diff options
| -rw-r--r-- | doc/manual/command-ref/conf-file.xml | 27 | ||||
| -rw-r--r-- | src/libstore/builtins/fetchurl.cc | 14 | ||||
| -rw-r--r-- | src/libstore/globals.hh | 3 |
3 files changed, 44 insertions, 0 deletions
diff --git a/doc/manual/command-ref/conf-file.xml b/doc/manual/command-ref/conf-file.xml index 9c55526a3..d0f1b09ca 100644 --- a/doc/manual/command-ref/conf-file.xml +++ b/doc/manual/command-ref/conf-file.xml @@ -370,6 +370,33 @@ false</literal>.</para> </varlistentry> + <varlistentry xml:id="conf-hashed-mirrors"><term><literal>hashed-mirrors</literal></term> + + <listitem><para>A list of web servers used by + <function>builtins.fetchurl</function> to obtain files by hash. + Given a hash type <replaceable>ht</replaceable> and a base-16 hash + <replaceable>h</replaceable>, Nix will try to download the file + from + <literal>hashed-mirror/<replaceable>ht</replaceable>/<replaceable>h</replaceable></literal>. + This allows files to be downloaded even if they have disappeared + from their original URI. For example, given the hashed mirror + <literal>http://tarballs.example.com/</literal>, when building the + derivation + +<programlisting> +builtins.fetchurl { + url = "https://example.org/foo-1.2.3.tar.xz"; + sha256 = "2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae"; +} +</programlisting> + + Nix will attempt to download this file from + <literal>http://tarballs.example.com/sha256/2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae</literal> + first. If it is not available there, if will try the original URI.</para></listitem> + + </varlistentry> + + <varlistentry xml:id="conf-http-connections"><term><literal>http-connections</literal></term> <listitem><para>The maximum number of parallel TCP connections diff --git a/src/libstore/builtins/fetchurl.cc b/src/libstore/builtins/fetchurl.cc index 6585a480d..4fb5d8a06 100644 --- a/src/libstore/builtins/fetchurl.cc +++ b/src/libstore/builtins/fetchurl.cc @@ -58,6 +58,20 @@ void builtinFetchurl(const BasicDerivation & drv, const std::string & netrcData) } }; + /* Try the hashed mirrors first. */ + if (getAttr("outputHashMode") == "flat") + for (auto hashedMirror : settings.hashedMirrors.get()) + try { + if (!hasSuffix(hashedMirror, "/")) hashedMirror += '/'; + std::optional<HashType> ht = parseHashTypeOpt(getAttr("outputHashAlgo")); + Hash h = newHashAllowEmpty(getAttr("outputHash"), ht); + fetch(hashedMirror + printHashType(h.type) + "/" + h.to_string(Base16, false)); + return; + } catch (Error & e) { + debug(e.what()); + } + + /* Otherwise try the specified URL. */ fetch(mainUrl); } diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh index 3406a9331..e3bb4cf84 100644 --- a/src/libstore/globals.hh +++ b/src/libstore/globals.hh @@ -335,6 +335,9 @@ public: "setuid/setgid bits or with file capabilities."}; #endif + Setting<Strings> hashedMirrors{this, {}, "hashed-mirrors", + "A list of servers used by builtins.fetchurl to fetch files by hash."}; + Setting<uint64_t> minFree{this, 0, "min-free", "Automatically run the garbage collector when free disk space drops below the specified amount."}; |