SHA-256 outputs of fixed-output derivations. I.e. they now produce
the same store path:
$ nix-store --add x
/nix/store/j2fq9qxvvxgqymvpszhs773ncci45xsj-x
$ nix-store --add-fixed --recursive sha256 x
/nix/store/j2fq9qxvvxgqymvpszhs773ncci45xsj-x
the latter being the same as the path that a derivation
derivation {
name = "x";
outputHashAlgo = "sha256";
outputHashMode = "recursive";
outputHash = "...";
...
};
produces.
This does change the output path for such fixed-output derivations.
Fortunately they are quite rare. The most common use is fetchsvn
calls with SHA-256 hashes. (There are a handful of those is
Nixpkgs, mostly unstable development packages.)
* Documented the computation of store paths (in store-api.cc).
accessed time of paths that may be deleted. Anything more recently
used won't be deleted. The time is specified in time_t,
e.g. seconds since 1970-01-01 00:00:00 UTC; use `date +%s' to
convert to time_t from the command line.
Example: to delete everything that hasn't been used in the last two
months:
$ nix-store --gc -v --max-atime $(date +%s -d "2 months ago")
order of ascending last access time. This is useful in conjunction
with --max-freed or --max-links to prefer deleting non-recently used
garbage, which is good (especially in the build farm) since garbage
may become live again.
The code could easily be modified to accept other criteria for
ordering garbage by changing the comparison operator used by the
priority queue in collectGarbage().
bytes have been freed, `--max-links' to stop when the Nix store
directory has fewer than N hard links (the latter being important
for very large Nix stores on filesystems with a 32000 subdirectories
limit).
$ nix-env -e $(which firefox)
or
$ nix-env -e /nix/store/nywzlygrkfcgz7dfmhm5xixlx1l0m60v-pan-0.132
* nix-env -i: if an argument contains a slash anywhere, treat it as a
path and follow it through symlinks into the Nix store. This allows
things like
$ nix-build -A firefox
$ nix-env -i ./result
* nix-env -q/-i/-e: don't complain when the `*' selector doesn't match
anything. In particular, `nix-env -q \*' doesn't fail anymore on an
empty profile.
usage by finding identical files in the store and hard-linking them
to each other. It typically reduces the size of the store by
something like 25-35%. This is what the optimise-store.pl script
did, but the new command is faster and more correct (it's safe wrt
garbage collection and concurrent builds).
need any info on substitutable paths, we just call the substituters
(such as download-using-manifests.pl) directly. This means that
it's no longer necessary for nix-pull to register substitutes or for
nix-channel to clear them, which makes those operations much faster
(NIX-95). Also, we don't have to worry about keeping nix-pull
manifests (in /nix/var/nix/manifests) and the database in sync with
each other.
The downside is that there is some overhead in calling an external
program to get the substitutes info. For instance, "nix-env -qas"
takes a bit longer.
Abolishing the substitutes table also makes the logic in
local-store.cc simpler, as we don't need to store info for invalid
paths. On the downside, you cannot do things like "nix-store -qR"
on a substitutable but invalid path (but nobody did that anyway).
* Never catch interrupts (the Interrupted exception).
which paths specified on the command line are invalid (i.e., don't
barf when encountering an invalid path, just print it). This is
useful for build-remote.pl to figure out which paths need to be
copied to a remote machine. (Currently we use rsync, but that's
rather inefficient.)
--export' into the Nix store, and optionally check the cryptographic
signatures against /nix/etc/nix/signing-key.pub. (TODO: verify
against a set of public keys.)
path. This is like `nix-store --dump', only it also dumps the
meta-information of the store path (references, deriver). Will add
a `--sign' flag later to add a cryptographic signature, which we
will use for exchanging store paths between build farm machines in a
secure manner.
* nix-unpack-closure: extract the top-level paths from the closure and
print them on stdout. This allows them to be installed, e.g.,
"nix-env -i $(nix-unpack-closure)". (NIX-64)
`nix-store --delete'. But unprivileged users are not allowed to
ignore liveness.
* `nix-store --delete --ignore-liveness': ignore the runtime roots as
well.
