Store: Add a method for getting build logs

This allows various Store implementations to provide different ways to
get build logs. For example, BinaryCacheStore can get the build logs
from the binary cache.

Also, remove the log-servers option since we can use substituters for
this.

1 files changed, 35 insertions, 0 deletions

diff --git a/src/libstore/local-fs-store.cc b/src/libstore/local-fs-store.cc
index 4571a2211cd2..c5da73dba36c 100644
--- a/src/libstore/local-fs-store.cc
+++ b/src/libstore/local-fs-store.cc
@@ -2,6 +2,8 @@
 #include "fs-accessor.hh"
 #include "store-api.hh"
 #include "globals.hh"
+#include "compression.hh"
+#include "derivations.hh"
 
 namespace nix {
 
@@ -84,4 +86,37 @@ void LocalFSStore::narFromPath(const Path & path, Sink & sink)
     dumpPath(getRealStoreDir() + std::string(path, storeDir.size()), sink);
 }
 
+const string LocalFSStore::drvsLogDir = "drvs";
+
+std::shared_ptr<std::string> LocalFSStore::getBuildLog(const Path & path_)
+{
+    auto path(path_);
+
+    assertStorePath(path);
+
+    if (!isDerivation(path)) {
+        path = queryPathInfo(path)->deriver;
+        if (path == "") return nullptr;
+    }
+
+    string baseName = baseNameOf(path);
+
+    for (int j = 0; j < 2; j++) {
+
+        Path logPath =
+            j == 0
+            ? (format("%1%/%2%/%3%/%4%") % logDir % drvsLogDir % string(baseName, 0, 2) % string(baseName, 2)).str()
+            : (format("%1%/%2%/%3%") % logDir % drvsLogDir % baseName).str();
+        Path logBz2Path = logPath + ".bz2";
+
+        if (pathExists(logPath))
+            return std::make_shared<std::string>(readFile(logPath));
+
+        else if (pathExists(logBz2Path))
+            return decompress("bzip2", readFile(logBz2Path));
+    }
+
+    return nullptr;
+}
+
 }