lix/src/libexpr/primops/flake.cc
2019-04-09 09:51:42 +02:00

486 lines
16 KiB
C++

#include "flake.hh"
#include "primops.hh"
#include "eval-inline.hh"
#include "fetchGit.hh"
#include "download.hh"
#include "args.hh"
#include <iostream>
#include <queue>
#include <regex>
#include <nlohmann/json.hpp>
namespace nix {
/* Read the registry or a lock file. (Currently they have an identical
format. */
std::shared_ptr<FlakeRegistry> readRegistry(const Path & path)
{
auto registry = std::make_shared<FlakeRegistry>();
if (!pathExists(path))
return std::make_shared<FlakeRegistry>();
auto json = nlohmann::json::parse(readFile(path));
auto version = json.value("version", 0);
if (version != 1)
throw Error("flake registry '%s' has unsupported version %d", path, version);
auto flakes = json["flakes"];
for (auto i = flakes.begin(); i != flakes.end(); ++i) {
FlakeRegistry::Entry entry{FlakeRef(i->value("uri", ""))};
registry->entries.emplace(i.key(), entry);
}
return registry;
}
/* Write the registry or lock file to a file. */
void writeRegistry(FlakeRegistry registry, Path path)
{
nlohmann::json json;
json["version"] = 1;
for (auto elem : registry.entries) {
json["flakes"][elem.first] = { {"uri", elem.second.ref.to_string()} };
}
createDirs(dirOf(path));
writeFile(path, json.dump(4)); // The '4' is the number of spaces used in the indentation in the json file.
}
LockFile::FlakeEntry readFlakeEntry(nlohmann::json json)
{
FlakeRef flakeRef(json["uri"]);
if (!flakeRef.isImmutable())
throw Error("requested to fetch FlakeRef '%s' purely, which is mutable", flakeRef.to_string());
LockFile::FlakeEntry entry(flakeRef);
auto nonFlakeRequires = json["nonFlakeRequires"];
for (auto i = nonFlakeRequires.begin(); i != nonFlakeRequires.end(); ++i) {
FlakeRef flakeRef(i->value("uri", ""));
if (!flakeRef.isImmutable())
throw Error("requested to fetch FlakeRef '%s' purely, which is mutable", flakeRef.to_string());
entry.nonFlakeEntries.insert_or_assign(i.key(), flakeRef);
}
auto requires = json["requires"];
for (auto i = requires.begin(); i != requires.end(); ++i)
entry.flakeEntries.insert_or_assign(i.key(), readFlakeEntry(*i));
return entry;
}
LockFile readLockFile(const Path & path)
{
LockFile lockFile;
if (!pathExists(path))
return lockFile;
auto json = nlohmann::json::parse(readFile(path));
auto version = json.value("version", 0);
if (version != 1)
throw Error("lock file '%s' has unsupported version %d", path, version);
auto nonFlakeRequires = json["nonFlakeRequires"];
for (auto i = nonFlakeRequires.begin(); i != nonFlakeRequires.end(); ++i) {
FlakeRef flakeRef(i->value("uri", ""));
if (!flakeRef.isImmutable())
throw Error("requested to fetch FlakeRef '%s' purely, which is mutable", flakeRef.to_string());
lockFile.nonFlakeEntries.insert_or_assign(i.key(), flakeRef);
}
auto requires = json["requires"];
for (auto i = requires.begin(); i != requires.end(); ++i)
lockFile.flakeEntries.insert_or_assign(i.key(), readFlakeEntry(*i));
return lockFile;
}
nlohmann::json flakeEntryToJson(LockFile::FlakeEntry & entry)
{
nlohmann::json json;
json["uri"] = entry.ref.to_string();
for (auto & x : entry.nonFlakeEntries)
json["nonFlakeRequires"][x.first]["uri"] = x.second.to_string();
for (auto & x : entry.flakeEntries)
json["requires"][x.first] = flakeEntryToJson(x.second);
return json;
}
void writeLockFile(LockFile lockFile, Path path)
{
nlohmann::json json;
json["version"] = 1;
json["nonFlakeRequires"];
for (auto & x : lockFile.nonFlakeEntries)
json["nonFlakeRequires"][x.first]["uri"] = x.second.to_string();
for (auto & x : lockFile.flakeEntries)
json["requires"][x.first] = flakeEntryToJson(x.second);
createDirs(dirOf(path));
writeFile(path, json.dump(4)); // '4' = indentation in json file
}
Path getUserRegistryPath()
{
return getHome() + "/.config/nix/registry.json";
}
std::shared_ptr<FlakeRegistry> getGlobalRegistry()
{
// FIXME: get from nixos.org.