* Some refactoring: put the NAR archive integer/string serialisation
code in a separate file so it can be reused by the worker protocol
implementation.
containing functions that operate on the Nix store. One
implementation is LocalStore, which operates on the Nix store
directly. The next step, to enable secure multi-user Nix, is to
create a different implementation RemoteStore that talks to a
privileged daemon process that uses LocalStore to perform the actual
operations.
gives a huge speedup in operations that read or write from standard
input/output. (So libstdc++'s I/O isn't that bad, you just have to
call std::ios::sync_with_stdio(false).) For instance, `nix-store
--register-substitutes' went from 1.4 seconds to 0.1 seconds on a
certain input. Another victory for Valgrind.
available. For instance,
$ nix-store -l $(which svn) | less
lets you read the build log of the Subversion instance in your
profile.
* `nix-store -qb': if applied to a non-derivation, take the deriver.
the disk is full (because to delete something from the Nix store, we
need a Berkeley DB transaction, which takes up disk space). Under
normal operation, we make sure that there exists a file
/nix/var/nix/db/reserved of 1 MB. When running the garbage
collector, we delete that file before we open the Berkeley DB
environment.
deletes a path even if it is reachable from a root. However, it
won't delete a path that still has referrers (since that would
violate store invariants).
Don't try this at home. It's a useful hack for recovering from
certain situations in a somewhat clean way (e.g., holes in closures
due to disk corruption).
nix-store query options `--referer' and `--referer-closure' have
been changed to `--referrer' and `--referrer-closure' (but the old
ones are still accepted for compatibility).
derivations. This is mostly to simplify the implementation of
nix-prefetch-{url, svn}, which now work properly in setuid
installations.
* Enforce valid store names in `nix-store --add / --add-fixed'.
of the given derivation. Useful for getting a quick overview of how
something was built. E.g., to find out how the `baffle' program in
your user environment was built, you can do
$ nix-store -q --tree $(nix-store -qd $(which baffle))
Tree nesting depth is minimised (?) by topologically sorting paths
under the relation A < B iff A \in closure(B).
user environment, e.g.,
$ nix-env -i /nix/store/z58v41v21xd3ywrqk1vmvdwlagjx7f10-aterm-2.3.1.drv
or
$ nix-env -i /nix/store/hsyj5pbn0d9iz7q0aj0fga7cpaadvp1l-aterm-2.3.1
This is useful because it allows Nix expressions to be bypassed
entirely. For instance, if only a nix-pull manifest is provided,
plus the top-level path of some component, it can be installed
without having to supply the Nix expression (e.g., for obfuscation,
or to be independent of Nix expression language changes or context
dependencies).
* Removed some dead code (successor stuff) from nix-push.
* Updated terminology in the tests (store expr -> drv path).
* Check that the deriver is set properly in the tests.
for finding build-time dependencies (possibly after a build). E.g.,
$ nix-store -qb aterm $(nix-store -qd $(which strc))
/nix/store/jw7c7s65n1gwhxpn35j9rgcci6ilzxym-aterm-2.3.1
* Arguments to nix-store can be files within store objects, e.g.,
/nix/store/jw7c...-aterm-2.3.1/bin/baffle.
* Idem for garbage collector roots.
This was necessary becase root finding must be done after
acquisition of the global GC lock.
This makes `nix-collect-garbage' obsolete; it is now just a wrapper
around `nix-store --gc'.
* Automatically remove stale GC roots (i.e., indirect GC roots that
point to non-existent paths).
get rid of GC roots. Nix-build places a symlink `result' in the
current directory. Previously, removing that symlink would not
remove the store path being linked to as a GC root. Now, the GC
root created by nix-build is actually a symlink in
`/nix/var/nix/gcroots/auto' to `result'. So if that symlink is
removed the GC root automatically becomes invalid (since it can no
longer be resolved). The root itself is not automatically removed -
the garbage collector should delete dangling roots.
immediately add the result as a permanent GC root. This is the only
way to prevent a race with the garbage collector. For instance, the
old style
ln -s $(nix-store -r $(nix-instantiate foo.nix)) \
/nix/var/nix/gcroots/result
has two time windows in which the garbage collector can interfere
(by GC'ing the derivation and the output, respectively). On the
other hand,
nix-store --add-root /nix/var/nix/gcroots/result -r \
$(nix-instantiate --add-root /nix/var/nix/gcroots/drv \
foo.nix)
is safe.
