expire rust caches both incrementally and fully once a month

.github/workflows/build.yml

@@ -136,6 +136,12 @@ jobs:
       - name: install rustup components
         if: steps.cache.outputs.cache-hit != 'true'
         run: rustup component add rustfmt
+      - name: install cargo-cache
+        if: steps.cache.outputs.cache-hit != 'true'
+        run: cargo install --locked cargo-cache --version 0.8.3
+      - name: install cargo-sweep
+        if: steps.cache.outputs.cache-hit != 'true'
+        run: cargo install --locked cargo-sweep --version 0.7.0
       - name: install dependencies
         if: steps.cache.outputs.cache-hit != 'true'
         run: sudo apt-get -y install postgresql git build-essential pkg-config autoconf automake libtool bison flex libpq-dev parallel libunwind-dev sed perl

ci-build.sh

@@ -128,11 +128,11 @@ export CCACHE_COMPRESSLEVEL=9
 export CCACHE_MAXSIZE=500M
 export CCACHE_CPP2=true
 
-# purge cache if it's too old
+# periodically check to see if caches are old and purge them if so
 if [ -d "$CCACHE_DIR" ] ; then
     if [ -n "$(find $CCACHE_DIR -mtime +$CACHE_MAX_DAYS -print -quit)" ] ; then
-        echo Purging old cache $CCACHE_DIR
-        rm -rf $CCACHE_DIR
+        echo Purging old cache dirs $CCACHE_DIR $HOME/.cargo ./target
+        rm -rf $CCACHE_DIR $HOME/.cargo ./target
     fi
 fi
 
@@ -163,6 +163,9 @@ date
 time make -j$(($NPROCS + 1))
 
 ccache -s
+### incrementally purge old content from cargo source cache and target directory
+cargo cache trim --limit 100M
+cargo sweep --maxsize 500MB
 
 if [ $WITH_TESTS -eq 0 ] ; then
     echo "Build done, skipping tests"