nix-store -l: Fetch build logs from the Internet

If a build log is not available locally, then ‘nix-store -l’ will now
try to download it from the servers listed in the ‘log-servers’ option
in nix.conf. For instance, if you have:

  log-servers = http://hydra.nixos.org/log

then it will try to get logs from http://hydra.nixos.org/log/<base
name of the store path>. So you can do things like:

  $ nix-store -l $(which xterm)

and get a log even if xterm wasn't built locally.
This commit is contained in:
Eelco Dolstra 2014-05-21 17:19:36 +02:00
parent eac5841970
commit 9f9080e2c0
9 changed files with 144 additions and 93 deletions

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@ -10,6 +10,7 @@ PACKAGE_VERSION = @PACKAGE_VERSION@
bash = @bash@
bindir = @bindir@
bsddiff_compat_include = @bsddiff_compat_include@
curl = @curl@
datadir = @datadir@
datarootdir = @datarootdir@
dblatex = @dblatex@

View file

@ -465,6 +465,20 @@ flag, e.g. <literal>--option gc-keep-outputs false</literal>.</para>
</varlistentry>
<varlistentry xml:id="conf-log-servers"><term><literal>log-servers</literal></term>
<listitem>
<para>A list of URL prefixes (such as
<literal>http://hydra.nixos.org/log</literal>) from which
<command>nix-store -l</command> will try to fetch build logs if
theyre not available locally.</para>
</listitem>
</varlistentry>
</variablelist>
</para>

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@ -1147,9 +1147,14 @@ the store path is used.</para>
<para>Build logs are kept in
<filename>/nix/var/log/nix/drvs</filename>. However, there is no
guarantee that a build log is available for any particular store
path. For instance, if the path was downloaded as a pre-built binary
through a substitute, then the log is unavailable.</para>
guarantee that a build log is available for any particular store path.
For instance, if the path was downloaded as a pre-built binary through
a substitute, then the log is unavailable. If the log is not available
locally, then <command>nix-store</command> will try to download the
log from the servers specified in the Nix option
<option>log-servers</option>. For example, if its set to
<literal>http://hydra.nixos.org/log</literal>, then Nix will check
<literal>http://hydra.nixos.org/log/<replaceable>base-name</replaceable></literal>.</para>
</refsection>

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@ -147,6 +147,7 @@ void Settings::update()
get(envKeepDerivations, "env-keep-derivations");
get(sshSubstituterHosts, "ssh-substituter-hosts");
get(useSshSubstituter, "use-ssh-substituter");
get(logServers, "log-servers");
string subs = getEnv("NIX_SUBSTITUTERS", "default");
if (subs == "default") {

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@ -197,6 +197,9 @@ struct Settings {
/* Whether to show a stack trace if Nix evaluation fails. */
bool showTrace;
/* A list of URL prefixes that can return Nix build logs. */
Strings logServers;
private:
SettingsMap settings, overrides;

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@ -901,7 +901,7 @@ string runProgram(Path program, bool searchPath, const Strings & args)
/* Wait for the child to finish. */
int status = pid.wait(true);
if (!statusOk(status))
throw Error(format("program `%1%' %2%")
throw ExecError(format("program `%1%' %2%")
% program % statusToString(status));
return result;

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@ -257,6 +257,8 @@ void killUser(uid_t uid);
string runProgram(Path program, bool searchPath = false,
const Strings & args = Strings());
MakeError(ExecError, Error)
/* Close all file descriptors except stdin, stdout, stderr, and those
listed in the given set. Good practice in child processes. */
void closeMostFDs(const set<int> & exceptions);

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@ -7,3 +7,5 @@ nix-store_SOURCES := $(wildcard $(d)/*.cc)
nix-store_LIBS = libmain libstore libutil libformat
nix-store_LDFLAGS = -lbz2
nix-store_CXXFLAGS = -DCURL=\"$(curl)\"

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@ -467,10 +467,11 @@ static void opReadLog(Strings opFlags, Strings opArgs)
foreach (Strings::iterator, i, opArgs) {
Path path = useDeriver(followLinksToStorePath(*i));
for (int j = 0; j <= 2; j++) {
if (j == 2) throw Error(format("build log of derivation `%1%' is not available") % path);
string baseName = baseNameOf(path);
bool found = false;
for (int j = 0; j < 2; j++) {
string baseName = baseNameOf(path);
Path logPath =
j == 0
? (format("%1%/%2%/%3%/%4%") % settings.nixLogDir % drvsLogDir % string(baseName, 0, 2) % string(baseName, 2)).str()
@ -481,6 +482,7 @@ static void opReadLog(Strings opFlags, Strings opArgs)
/* !!! Make this run in O(1) memory. */
string log = readFile(logPath);
writeFull(STDOUT_FILENO, (const unsigned char *) log.data(), log.size());
found = true;
break;
}
@ -500,9 +502,30 @@ static void opReadLog(Strings opFlags, Strings opArgs)
writeFull(STDOUT_FILENO, buf, n);
} while (err != BZ_STREAM_END);
BZ2_bzReadClose(&err, bz);
found = true;
break;
}
}
if (!found) {
for (auto & i : settings.logServers) {
string prefix = i;
if (!prefix.empty() && prefix.back() != '/') prefix += '/';
string url = prefix + baseName;
try {
string log = runProgram(CURL, true, {"--fail", "--location", "--silent", "--", url});
std::cout << "(using build log from " << url << ")" << std::endl;
std::cout << log;
found = true;
break;
} catch (ExecError & e) {
/* Ignore errors from curl. FIXME: actually, might be
nice to print a warning on HTTP status != 404. */
}
}
}
if (!found) throw Error(format("build log of derivation `%1%' is not available") % path);
}
}