* nix-build: use `--add-root' to prevent GC races.
though). In particular it's now much easier to register a GC root.
Just place a symlink to whatever store path it is that you want to
keep in /nix/var/nix/gcroots.
This simplifies garbage collection and `nix-store --query
--requisites' since we no longer need to treat derivations
specially.
* Better maintaining of the invariants, e.g., setReferences() can only
be called on a valid/substitutable path.
closure of the referers relation rather than the references
relation, i.e., the set of all paths that directly or indirectly
refer to the given path. Note that contrary to the references
closure this set is not fixed; it can change as paths are added to
or removed from the store.
graph. That is, `nix-store --query --references PATH' shows the set
of paths referenced by PATH, and `nix-store --query --referers PATH'
shows the set of paths referencing PATH.
`derivations.cc', etc.
* Store the SHA-256 content hash of store paths in the database after
they have been built/added. This is so that we can check whether
the store has been messed with (a la `rpm --verify').
* When registering path validity, verify that the closure property
holds.
representation of closures as ATerms in the Nix store. Instead, the
file system pointer graph is now stored in the Nix database. This
has many advantages:
- It greatly simplifies the implementation (we can drop the notion
of `successors', and so on).
- It makes registering roots for the garbage collector much easier.
Instead of specifying the closure expression as a root, you can
simply specify the store path that must be retained as a root.
This could not be done previously, since there was no way to find
the closure store expression containing a given store path.
- Better traceability: it is now possible to query what paths are
referenced by a path, and what paths refer to a path.
- Drop the store expression. So now a substitute is just a
command-line invocation (a program name + arguments). If you
register a substitute you are responsible for registering the
expression that built it (if any) as a root of the garbage
collector.
- Drop the substitutes-rev DB table.
profile. Arguments are either generation number, or `old' to delete
all non-current generations. Typical use:
$ nix-env --delete-generations old
$ nix-collect-garbage
* istringstream -> string2Int.
unreachable paths that haven't been used for N hours. For instance,
`nix-collect-garbage --min-age 168' only deletes paths that haven't
been accessed in the last week.
This is useful for instance in the build farm where many derivations
can be shared between consecutive builds, and we wouldn't want a
garbage collect to throw them all away. We could of course register
them as roots, but then we'd to unregister them at some point, which
would be a pain to manage. The `--min-age' flag gives us a sort of
MRU caching scheme.
BUG: this really shouldn't be in gc.cc since that violates
mechanism/policy separation.
doesn't just print the set of paths that should be deleted. So
there is no more need to pipe the result into `nix-store --delete'
(which doesn't even exist anymore).
suboperations `--print-live', `--print-dead', and `--delete'. The
roots are not determined by nix-store; they are read from standard
input. This is to make it easy to customise what the roots are.
The collector now no longer fails when store expressions are missing
(which legally happens when using substitutes). It never tries to
fetch paths through substitutes.
TODO: acquire a global lock on the store while garbage collecting.
* Removed `nix-store --delete'.
Whenever Nix attempts to realise a derivation for which a closure is
already known, but this closure cannot be realised, fall back on
normalising the derivation.
The most common scenario in which this is useful is when we have
registered substitutes in order to perform binary distribution from,
say, a network repository. If the repository is down, the
realisation of the derivation will fail. When this option is
specified, Nix will build the derivation instead. Thus, binary
installation falls back on a source installation. This option is
not the default since it is generally not desirable for a transient
failure in obtaining the substitutes to lead to a full build from
source (with the related consumption of resources).
improve throughput.
* Don't build the `substitute-rev' table for now, since it caused
Theta(N^2) time and log file consumption when adding N substitutes.
Maybe we can do without it.
* A better substitute mechanism.
Instead of generating a store expression for each store path for
which we have a substitute, we can have a single store expression
that builds a generic program that is invoked to build the desired
store path, which is passed as an argument.
This means that operations like `nix-pull' only produce O(1) files
instead of O(N) files in the store when registering N substitutes.
(It consumes O(N) database storage, of course, but that's not a
performance problem).
* Added a test for the substitute mechanism.
* `nix-store --substitute' reads the substitutes from standard input,
instead of from the command line. This prevents us from running
into the kernel's limit on command line length.
