, as the
benefit of hindsight + requirements of dynamic derivations made me
reconsider some things.

They aren't to consequential, but I figured they might be good to land
first, before the more profound changes @thufschmitt has in the works.
2022-03-11 21:20:37 +00:00
Eelco Dolstra df552ff53e Remove std::string alias (for real this time)
Also use std::string_view in a few more places.
2022-02-25 16:13:02 +01:00
Eelco Dolstra 2d6d9a28eb addToStoreFromDump(): Take std::string_view 2022-02-16 11:02:35 +01:00
Eelco Dolstra 35dbdbedd4 nix store ping: Report Nix daemon version
Fixes #5952.
2022-01-25 21:15:58 +01:00
Eelco Dolstra 4dda1f92aa Add command 'nix store copy-log'
Fixes #5222.
2022-01-18 14:08:49 +01:00
Eelco Dolstra d62a9390fc Get rid of std::shared_ptr<std::string> and ref<std::string>
These were needed back in the pre-C++11 era because we didn't have
move semantics. But now we do.
2022-01-18 11:12:30 +01:00
Guillaume Maudoux e9a4abdb5d Make --repair-path also repair corrupt optimised links
There already existed a smoke test for the link content length,
but it appears that there exists some corruptions pernicious enough
to replace the file content with zeros, and keeping the same length.

--repair-path now goes as far as checking the content of the link,
making it true to its name and actually repairing the path for such
coruption cases.
2022-01-11 11:57:45 +01:00
Théophane Hufschmitt 3fc8042f77
Merge pull request #5366 from trofi/speedup-ca-query
ca-specific-schema.sql: add index on RealisationsRefs(referrer)
2021-12-14 09:08:17 +01:00
Eelco Dolstra f9437b4f18 Merge branch 'master' of https://github.com/MagicRB/nix 2021-12-10 14:49:25 +01:00
John Ericson 2f5c913d4a Fix #5299
No matter what, we need to resize the buffer to not have any scratch
space after we do the `read`. In the end of file case, `got` will be 0
from it's initial value.

Before, we forgot to resize in the EOF case with the break. Yes, we know
we didn't recieve any data in that case, but we still have the scatch
space to undo.

Co-Authored-By: Will Fancher <Will.Fancher@Obsidian.Systems>
2021-11-30 22:11:46 +00:00
Eelco Dolstra 6463eaca14
Merge pull request #5472 from NixOS/async-realisation-substitution
async realisation substitution
2021-11-16 12:54:20 +01:00
Sergei Trofimovich edfc5b2f12 ca-specific-schema.sql: add index on RealisationsRefs(referrer) and (outputPath)
For a typical desktop system (~2K packages) we can easily get 100K
entries in RealisationsRefs. Without indices query for RealisationsRefs
requires linear scan.

RealisationsRefs(referrer)
--------------------------

Inefficiency is seen as a 100% CPU load of nix-daemon for the following
scenario:

    $ nix edit -f . bash # add unused environment variable, like FOO="1"
    # populate RealisationsRefs, build fresh system
    $ nix build -f nixos system --arg config '{ contentAddressedByDefault = true; }'
    $ nix edit -f . bash # add unused environment variable, like FOO="2"
    $ time nix build -f nixos system --arg config '{ contentAddressedByDefault = true; }'

In this case `bash `will be rebuilt a few times and then rest of CPU
time is spent on scanning RealisationsRefs table (about 5 CPU-minutes
on my machine).

Before the change:

    $ time nix build -f nixos system ... # step 4 above
    real    34m3,613s
    user    0m5,232s
    sys     0m0,758s

Of all this time about 29.5 minutes are taken by nix-daemon's CPU time.

After the change:

    $ time nix build -f nixos system ... # step 4 above
    real    4m50,061s
    user    0m5,038s
    sys     0m0,677s

Of all this time about 1 minute is taken by nix-daemon's CPU time.
Most of the time is spent polling for non-existent realisations on
cache-nixos.org.

Realisations(outputPath)
------------------------

After running CA system for two weeks I got ~1M entries in Realisations
table. `nix-collect-garbage` became very slow (seemingly 100 path deletions
per second). It happens due to a slow cascading delete from Realisations
triggered by deletion from ValidPaths.

The fix is to add an index on primary key from ValidPaths(id) that
triggers cascading deletions.

Before the change:
    $ time nix-collect-garbage -d --max-freed 100G
    <interrupted before finish, took too long>
    real    23m32.411s
    user    17m49.679s
    sys     4m50.609s

Most of time was spent in re-scanning Realisations table on each path deletion.

After the change:
    $ time nix-collect-garbage -d --max-freed 100G

    real    8m43.226s
    user    6m16.317s
    sys     1m40.188s

Time is spent scanning sqlite indices and in kernel when unlinking directories.
2021-11-10 08:32:05 +00:00
Eelco Dolstra 67179472df
Merge pull request #5494 from tweag/balsoft/allow-references-in-addPath
Allow references in addPath
2021-11-09 15:57:39 +01:00
Alexander Bantyev 0b005bc9d6
addToStore, addToStoreFromDump: refactor: pass refs by const reference
Co-Authored-By: Eelco Dolstra <edolstra@gmail.com>
2021-11-09 12:24:49 +03:00
Eelco Dolstra ff2af4d64e Unshare mount namespace in main()
Doing it as a side-effect of calling LocalStore::makeStoreWritable()
is very ugly.