Path registryFile = settings.nixDataDir + "/nix/flake-registry.json";
return readRegistry(registryFile);
}
std::shared_ptr<FlakeRegistry> getUserRegistry()
{
return readRegistry(getUserRegistryPath());
}
std::shared_ptr<FlakeRegistry> getFlagRegistry()
{
return std::make_shared<FlakeRegistry>();
// TODO: Implement this once the right flags are implemented.
}
const std::vector<std::shared_ptr<FlakeRegistry>> EvalState::getFlakeRegistries()
{
std::vector<std::shared_ptr<FlakeRegistry>> registries;
if (evalSettings.pureEval) {
registries.push_back(std::make_shared<FlakeRegistry>()); // global
registries.push_back(std::make_shared<FlakeRegistry>()); // user
registries.push_back(std::make_shared<FlakeRegistry>()); // local
} else {
registries.push_back(getGlobalRegistry());
registries.push_back(getUserRegistry());
registries.push_back(getLocalRegistry());
}
registries.push_back(getFlagRegistry());
return registries;
}
// Creates a Nix attribute set value listing all dependencies, so they can be used in `provides`.
Value * makeFlakeRegistryValue(EvalState & state)
{
auto v = state.allocValue();
auto registries = state.getFlakeRegistries();
int size = 0;
for (auto registry : registries)
size += registry->entries.size();
state.mkAttrs(*v, size);
for (auto & registry : registries) {
for (auto & entry : registry->entries) {
auto vEntry = state.allocAttr(*v, entry.first);
state.mkAttrs(*vEntry, 2);
mkString(*state.allocAttr(*vEntry, state.symbols.create("uri")), entry.second.ref.to_string());
vEntry->attrs->sort();
}
}
v->attrs->sort();
return v;
}
static FlakeRef lookupFlake(EvalState & state, const FlakeRef & flakeRef,
std::vector<std::shared_ptr<FlakeRegistry>> registries)
{
if (auto refData = std::get_if<FlakeRef::IsFlakeId>(&flakeRef.data)) {
for (auto registry : registries) {
auto i = registry->entries.find(refData->id);
if (i != registry->entries.end()) {
auto newRef = FlakeRef(i->second.ref);
if (!newRef.isDirect())
throw Error("found indirect flake URI '%s' in the flake registry", i->second.ref.to_string());
if (refData->ref)
newRef.setRef(*refData->ref);
if (refData->rev)
newRef.setRev(*refData->rev);
return newRef;
}
}
throw Error("cannot find flake '%s' in the flake registry or in the flake lock file", refData->id);
} else
return flakeRef;
}
struct FlakeSourceInfo
{
Path storePath;
std::optional<Hash> rev;
std::optional<uint64_t> revCount;
};
static FlakeSourceInfo fetchFlake(EvalState & state, const FlakeRef & flakeRef, bool impureIsAllowed = false)
{
FlakeRef directFlakeRef = lookupFlake(state, flakeRef, state.getFlakeRegistries());
if (auto refData = std::get_if<FlakeRef::IsGitHub>(&directFlakeRef.data)) {
if (evalSettings.pureEval && !impureIsAllowed && !directFlakeRef.isImmutable())
throw Error("requested to fetch FlakeRef '%s' purely, which is mutable", directFlakeRef.to_string());
// FIXME: use regular /archive URLs instead? api.github.com
// might have stricter rate limits.
// FIXME: support passing auth tokens for private repos.
