Allow nix.conf options to be set in flake.nix

This makes it possible to have per-project configuration in flake.nix,
e.g. binary caches and other stuff:

  nixConfig.bash-prompt-suffix = "ngi# ";
  nixConfig.substituters = [ "https://cache.ngi0.nixos.org/" ];
This commit is contained in:
Eelco Dolstra 2020-10-26 20:45:39 +01:00
parent 731edf0d9b
commit 343239fc8a
3 changed files with 80 additions and 6 deletions

View file

@ -71,11 +71,17 @@ static std::tuple<fetchers::Tree, FlakeRef, FlakeRef> fetchOrSubstituteTree(
return {std::move(tree), resolvedRef, lockedRef};
}
static void expectType(EvalState & state, ValueType type,
Value & value, const Pos & pos)
static void forceTrivialValue(EvalState & state, Value & value, const Pos & pos)
{
if (value.type == tThunk && value.isTrivial())
state.forceValue(value, pos);
}
static void expectType(EvalState & state, ValueType type,
Value & value, const Pos & pos)
{
forceTrivialValue(state, value, pos);
if (value.type != type)
throw Error("expected %s but got %s at %s",
showType(type), showType(value.type), pos);
@ -114,7 +120,6 @@ static FlakeInput parseFlakeInput(EvalState & state,
expectType(state, tString, *attr.value, *attr.pos);
input.follows = parseInputPath(attr.value->string.s);
} else {
state.forceValue(*attr.value);
if (attr.value->type == tString)
attrs.emplace(attr.name, attr.value->string.s);
else
@ -223,10 +228,41 @@ static Flake getFlake(
} else
throw Error("flake '%s' lacks attribute 'outputs'", lockedRef);
auto sNixConfig = state.symbols.create("nixConfig");
if (auto nixConfig = vInfo.attrs->get(sNixConfig)) {
expectType(state, tAttrs, *nixConfig->value, *nixConfig->pos);
for (auto & option : *nixConfig->value->attrs) {
forceTrivialValue(state, *option.value, *option.pos);
if (option.value->type == tString)
flake.config.options.insert({option.name, state.forceStringNoCtx(*option.value, *option.pos)});
else if (option.value->type == tInt)
flake.config.options.insert({option.name, state.forceInt(*option.value, *option.pos)});
else if (option.value->type == tBool)
flake.config.options.insert({option.name, state.forceBool(*option.value, *option.pos)});
else if (option.value->isList()) {
std::vector<std::string> ss;
for (unsigned int n = 0; n < option.value->listSize(); ++n) {
auto elem = option.value->listElems()[n];
if (elem->type != tString)
throw TypeError("list element in flake configuration option '%s' is %s while a string is expected",
option.name, showType(*option.value));
ss.push_back(state.forceStringNoCtx(*elem, *option.pos));
}
flake.config.options.insert({option.name, ss});
}
else
throw TypeError("flake configuration option '%s' is %s",
option.name, showType(*option.value));
}
}
for (auto & attr : *vInfo.attrs) {
if (attr.name != state.sDescription &&
attr.name != sInputs &&
attr.name != sOutputs)
attr.name != sOutputs &&
attr.name != sNixConfig)
throw Error("flake '%s' has an unsupported attribute '%s', at %s",
lockedRef, attr.name, *attr.pos);
}
@ -599,4 +635,30 @@ Fingerprint LockedFlake::getFingerprint() const
Flake::~Flake() { }
void ConfigFile::apply()
{
for (auto & [name, value] : options) {
// FIXME: support 'trusted-public-keys' (and other options), but make it TOFU.
if (name != "bash-prompt-suffix" &&
name != "bash-prompt" &&
name != "substituters" &&
name != "extra-substituters")
{
warn("ignoring untrusted flake configuration option '%s'", name);
continue;
}
// FIXME: Move into libutil/config.cc.
if (auto s = std::get_if<std::string>(&value))
globalConfig.set(name, *s);
else if (auto n = std::get_if<int64_t>(&value))
globalConfig.set(name, fmt("%d", n));
else if (auto b = std::get_if<Explicit<bool>>(&value))
globalConfig.set(name, b->t ? "true" : "false");
else if (auto ss = std::get_if<std::vector<std::string>>(&value))
globalConfig.set(name, concatStringsSep(" ", *ss)); // FIXME: evil
else
assert(false);
}
}
}

View file

@ -47,8 +47,16 @@ struct FlakeInput
FlakeInputs overrides;
};
// The Flake structure is the main internal representation of a flake.nix file.
struct ConfigFile
{
using ConfigValue = std::variant<std::string, int64_t, Explicit<bool>, std::vector<std::string>>;
std::map<std::string, ConfigValue> options;
void apply();
};
/* The contents of a flake.nix file. */
struct Flake
{
FlakeRef originalRef; // the original flake specification (by the user)
@ -57,6 +65,7 @@ struct Flake
std::optional<std::string> description;
std::shared_ptr<const fetchers::Tree> sourceInfo;
FlakeInputs inputs;
ConfigFile config; // 'nixConfig' attribute
~Flake();
};

View file

@ -533,8 +533,11 @@ InstallableFlake::getCursors(EvalState & state)
std::shared_ptr<flake::LockedFlake> InstallableFlake::getLockedFlake() const
{
if (!_lockedFlake)
if (!_lockedFlake) {
_lockedFlake = std::make_shared<flake::LockedFlake>(lockFlake(*state, flakeRef, lockFlags));
_lockedFlake->flake.config.apply();
// FIXME: send new config to the daemon.
}
return _lockedFlake;
}