new: added ``cached_wget`` utility function to compose intended for charms to use.

bin/compose

@@ -2601,6 +2601,24 @@ EOF
     echo "}"
 }
 
+cached_wget() {
+    local cache_file="$CACHEDIR/$FUNCNAME.cache.$(echo "$*" | md5_compat)" \
+          url="$1"
+    if [ -e "$cache_file" ]; then
+        cat "$cache_file"
+        touch "$cache_file"
+        return 0
+    fi
+    wget -O- "${url}" |
+        tee "$cache_file"
+
+    if [ "${PIPESTATUS[0]}" != 0 ]; then
+        rm "$cache_file"
+        die "Unable to fetch '$url'."
+        return 1
+    fi
+}
+export -f cached_wget
 
 [ "$SOURCED" ] && return 0
 

test/wget

@@ -0,0 +1,109 @@
+#!/usr/bin/env bash-shlib
+# -*- mode: shell-script -*-
+
+include shunit
+
+depends sed grep git mkdir readlink
+
+export -f matches
+export grep
+
+tmp=/tmp
+tprog="../bin/compose"
+tprog=$(readlink -f $tprog)
+
+
+export PATH=".:$PATH"
+short_tprog=$(basename "$tprog")
+
+
+##
+## Convenience function
+##
+
+init_test() {
+    test_tmpdir=$(mktemp -d -t tmp.XXXXXXXXXX)
+    cd "$test_tmpdir"
+    export CACHEDIR="$test_tmpdir/.cache"
+    mkdir -p "$CACHEDIR"
+}
+
+
+
+tear_test() {
+    rm -rf "$test_tmpdir"
+}
+
+
+##
+## Tests
+##
+
+
+function test_wget {
+
+    init_test
+    PORT=45467
+    assert_list <<EOF
+
+### cached wget
+
+## -- should be able to fetch URL
+
+. "$tprog"
+
+echo -e "HTTP/1.1 200 OK\n\ntoto" | nc -l localhost $PORT &
+
+out=\$(cached_wget http://localhost:$PORT) || exit 1
+expected="toto"
+
+
+[ "\$out" == "\$expected" ] || {
+    echo -e "DIFF:\n\$(diff <(echo "\$out") <(echo "\$expected"))"
+    exit 1
+}
+
+## -- same URL should not try again to join server
+
+. "$tprog"
+
+out=\$(cached_wget http://localhost:$PORT) || exit 1
+expected="toto"
+
+[ "\$out" == "\$expected" ] || {
+    echo -e "DIFF:\n\$(diff <(echo "\$out") <(echo "\$expected"))"
+    exit 1
+}
+
+
+## -- wrong URL should complain
+
+. "$tprog"
+
+out=\$(cached_wget http://localhost:$PORT/foo) || exit 0
+echo "Was expected to fail."
+exit 1
+
+## -- and be retested
+
+. "$tprog"
+
+echo -e "HTTP/1.1 200 OK\n\ntiti" | nc -l localhost $PORT &
+
+out=\$(cached_wget http://localhost:$PORT/foo) || exit 1
+expected="titi"
+
+[ "\$out" == "\$expected" ] || {
+    echo -e "DIFF:\n\$(diff <(echo "\$out") <(echo "\$expected"))"
+    exit 1
+}
+
+
+EOF
+
+    tear_test
+}
+
+
+
+continue_on_error="0" testbench $*