lix/tests/test-libstoreconsumer/main.cc
John Ericson 60b7121d2c Make the Derived Path family of types inductive for dynamic derivations
We want to be able to write down `foo.drv^bar.drv^baz`:
`foo.drv^bar.drv` is the dynamic derivation (since it is itself a
derivation output, `bar.drv` from `foo.drv`).

To that end, we create `Single{Derivation,BuiltPath}` types, that are
very similar except instead of having multiple outputs (in a set or
map), they have a single one. This is for everything to the left of the
rightmost `^`.

`NixStringContextElem` has an analogous change, and now can reuse
`SingleDerivedPath` at the top level. In fact, if we ever get rid of
`DrvDeep`, `NixStringContextElem` could be replaced with
`SingleDerivedPath` entirely!

Important note: some JSON formats have changed.

We already can *produce* dynamic derivations, but we can't refer to them
directly. Today, we can merely express building or example at the top
imperatively over time by building `foo.drv^bar.drv`, and then with a
second nix invocation doing `<result-from-first>^baz`, but this is not
declarative. The ethos of Nix of being able to write down the full plan
everything you want to do, and then execute than plan with a single
command, and for that we need the new inductive form of these types.

Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
2023-08-10 00:08:32 -04:00

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1.1 KiB
C++

#include "globals.hh"
#include "store-api.hh"
#include "build-result.hh"
#include <iostream>
using namespace nix;
int main (int argc, char **argv)
{
try {
if (argc != 2) {
std::cerr << "Usage: " << argv[0] << " store/path/to/something.drv\n";
return 1;
}
std::string drvPath = argv[1];
initLibStore();
auto store = nix::openStore();
// build the derivation
std::vector<DerivedPath> paths {
DerivedPath::Built {
.drvPath = makeConstantStorePathRef(store->parseStorePath(drvPath)),
.outputs = OutputsSpec::Names{"out"}
}
};
const auto results = store->buildPathsWithResults(paths, bmNormal, store);
for (const auto & result : results) {
for (const auto & [outputName, realisation] : result.builtOutputs) {
std::cout << store->printStorePath(realisation.outPath) << "\n";
}
}
return 0;
} catch (const std::exception & e) {
std::cerr << "Error: " << e.what() << "\n";
return 1;
}
}