While trying to figure out how `nix-env`/`nix profile` work I had a hard
time understand how man pages were being installed.
Took me quite some time to figure this out, thought it might be useful
to others too!
A few notes:
* The `echo hi` is needed to make sure that a file that can be read by
`nix log` is properly created (i.e. some output is needed). This is
known and to be fixed in #6051.
* We explicitly ignore the floating-CA case here: the `$out` of `input3`
depends on `$out` of `input2`. This means that there are actually two
derivations - I assume that this is because at eval time (i.e.
`nix-instantiate -A`) the hash of `input2` isn't known yet and the
other .drv is created as soon as `input2` was built. This is another
issue on its own, so we ignore the case here explicitly.
To avoid that JSON messages are parsed twice in case of
remote builds with `ssh-ng://`, I split up the original
`handleJSONLogMessage` into three parts:
* `parseJSONMessage(const std::string&)` checks if it's a message in the
form of `@nix {...}` and tries to parse it (and prints an error if the
parsing fails).
* `handleJSONLogMessage(nlohmann::json&, ...)` reads the fields from the
message and passes them to the logger.
* `handleJSONLogMessage(const std::string&, ...)` behaves as before, but
uses the two functions mentioned above as implementation.
In case of `ssh-ng://`-logs the first two methods are invoked manually.
Right now when building a derivation remotely via
$ nix build -j0 -f . hello -L --builders 'ssh://builder'
it's possible later to read through the entire build-log by running
`nix log -f . hello`. This isn't possible however when using `ssh-ng`
rather than `ssh`.
The reason for that is that there are two different ways to transfer
logs in Nix through e.g. an SSH tunnel (that are used by `ssh`/`ssh-ng`
respectively):
* `ssh://` receives its logs from the fd pointing to `builderOut`. This
is directly passed to the "log-sink" (and to the logger on each `\n`),
hence `nix log` works here.
* `ssh-ng://` however expects JSON-like messages (i.e. `@nix {log data
in here}`) and passes it directly to the logger without doing anything
with the `logSink`. However it's certainly possible to extract
log-lines from this format as these have their own message-type in the
JSON payload (i.e. `resBuildLogLine`).
This is basically what I changed in this patch: if the code-path for
`builderOut` is not reached and a `logSink` is initialized, the
message was successfully processed by the JSON logger (i.e. it's in
the expected format) and the line is of the expected type (i.e.
`resBuildLogLine`), the line will be written to the log-sink as well.
Closes#5079
Allows completing `nix build ~/flake#<Tab>`.
We can implement expansion for `~user` later if needed.
Not using wordexp(3) since that expands way too much.
Fixes#6122, which reports a problem with trying to run the installer
under another user (probably: user is not the disk "owner" and thus
can't mount the volume).
This also makes sure that we get the Docker images from the same Hydra
eval, rather than the latest build from job/nix/.../dockerImage, which
may not be the same.
On Nix 2.6 the output of `nix why-depends --all` seems to be somewhat
off:
$ nix why-depends /nix/store/kn47hayxab8gc01jhr98dwyywbx561aq-nixos-system-roflmayr-21.11.20220207.6c202a9.drv /nix/store/srn5jbs1q30jpybdmxqrwskyny659qgc-nix-2.6.drv --derivation --extra-experimental-features nix-command --all
/nix/store/kn47hayxab8gc01jhr98dwyywbx561aq-nixos-system-roflmayr-21.11.20220207.6c202a9.drv
└───/nix/store/g8bpgfjhh5vxrdq0w6r6s64f9kkm9z6c-etc.drv
│ └───/nix/store/hm0jmhp8shbf3cl846a685nv4f5cp3fy-nspawn-inst.drv
| [...]
