The typical use is to inherit Config and add Setting<T> members:
class MyClass : private Config
{
Setting<int> foo{this, 123, "foo", "the number of foos to use"};
Setting<std::string> bar{this, "blabla", "bar", "the name of the bar"};
MyClass() : Config(readConfigFile("/etc/my-app.conf"))
{
std::cout << foo << "\n"; // will print 123 unless overriden
}
};
Currently, this is used by Store and its subclasses for store
parameters. You now get a warning if you specify a non-existant store
parameter in a store URI.
This provides a significant speedup, e.g. 64 s -> 12 s for
nix-build --dry-run -I nixpkgs=channel:nixos-16.03 '<nixpkgs/nixos/tests/misc.nix>' -A test
on a cold local and CloudFront cache.
The alternative is to use lots of concurrent daemon connections but
that seems wasteful.
This is useless because the client also caches path info, and can
cause problems for long-running clients like hydra-queue-runner
(i.e. it may return cached info about paths that have been
garbage-collected).
This allows various Store implementations to provide different ways to
get build logs. For example, BinaryCacheStore can get the build logs
from the binary cache.
Also, remove the log-servers option since we can use substituters for
this.
... and use this in Downloader::downloadCached(). This fixes
$ nix-build https://nixos.org/channels/nixos-16.09-small/nixexprs.tar.xz -A hello
error: cannot import path ‘/nix/store/csfbp1s60dkgmk9f8g0zk0mwb7hzgabd-nixexprs.tar.xz’ because it lacks a valid signature
This writes info about every path in the closure in the same format as
‘nix path-info --json’. Thus it also includes NAR hashes and sizes.
Example:
[
{
"path": "/nix/store/10h6li26i7g6z3mdpvra09yyf10mmzdr-hello-2.10",
"narHash": "sha256:0ckdc4z20kkmpqdilx0wl6cricxv90lh85xpv2qljppcmz6vzcxl",
"narSize": 197648,
"references": [
"/nix/store/10h6li26i7g6z3mdpvra09yyf10mmzdr-hello-2.10",
"/nix/store/27binbdy296qvjycdgr1535v8872vz3z-glibc-2.24"
],
"closureSize": 20939776
},
{
"path": "/nix/store/27binbdy296qvjycdgr1535v8872vz3z-glibc-2.24",
"narHash": "sha256:1nfn3m3p98y1c0kd0brp80dn9n5mycwgrk183j17rajya0h7gax3",
"narSize": 20742128,
"references": [
"/nix/store/27binbdy296qvjycdgr1535v8872vz3z-glibc-2.24"
],
"closureSize": 20742128
}
]
Fixes#1134.
That is, when build-repeat > 0, and the output of two rounds differ,
then print a warning rather than fail the build. This is primarily to
let Hydra check reproducibility of all packages.
The removal of CachedFailure caused the value of TimedOut to change,
which broke timed-out handling in Hydra (so timed-out builds would
show up as "aborted" and would be retried, e.g. at
http://hydra.nixos.org/build/42537427).
The store parameter "write-nar-listing=1" will cause BinaryCacheStore
to write a file ‘<store-hash>.ls.xz’ for each ‘<store-hash>.narinfo’
added to the binary cache. This file contains an XZ-compressed JSON
file describing the contents of the NAR, excluding the contents of
regular files.
E.g.
{
"version": 1,
"root": {
"type": "directory",
"entries": {
"lib": {
"type": "directory",
"entries": {
"Mcrt1.o": {
"type": "regular",
"size": 1288
},
"Scrt1.o": {
"type": "regular",
"size": 3920
},
}
}
}
...
}
}
(The actual file has no indentation.)
This is intended to speed up the NixOS channels programs index
generator [1], since fetching gazillions of large NARs from
cache.nixos.org is currently a bottleneck for updating the regular
(non-small) channel.
[1] https://github.com/NixOS/nixos-channel-scripts/blob/master/generate-programs-index.cc
The fact that queryPathInfo() is synchronous meant that we needed a
thread for every concurrent binary cache lookup, even though they end
up being handled by the same download thread. Requiring hundreds of
threads is not a good idea. So now there is an asynchronous version of
queryPathInfo() that takes a callback function to process the
result. Similarly, enqueueDownload() now takes a callback rather than
returning a future.
Thus, a command like
nix path-info --store https://cache.nixos.org/ -r /nix/store/slljrzwmpygy1daay14kjszsr9xix063-nixos-16.09beta231.dccf8c5
that returns 4941 paths now takes 1.87s using only 2 threads (the main
thread and the downloader thread). (This is with a prewarmed
CloudFront.)
This makes it easier to create a diverted store, i.e.
NIX_REMOTE="local?root=/tmp/root"
instead of
NIX_REMOTE="local?real=/tmp/root/nix/store&state=/tmp/root/nix/var/nix" NIX_LOG_DIR=/tmp/root/nix/var/log
This allows an unprivileged user to perform builds on a diverted store
(i.e. where the physical store location differs from the logical
location).
Example:
$ NIX_LOG_DIR=/tmp/log NIX_REMOTE="local?real=/tmp/store&state=/tmp/var" nix-build -E \
'with import <nixpkgs> {}; runCommand "foo" { buildInputs = [procps nettools]; } "id; ps; ifconfig; echo $out > $out"'
will do a build in the Nix store physically in /tmp/store but
logically in /nix/store (and thus using substituters for the latter).