auto url = fmt("https://api.github.com/repos/%s/%s/tarball/%s",
refData->owner, refData->repo,
refData->rev
? refData->rev->to_string(Base16, false)
: refData->ref
? *refData->ref
: "master");
auto result = getDownloader()->downloadCached(state.store, url, true, "source",
Hash(), nullptr, refData->rev ? 1000000000 : settings.tarballTtl);
if (!result.etag)
throw Error("did not receive an ETag header from '%s'", url);
if (result.etag->size() != 42 || (*result.etag)[0] != '"' || (*result.etag)[41] != '"')
throw Error("ETag header '%s' from '%s' is not a Git revision", *result.etag, url);
FlakeSourceInfo info;
info.storePath = result.path;
info.rev = Hash(std::string(*result.etag, 1, result.etag->size() - 2), htSHA1);
return info;
}
else if (auto refData = std::get_if<FlakeRef::IsGit>(&directFlakeRef.data)) {
auto gitInfo = exportGit(state.store, refData->uri, refData->ref,
refData->rev ? refData->rev->to_string(Base16, false) : "", "source");
FlakeSourceInfo info;
info.storePath = gitInfo.storePath;
info.rev = Hash(gitInfo.rev, htSHA1);
info.revCount = gitInfo.revCount;
return info;
}
else if (auto refData = std::get_if<FlakeRef::IsPath>(&directFlakeRef.data)) {
if (!pathExists(refData->path + "/.git"))
throw Error("flake '%s' does not reference a Git repository", refData->path);
auto gitInfo = exportGit(state.store, refData->path, {}, "", "source");
FlakeSourceInfo info;
info.storePath = gitInfo.storePath;
info.rev = Hash(gitInfo.rev, htSHA1);
info.revCount = gitInfo.revCount;
return info;
}
else abort();
}
// This will return the flake which corresponds to a given FlakeRef. The lookupFlake is done within this function.
Flake getFlake(EvalState & state, const FlakeRef & flakeRef, bool impureIsAllowed = false)
{
FlakeSourceInfo sourceInfo = fetchFlake(state, flakeRef);
debug("got flake source '%s' with revision %s",
sourceInfo.storePath, sourceInfo.rev.value_or(Hash(htSHA1)).to_string(Base16, false));
auto flakePath = sourceInfo.storePath;
state.store->assertStorePath(flakePath);
if (state.allowedPaths)
state.allowedPaths->insert(flakePath);
Flake flake(flakeRef);
if (std::get_if<FlakeRef::IsGitHub>(&flakeRef.data)) {
if (sourceInfo.rev)
flake.ref = FlakeRef(flakeRef.baseRef().to_string()
+ "/" + sourceInfo.rev->to_string(Base16, false));
}
flake.path = flakePath;
flake.revCount = sourceInfo.revCount;
Value vInfo;
state.evalFile(flakePath + "/flake.nix", vInfo); // FIXME: symlink attack
state.forceAttrs(vInfo);
if (auto name = vInfo.attrs->get(state.sName))
flake.id = state.forceStringNoCtx(*(**name).value, *(**name).pos);
else
throw Error("flake lacks attribute 'name'");
if (auto description = vInfo.attrs->get(state.sDescription))
flake.description = state.forceStringNoCtx(*(**description).value, *(**description).pos);
if (auto requires = vInfo.attrs->get(state.symbols.create("requires"))) {
state.forceList(*(**requires).value, *(**requires).pos);
for (unsigned int n = 0; n < (**requires).value->listSize(); ++n)
flake.requires.push_back(FlakeRef(state.forceStringNoCtx(
*(**requires).value->listElems()[n], *(**requires).pos)));
}
if (std::optional<Attr *> nonFlakeRequires = vInfo.attrs->get(state.symbols.create("nonFlakeRequires"))) {
state.forceAttrs(*(**nonFlakeRequires).value, *(**nonFlakeRequires).pos);
for (Attr attr : *(*(**nonFlakeRequires).value).attrs) {
std::string myNonFlakeUri = state.forceStringNoCtx(*attr.value, *attr.pos);
FlakeRef nonFlakeRef = FlakeRef(myNonFlakeUri);
flake.nonFlakeRequires.insert_or_assign(attr.name, nonFlakeRef);
}
}
if (auto provides = vInfo.attrs->get(state.symbols.create("provides"))) {
state.forceFunction(*(**provides).value, *(**provides).pos);
flake.vProvides = (**provides).value;
} else
throw Error("flake lacks attribute 'provides'");
const Path lockFile = flakePath + "/flake.lock"; // FIXME: symlink attack
flake.lockFile = readLockFile(lockFile);
return flake;
}
// Get the `NonFlake` corresponding to a `FlakeRef`.
NonFlake getNonFlake(EvalState & state, const FlakeRef & flakeRef, FlakeId flakeId)
{
FlakeSourceInfo sourceInfo = fetchFlake(state, flakeRef);
debug("got non-flake source '%s' with revision %s",
sourceInfo.storePath, sourceInfo.rev.value_or(Hash(htSHA1)).to_string(Base16, false));
auto flakePath = sourceInfo.storePath;
state.store->assertStorePath(flakePath);
if (state.allowedPaths)
state.allowedPaths->insert(flakePath);
NonFlake nonFlake(flakeRef);
if (std::get_if<FlakeRef::IsGitHub>(&flakeRef.data)) {
if (sourceInfo.rev)
nonFlake.ref = FlakeRef(flakeRef.baseRef().to_string()
+ "/" + sourceInfo.rev->to_string(Base16, false));
}
nonFlake.path = flakePath;
nonFlake.id = flakeId;
return nonFlake;
}
/* Given a flake reference, recursively fetch it and its
dependencies.
