Provide network download fallback

in case the base infrastructure for providing the networks

https://tests.stockfishchess.org/nns

is down, use an alternate github repo for downloading networks during the build.

No functional change

diff --git a/src/Makefile b/src/Makefile
index 602beef..8572369 100644 (file)
--- a/src/Makefile
+++ b/src/Makefile
@@ -821,25 +821,35 @@ clean: objclean profileclean
 net:
        $(eval nnuenet := $(shell grep EvalFileDefaultName evaluate.h | grep define | sed 's/.*\(nn-[a-z0-9]\{12\}.nnue\).*/\1/'))
        @echo "Default net: $(nnuenet)"
-       $(eval nnuedownloadurl := https://tests.stockfishchess.org/api/nn/$(nnuenet))
+       $(eval nnuedownloadurl1 := https://tests.stockfishchess.org/api/nn/$(nnuenet))
+       $(eval nnuedownloadurl2 := https://github.com/official-stockfish/networks/raw/master/$(nnuenet))
        $(eval curl_or_wget := $(shell if hash curl 2>/dev/null; then echo "curl -skL"; elif hash wget 2>/dev/null; then echo "wget -qO-"; fi))
-       @if test -f "$(nnuenet)"; then \
-            echo "Already available."; \
-         else \
-            if [ "x$(curl_or_wget)" = "x" ]; then \
-               echo "Automatic download failed: neither curl nor wget is installed. Install one of these tools or download the net manually"; exit 1; \
-            else \
-               echo "Downloading $(nnuedownloadurl)"; $(curl_or_wget) $(nnuedownloadurl) > $(nnuenet);\
-            fi; \
-        fi;
+       @if [ "x$(curl_or_wget)" = "x" ]; then \
+           echo "Automatic download failed: neither curl nor wget is installed. Install one of these tools or download the net manually"; exit 1; \
+        fi
        $(eval shasum_command := $(shell if hash shasum 2>/dev/null; then echo "shasum -a 256 "; elif hash sha256sum 2>/dev/null; then echo "sha256sum "; fi))
-       @if [ "x$(shasum_command)" != "x" ]; then \
-           if [ "$(nnuenet)" != "nn-"`$(shasum_command) $(nnuenet) | cut -c1-12`".nnue" ]; then \
-                echo "Failed download or $(nnuenet) corrupted, please delete!"; exit 1; \
-            fi \
-         else \
+       @if [ "x$(shasum_command)" = "x" ]; then \
             echo "shasum / sha256sum not found, skipping net validation"; \
         fi
+       @for nnuedownloadurl in "$(nnuedownloadurl1)" "$(nnuedownloadurl2)"; do \
+          if test -f "$(nnuenet)"; then \
+             echo "$(nnuenet) available."; \
+          else \
+             if [ "x$(curl_or_wget)" != "x" ]; then \
+                echo "Downloading $${nnuedownloadurl}"; $(curl_or_wget) $${nnuedownloadurl} > $(nnuenet);\
+             fi; \
+          fi; \
+          if [ "x$(shasum_command)" != "x" ]; then \
+             if [ "$(nnuenet)" != "nn-"`$(shasum_command) $(nnuenet) | cut -c1-12`".nnue" ]; then \
+                echo "Removing failed download"; rm -f $(nnuenet); \
+             else \
+                echo "Network validated"; break; \
+             fi; \
+          fi; \
+       done
+       @if ! test -f "$(nnuenet)"; then \
+           echo "Failed to download $(nnuenet)."; \
+       fi
 
 # clean binaries and objects
 objclean: