1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
|
#include "primops.hh"
#include "store-api.hh"
#include "make-content-addressed.hh"
#include "url.hh"
namespace nix {
static void prim_fetchClosure(EvalState & state, const PosIdx pos, Value * * args, Value & v)
{
state.forceAttrs(*args[0], pos, "while evaluating the argument passed to builtins.fetchClosure");
std::optional<std::string> fromStoreUrl;
std::optional<StorePath> fromPath;
bool toCA = false;
std::optional<StorePath> toPath;
for (auto & attr : *args[0]->attrs) {
const auto & attrName = state.symbols[attr.name];
if (attrName == "fromPath") {
NixStringContext context;
fromPath = state.coerceToStorePath(attr.pos, *attr.value, context,
"while evaluating the 'fromPath' attribute passed to builtins.fetchClosure");
}
else if (attrName == "toPath") {
state.forceValue(*attr.value, attr.pos);
toCA = true;
if (attr.value->type() != nString || attr.value->string.s != std::string("")) {
NixStringContext context;
toPath = state.coerceToStorePath(attr.pos, *attr.value, context,
"while evaluating the 'toPath' attribute passed to builtins.fetchClosure");
}
}
else if (attrName == "fromStore")
fromStoreUrl = state.forceStringNoCtx(*attr.value, attr.pos,
"while evaluating the 'fromStore' attribute passed to builtins.fetchClosure");
else
throw Error({
.msg = hintfmt("attribute '%s' isn't supported in call to 'fetchClosure'", attrName),
.errPos = state.positions[pos]
});
}
if (!fromPath)
throw Error({
.msg = hintfmt("attribute '%s' is missing in call to 'fetchClosure'", "fromPath"),
.errPos = state.positions[pos]
});
if (!fromStoreUrl)
throw Error({
.msg = hintfmt("attribute '%s' is missing in call to 'fetchClosure'", "fromStore"),
.errPos = state.positions[pos]
});
auto parsedURL = parseURL(*fromStoreUrl);
if (parsedURL.scheme != "http" &&
parsedURL.scheme != "https" &&
!(getEnv("_NIX_IN_TEST").has_value() && parsedURL.scheme == "file"))
throw Error({
.msg = hintfmt("'fetchClosure' only supports http:// and https:// stores"),
.errPos = state.positions[pos]
});
if (!parsedURL.query.empty())
throw Error({
.msg = hintfmt("'fetchClosure' does not support URL query parameters (in '%s')", *fromStoreUrl),
.errPos = state.positions[pos]
});
auto fromStore = openStore(parsedURL.to_string());
if (toCA) {
if (!toPath || !state.store->isValidPath(*toPath)) {
auto remappings = makeContentAddressed(*fromStore, *state.store, { *fromPath });
auto i = remappings.find(*fromPath);
assert(i != remappings.end());
if (toPath && *toPath != i->second)
throw Error({
.msg = hintfmt("rewriting '%s' to content-addressed form yielded '%s', while '%s' was expected",
state.store->printStorePath(*fromPath),
state.store->printStorePath(i->second),
state.store->printStorePath(*toPath)),
.errPos = state.positions[pos]
});
if (!toPath)
throw Error({
.msg = hintfmt(
"rewriting '%s' to content-addressed form yielded '%s'; "
"please set this in the 'toPath' attribute passed to 'fetchClosure'",
state.store->printStorePath(*fromPath),
state.store->printStorePath(i->second)),
.errPos = state.positions[pos]
});
}
} else {
if (!state.store->isValidPath(*fromPath))
copyClosure(*fromStore, *state.store, RealisedPath::Set { *fromPath });
toPath = fromPath;
}
/* In pure mode, require a CA path. */
if (evalSettings.pureEval) {
auto info = state.store->queryPathInfo(*toPath);
if (!info->isContentAddressed(*state.store))
throw Error({
.msg = hintfmt("in pure mode, 'fetchClosure' requires a content-addressed path, which '%s' isn't",
state.store->printStorePath(*toPath)),
.errPos = state.positions[pos]
});
}
state.mkStorePathString(*toPath, v);
}
static RegisterPrimOp primop_fetchClosure({
.name = "__fetchClosure",
.args = {"args"},
.doc = R"(
Fetch a Nix store closure from a binary cache, rewriting it into
content-addressed form. For example,
```nix
builtins.fetchClosure {
fromStore = "https://cache.nixos.org";
fromPath = /nix/store/r2jd6ygnmirm2g803mksqqjm4y39yi6i-git-2.33.1;
toPath = /nix/store/ldbhlwhh39wha58rm61bkiiwm6j7211j-git-2.33.1;
}
```
fetches `/nix/store/r2jd...` from the specified binary cache,
and rewrites it into the content-addressed store path
`/nix/store/ldbh...`.
If `fromPath` is already content-addressed, or if you are
allowing impure evaluation (`--impure`), then `toPath` may be
omitted.
To find out the correct value for `toPath` given a `fromPath`,
you can use `nix store make-content-addressed`:
```console
# nix store make-content-addressed --from https://cache.nixos.org /nix/store/r2jd6ygnmirm2g803mksqqjm4y39yi6i-git-2.33.1
rewrote '/nix/store/r2jd6ygnmirm2g803mksqqjm4y39yi6i-git-2.33.1' to '/nix/store/ldbhlwhh39wha58rm61bkiiwm6j7211j-git-2.33.1'
```
This function is similar to `builtins.storePath` in that it
allows you to use a previously built store path in a Nix
expression. However, it is more reproducible because it requires
specifying a binary cache from which the path can be fetched.
Also, requiring a content-addressed final store path avoids the
need for users to configure binary cache public keys.
This function is only available if you enable the experimental
feature `fetch-closure`.
)",
.fun = prim_fetchClosure,
.experimentalFeature = Xp::FetchClosure,
});
}
|