Also, make sure that stopping the progress bar joins the update
thread, otherwise that thread should be unshared as well.
2021-11-08 22:00:45 +01:00
Eelco Dolstra 7a71621b7c Merge branch 'fix-writable-shell' of https://github.com/yorickvP/nix 2021-11-08 21:12:51 +01:00
Alexander Bantyev 9d4dcff37a
addPath: allow paths with references
Since 4806f2f6b0, we can't have paths with
references passed to builtins.{path,filterSource}. This prevents many cases
of those functions called on IFD outputs from working. Resolve this by
passing the references found in the original path to the added path.
2021-11-05 22:41:30 +03:00
regnat 96670ed216 Expose an async interface for queryRealisation
Doesn’t change much so far because everything is still using it
synchronously, but should allow the binary cache to fetch stuff in
parallel
2021-11-03 06:51:34 +01:00
Eelco Dolstra a7d4f3411e Merge remote-tracking branch 'origin/master' into non-blocking-gc 2021-10-28 14:56:55 +02:00
regnat af99941279 Make experimental-features a proper type
Rather than having them plain strings scattered through the whole
codebase, create an enum containing all the known experimental features.

This means that
- Nix can now `warn` when an unkwown experimental feature is passed
  (making it much nicer to spot typos and spot deprecated features)
- It’s now easy to remove a feature altogether (once the feature isn’t
  experimental anymore or is dropped) by just removing the field for the
  enum and letting the compiler point us to all the now invalid usages
  of it.
2021-10-26 07:02:31 +02:00
Alexander Bantyev b9234142f5
addToStore, addToStoreFromDump: add references argument
Allow to pass a set of references to be added as info to the added paths.
2021-10-23 21:30:51 +03:00
Yorick fcb8af550f
Restore parent mount namespace in restoreProcessContext
This ensures any started processes can't write to /nix/store (except
during builds). This partially reverts 01d07b1e, which happened because
of #2646.

The problem was only happening after nix downloads anything, causing
me to suspect the download thread. The problem turns out to be:
"A  process  can't  join a new mount namespace if it is sharing
filesystem-related attributes with another process", in this case this
process is the curl thread.

Ideally, we might kill it before spawning the shell process, but it's
inside a static variable in the getFileTransfer() function. So
instead, stop it from sharing FS state using unshare(). A strategy
such as the one from #5057 (single-threaded chroot helper binary) is
also very much on the table.

Fixes #4337.
2021-10-15 16:25:49 +02:00
Eelco Dolstra 0be8cc1466 pathInfoCache: Use the entire base name as the cache key
This fixes a bug in the garbage collector where if a path
/nix/store/abcd-foo is valid, but we do a
isValidPath("/nix/store/abcd-foo.lock") first, then a negative entry
for /nix/store/abcd is added to pathInfoCache, so /nix/store/abcd-foo
is subsequently considered invalid and deleted.
2021-10-14 13:28:22 +02:00
Eelco Dolstra ff453b06f9 Fix auto-gc 2021-10-13 12:12:44 +02:00
Eelco Dolstra 8614cf1334 Non-blocking garbage collector
The garbage collector no longer blocks other processes from
adding/building store paths or adding GC roots. To prevent the
collector from deleting store paths just added by another process,
processes need to connect to the garbage collector via a Unix domain
socket to register new temporary roots.
2021-10-13 12:12:44 +02:00
Eelco Dolstra 8eac7dfad4 Remove trash directory 2021-10-13 12:12:44 +02:00
John Ericson 242f9bf3dc std::visit by reference
I had started the trend of doing `std::visit` by value (because a type
error once mislead me into thinking that was the only form that
existed). While the optomizer in principle should be able to deal with
extra coppying or extra indirection once the lambdas inlined, sticking
with by reference is the conventional default. I hope this might even
improve performance.
2021-09-30 21:35:09 +00:00
Eelco Dolstra 761ac9d584 Remove the 'ca-references' feature check
Fixes #3422.
Fixes #4425.
2021-09-14 13:53:20 +02:00
Eelco Dolstra f73d911628 Style 2021-09-01 21:46:25 +02:00
Magic_RB 8438114399
Add ignored_acls setting
Signed-off-by: Magic_RB <magic_rb@redalder.org>
2021-08-14 21:46:09 +02:00
Sebastian Ullrich 12f50b6510 Short-circuit querying substituters on success 2021-08-08 13:24:13 +02:00
regnat a4ec6cb1da Be more lenient when realisations have a conflicting dependency set
- This can legitimately happen (for example because of a non-determinism
  causing a build-time dependency to be kept or not as a runtime
  reference)
- Because of older Nix versions, it can happen that we encounter a
  realisation with an (erroneously) empty set of dependencies, in which
  case we don’t want to fail, but just warn the user and try to fix it.
2021-07-16 11:48:41 +02:00