FIXME: this should return a graph of flakes.
*/
Dependencies resolveFlake(EvalState & state, const FlakeRef & topRef, bool impureTopRef, bool isTopFlake = true)
{
Flake flake = getFlake(state, topRef, isTopFlake && impureTopRef);
Dependencies deps(flake);
for (auto & nonFlakeInfo : flake.nonFlakeRequires)
deps.nonFlakeDeps.push_back(getNonFlake(state, nonFlakeInfo.second, nonFlakeInfo.first));
for (auto & newFlakeRef : flake.requires)
deps.flakeDeps.push_back(resolveFlake(state, newFlakeRef, impureTopRef, false));
return deps;
}
LockFile::FlakeEntry dependenciesToFlakeEntry(Dependencies & deps)
{
LockFile::FlakeEntry entry(deps.flake.ref);
for (Dependencies & deps : deps.flakeDeps)
entry.flakeEntries.insert_or_assign(deps.flake.id, dependenciesToFlakeEntry(deps));
for (NonFlake & nonFlake : deps.nonFlakeDeps)
entry.nonFlakeEntries.insert_or_assign(nonFlake.id, nonFlake.ref);
return entry;
}
LockFile getLockFile(EvalState & evalState, FlakeRef & flakeRef, bool impureTopRef)
{
Dependencies deps = resolveFlake(evalState, flakeRef, impureTopRef);
LockFile::FlakeEntry entry = dependenciesToFlakeEntry(deps);
LockFile lockFile;
lockFile.flakeEntries = entry.flakeEntries;
lockFile.nonFlakeEntries = entry.nonFlakeEntries;
return lockFile;
}
void updateLockFile(EvalState & state, Path path, bool impureTopRef)
{
// 'path' is the path to the local flake repo.
FlakeRef flakeRef = FlakeRef("file://" + path);
if (std::get_if<FlakeRef::IsGit>(&flakeRef.data)) {
LockFile lockFile = getLockFile(state, flakeRef, impureTopRef);
writeLockFile(lockFile, path + "/flake.lock");
} else if (std::get_if<FlakeRef::IsGitHub>(&flakeRef.data)) {
throw UsageError("you can only update local flakes, not flakes on GitHub");
} else {
throw UsageError("you can only update local flakes, not flakes through their FlakeId");
}
}
// Return the `provides` of the top flake, while assigning to `v` the provides
// of the dependencies as well.
Value * makeFlakeValue(EvalState & state, FlakeUri flakeUri, Value & v)
{
FlakeRef flakeRef = FlakeRef(flakeUri);
Dependencies deps = resolveFlake(state, flakeRef, impure);
// // FIXME: we should call each flake with only its dependencies
// // (rather than the closure of the top-level flake).
auto vResult = state.allocValue();
// This will store the attribute set of the `nonFlakeRequires` and the `requires.provides`.
state.mkAttrs(*vResult, deps.flakeDeps.size());
Value * vTop = 0;
for (auto & flake : deps.flakeDeps) {
auto vFlake = state.allocAttr(*vResult, flake.id);
if (deps.topFlakeId == flake.id) vTop = vFlake;
state.mkAttrs(*vFlake, 4);
mkString(*state.allocAttr(*vFlake, state.sDescription), flake.description);
state.store->assertStorePath(flake.path);
mkString(*state.allocAttr(*vFlake, state.sOutPath), flake.path, {flake.path});
if (flake.second.revCount)
mkInt(*state.allocAttr(*vFlake, state.symbols.create("revCount")), *flake.revCount);
auto vProvides = state.allocAttr(*vFlake, state.symbols.create("provides"));
mkApp(*vProvides, *flake.vProvides, *vResult); // Should this be vResult or vFlake??? Or both!
vFlake->attrs->sort();
}
vResult->attrs->sort();
v = *vResult;
assert(vTop);
return vTop;
}
// This function is exposed to be used in nix files.
static void prim_getFlake(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
makeFlakeValue(state, state.forceStringNoCtx(*args[0], pos), false, v);
}
static RegisterPrimOp r2("getFlake", 1, prim_getFlake);
}