bild: print log output if the build fails

This also switches to using `nix-build` instead of `nix build`. The reason for
this is that the latter does something with the stdout/stderr that makes it hard
to capture via tee. Idk why. Maybe I'll look into this again, or maybe not,
since nix-build works just fine.

1 files changed, 16 insertions, 2 deletions

diff --git a/bild b/bild
index 8ea07ea..fdd3dd7 100755
--- a/bild
+++ b/bild
@@ -3,9 +3,23 @@ set -ex
 prefix=$(echo $PWD | sed -e "s|^$BIZ_ROOT/*||g" -e "s|/|.|g")
 if [[ "$prefix" == "" ]]
 then
+  # TODO: make this accept any number of build targets
   target="$1"
 else
   target="$prefix.$1"
 fi
-nix build -o "$BIZ_ROOT/_bild/$target" \
-  -f $BIZ_ROOT/default.nix "$target" --show-trace
+log=$(mktemp)
+nix-build \
+    -o "$BIZ_ROOT/_bild/$target" \
+    $BIZ_ROOT/default.nix \
+    --attr "$target" \
+    --show-trace \
+    2>&1 \
+    | tee $log
+if [[ ${PIPESTATUS[0]} != 0 ]]
+then
+    o=$(gawk "match(\$0, /'(.*)'\sfailed/, a) {print a[1]}" $log \
+        | head -n 1)
+    nix log $o
+fi
+