└───/nix/store/2d6q3ygiim9ijl5d4h0qqx6vnjgxywyr-system-units.drv
└───/nix/store/dil014y1b8qyjhhhf5fpaah5fzdf0bzs-unit-systemd-nspawn-hydra.service.drv
└───/nix/store/a9r72wwx8qrxyp7hjydyg0gsrwnn26zb-activate.drv
└───/nix/store/99hlc7i4gl77wq087lbhag4hkf3kvssj-nixos-system-hydra-21.11pre-git.drv
Please note that `[...]-system-units.drv` is supposed to be a direct
child of `[...]-etc.drv`.
The reason for that is that each new level printed by `printNode` is
four spaces off in comparison to `nix why-depends --precise` because the
recursive `printNode()` only prints the path and not the `tree*`-chars in
the case of `--precise` and in this format the path is four spaces further
indented, i.e. on a newline, but on the same level as the path's children, i.e.
/nix/store/kn47hayxab8gc01jhr98dwyywbx561aq-nixos-system-roflmayr-21.11.20220207.6c202a9.drv
└───/: …1-p8.drv",["out"]),("/nix/store/g8bpgfjhh5vxrdq0w6r6s64f9kkm9z6c-etc.drv",["out"]),("/nix/store/…
→ /nix/store/g8bpgfjhh5vxrdq0w6r6s64f9kkm9z6c-etc.drv
As you can see `[...]-etc.drv` is a direct child of the root, but four
spaces indented. This logic was directly applied to the code-path with
`precise=false` which resulted in `tree*` being printed four spaces too
deep.
In case of no `--precise`, `hits[hash]` is empty and the path itself
should be printed rather than hits using the same logic as for `hits[hash]`.
With this fix, the output looks correct now:
/nix/store/kn47hayxab8gc01jhr98dwyywbx561aq-nixos-system-roflmayr-21.11.20220207.6c202a9.drv
└───/nix/store/g8bpgfjhh5vxrdq0w6r6s64f9kkm9z6c-etc.drv
├───/nix/store/hm0jmhp8shbf3cl846a685nv4f5cp3fy-nspawn-inst.drv
| [...]
└───/nix/store/2d6q3ygiim9ijl5d4h0qqx6vnjgxywyr-system-units.drv
└───/nix/store/dil014y1b8qyjhhhf5fpaah5fzdf0bzs-unit-systemd-nspawn-hydra.service.drv
└───/nix/store/a9r72wwx8qrxyp7hjydyg0gsrwnn26zb-activate.drv
└───/nix/store/99hlc7i4gl77wq087lbhag4hkf3kvssj-nixos-system-hydra-21.11pre-git.drv
It's a second attempt to merge the change. Previous attempt
was reverted in b976b34a5b.
Since then underlying failure exposed by original change was
fixed by https://github.com/NixOS/nix/pull/5354.
Below goes description of original change:
The link failure happens on a system with stable nix-2.3.15
installed in /usr/lib64 (it's libutil.so API differs from master):
```
LANG=C make V=1
g++ -o /home/slyfox/dev/git/nix/src/libstore/libnixstore.so \
-shared -L/usr/lib64 -Wl,--no-copy-dt-needed-entries \
src/libstore/binary-cache-store.o ... src/libstore/uds-remote-store.o \
-lsqlite3 -lcurl -lsodium -pthread -ldl -lseccomp -Wl,-z,defs -Wl,-soname=libnixstore.so
-Wl,-rpath,/home/slyfox/dev/git/nix/src/libutil -Lsrc/libutil -lnixutil
ld: src/libstore/binary-cache-store.o: in function `nix::BinaryCacheStore::BinaryCacheStore(
std::map<std::__cxx11::basic_string<char, std::char_traits<char>, ...
nix/src/libstore/binary-cache-store.cc:30: undefined reference to `nix::readFile(
std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)' ...
...
```
This happens due to `-L/usr/lib64 -Lsrc/libutil` search path ordering.
The change turns it into `-Lsrc/libutil -L/usr/lib64`.
Closes: https://github.com/NixOS/nix/issues/3087
