Improve cirrus-cache.sh

Print md5 as part of cache scripts.
Address spellcheck issues (quote variables).
Remove dead variables.
Improve output in general and pipe errors to stderr.
Fully spell out curl options for better readability.
Always show error with curl.

.cirrus.yml

@@ -117,12 +117,12 @@ validate_links_task:
     LINK_CACHE_PATH: /root/link-probing-history.cache
   cache_download_script:
     - bash ci/cirrus-cache.sh download ${LINK_CACHE_NAME} ${LINK_CACHE_PATH}
-  tests_script:
     - md5sum /root/link-probing-history.cache/link_probes.history || true
+  tests_script:
     - ./ci/validate_links.sh ${LINK_CACHE_PATH}
-    - md5sum /root/link-probing-history.cache/link_probes.history
   always:
     cache_upload_script:
+      - md5sum /root/link-probing-history.cache/link_probes.history || true
       - bash ci/cirrus-cache.sh upload ${LINK_CACHE_NAME} ${LINK_CACHE_PATH}
 
 validate_file_extensions_task:

ci/cirrus-cache.sh

@@ -6,38 +6,38 @@ ACTION=${1}
 CACHE_NAME=${2}
 PATH_TO_CACHE=${3}
 
-CACHE_KEY=${CACHE_NAME}
+CACHE_URL="http://${CIRRUS_HTTP_CACHE_HOST}/${CACHE_NAME}"
-DEFAULT_CACHE_KEY=${CACHE_NAME}
 
-CACHE_URL=http://${CIRRUS_HTTP_CACHE_HOST}/${CACHE_KEY}
+TMP_PATH="/tmp/tmp-cache.tgz"
-
-TMP_PATH=/tmp/tmp-cache.tgz
 
 case "${ACTION}" in
 
 download)
-  echo "Download cache with key ${CACHE_KEY}"
+  echo "Download cache with key ${CACHE_NAME} from ${CACHE_URL}"
-
+  curl --silent --show-error --fail --location --output "${TMP_PATH}" "${CACHE_URL}" || {
-  echo "  -> try ${CACHE_URL}"
+    echo "Cache download failed" >&2
-  curl -sfSL -o ${TMP_PATH} ${CACHE_URL} || {
+    exit 0
-    echo "Cache download failed";
-    exit 0;
   }
-  du -hs ${TMP_PATH}
+  du -hs "${TMP_PATH}"
-  tar -Pxzf ${TMP_PATH}
+  tar -Pxzf "${TMP_PATH}"
-  rm ${TMP_PATH}
+  rm "${TMP_PATH}"
   ;;
 
 upload)
   echo "Upload cache to ${CACHE_URL}"
-  tar -Pczf ${TMP_PATH} ${PATH_TO_CACHE}
+  tar -Pczf "${TMP_PATH}" "${PATH_TO_CACHE}"
-  du -hs ${TMP_PATH}
+  du -hs "${TMP_PATH}"
-  curl -s -X POST --data-binary @${TMP_PATH} ${CACHE_URL}
+  curl --silent --show-error -X POST --data-binary "@${TMP_PATH}" "${CACHE_URL}" || {
+    echo "Cache upload failed" >&2
+    exit 0
+  }
   ;;
 
 *)
-  echo "Unexpected cache ACTION: ${ACTION}"
+  echo "Unexpected cache ACTION: ${ACTION}" >&2
   exit 1
   ;;
 
 esac
+
+echo "Cache ${ACTION}ed succeeded."