Using backup server when original download server fails

Until now, the main download script could only check one server for the
given URL. However, ultimately the actual server that a file is downloaded
from is irrelevant for this project: we actually check its
checksum. Especially in the case of software (which are distributed over
many servers), this can usually be very annoying: the servers may not
properly communicate with the running system and even the 10 trials won't
be enough.

With this commit, the download script
`reproduce/analysis/bash/download-multi-try' can take a new optional
argument (a 5th argument). It assumes this argument is a space-separated
list of server(s) to use as backup for the original URL. When downloading
from the original URL fails, it will look into this list and try
downloading the same file from each given server.

4 files changed, 40 insertions, 7 deletions

diff --git a/reproduce/analysis/bash/download-multi-try b/reproduce/analysis/bash/download-multi-try
index dec2539..7a5f8f2 100755
--- a/reproduce/analysis/bash/download-multi-try
+++ b/reproduce/analysis/bash/download-multi-try
@@ -51,11 +51,13 @@ set -e
 
 
 
-# Input arguments and necessary sanity checks.
+# Input arguments and necessary sanity checks. Note that the 5th argument
+# (backup servers) isn't mandatory.
 inurl="$3"
 outname="$4"
 lockfile="$2"
 downloader="$1"
+backupservers="$5"
 if [ "x$downloader" = x ]; then
     echo "$0: downloader (first argument) not given."; exit 1;
 fi
@@ -73,6 +75,13 @@ fi
 
 
 
+# Separate the actual filename, to possibly use backup server.
+urlfile=$(echo "$inurl" | awk -F "/" '{print $NF}')
+
+
+
+
+
 # Try downloading multiple times before crashing.
 counter=0
 maxcounter=10
@@ -107,8 +116,19 @@ while [ ! -f "$outname" ]; do
     if [ x"$lockfile" = xnolock ]; then
         if ! $downloader $outname $inurl; then rm -f $outname; fi
     else
+        # Try downloading from the requested URL.
         flock "$lockfile" bash -c \
               "if ! $downloader $outname $inurl; then rm -f $outname; fi"
+
+        # If it failed, try the backup server(s).
+        if [ ! -f "$outname" ]; then
+            if [ x"$backupservers" != x ]; then
+                for bs in "$backupservers"; do
+                    flock "$lockfile" bash -c \
+                          "if ! $downloader $outname $bs/$urlfile; then rm -f $outname; fi"
+                done
+            fi
+        fi
     fi
 
 done
diff --git a/reproduce/software/make/basic.mk b/reproduce/software/make/basic.mk
index d08ba62..2cad9f9 100644
--- a/reproduce/software/make/basic.mk
+++ b/reproduce/software/make/basic.mk
@@ -82,6 +82,10 @@ export BASH_ENV := $(shell pwd)/reproduce/software/shell/bashrc.sh
 top-level-programs = low-level-links gcc
 all: $(foreach p, $(top-level-programs), $(ibidir)/$(p))
 
+# Servers to use as backup, later this should go in a file that is not
+# under version control (the actual server that the tarbal comes from is
+# irrelevant).
+backupservers = http://akhlaghi.org/reproduce-software
 
 
 
@@ -236,15 +240,19 @@ $(tarballs): $(tdir)/%: | $(lockdir)
 	      \
 	  touch $(lockdir)/download; \
 	  $(downloadwrapper) "$$downloader" $(lockdir)/download \
-	                     $$tarballurl "$@.unchecked"; \
+	                     $$tarballurl "$@.unchecked" "$(backupservers)"; \
 	fi; \
 	                                                \
 	                                                \
 	if type sha512sum > /dev/null 2>/dev/null; then \
 	  checksum=$$(sha512sum "$@.unchecked" | awk '{print $$1}'); \
-	  echo "$*: should be '$$c', is '$$checksum'"; \
-	  if [ x$$checksum = x$$c ]; then mv "$@.unchecked" "$@"; \
-	  else echo "ERROR: Non-matching checksum for '$*'."; exit 1; \
+	  if [ x"$$checksum" = x"$$c" ]; then \
+	    mv "$@.unchecked" "$@"; \
+	  else \
+	    echo "ERROR: Non-matching checksum for '$*'."; \
+	    echo "Checksum should be: $$c"; \
+	    echo "Checksum is:        $$checksum"; \
+	    exit 1; \
 	  fi; \
 	else mv "$@.unchecked" "$@"; \
 	fi;
diff --git a/reproduce/software/make/high-level.mk b/reproduce/software/make/high-level.mk
index 53bef55..8457690 100644
--- a/reproduce/software/make/high-level.mk
+++ b/reproduce/software/make/high-level.mk
@@ -100,6 +100,11 @@ export LIBRARY_PATH := $(sys_library_path)
 export PROJECT_STATUS := configure_highlevel
 export BASH_ENV := $(shell pwd)/reproduce/software/shell/bashrc.sh
 
+# Servers to use as backup, later this should go in a file that is not
+# under version control (the actual server that the tarbal comes from is
+# irrelevant).
+backupservers = http://akhlaghi.org/reproduce-software
+
 # Building flags:
 #
 # C++ flags: when we build GCC, the C++ standard library needs to link with
@@ -321,7 +326,7 @@ $(tarballs): $(tdir)/%: | $(lockdir)
 	  touch $(lockdir)/download
 	  downloader="wget --no-use-server-timestamps -O"
 	  $(downloadwrapper) "$$downloader" $(lockdir)/download \
-	                     $$tarballurl "$@.unchecked"
+	                     $$tarballurl "$@.unchecked" "$(backupservers)"
 	fi
 
         # Make sure this is the expected tarball. Note that we now have a
diff --git a/reproduce/software/make/python.mk b/reproduce/software/make/python.mk
index 8c7b6f0..2e74c16 100644
--- a/reproduce/software/make/python.mk
+++ b/reproduce/software/make/python.mk
@@ -259,7 +259,7 @@ $(pytarballs): $(tdir)/%:
 	  touch $(lockdir)/download
 	  downloader="wget --no-use-server-timestamps -O"
 	  $(downloadwrapper) "$$downloader" $(lockdir)/download \
-	                     $$tarballurl "$@.unchecked"
+	                     $$tarballurl "$@.unchecked" "$(backupservers)"
 	fi
 
         # Make sure this is the expected tarball. Note that we now have a