Github user pbchou commented on a diff in the pull request:
https://github.com/apache/trafficserver/pull/834#discussion_r78413984
--- Diff: proxy/ParentConsistentHash.cc ---
@@ -63,21 +66,104 @@ ParentConsistentHash::getPathHash(HttpRequestData
*hrdata, ATSHash64 *h)
{
const char *tmp = NULL;
int len;
- URL *url = hrdata->hdr->url_get();
+ URL *url = hrdata->hdr->url_get();
+ int num_dirs = 0;
+
+ // Use over-ride URL from HttpTransact::State's
cache_info.parent_selection_url, if present.
+ URL *ps_url = NULL;
+ Debug("parent_select", "hrdata->cache_info_parent_selection_url = %p",
hrdata->cache_info_parent_selection_url);
+ if (hrdata->cache_info_parent_selection_url) {
+ ps_url = *(hrdata->cache_info_parent_selection_url);
+ Debug("parent_select", "ps_url = %p", ps_url);
+ if (ps_url) {
+ tmp = ps_url->string_get_ref(&len);
+ if (tmp && len > 0) {
+ // Print the over-ride URL
+ Debug("parent_select", "Using Over-Ride String='%.*s'.", len, tmp);
+ h->update(tmp, len);
+ h->final();
+ return h->get();
+ }
+ }
+ }
// Always hash on '/' because paths returned by ATS are always stripped
of it
h->update("/", 1);
tmp = url->path_get(&len);
- if (tmp) {
+
+ if (tmp && len > 0) {
+ // Print the Original path.
+ Debug("parent_select", "Original Path='%.*s'.", len, tmp);
+
+ // Process the 'maxdirs' directive.
+ if (max_dirs != 0) {
+ // Determine number of directory components in the path.
+ // NOTE: Leading '/' is gone already.
+ for (int x = 0; x < len; x++) {
+ if (tmp[x] == '/')
+ num_dirs++;
+ }
+ // If max_dirs positive , include directory components from the left
up to max_dirs.
+ // If max_dirs negative , include directory components from the left
up to num_dirs - ( abs(max_dirs) - 1 ).
+ int limit = 0;
+ if (max_dirs > 0)
+ limit = max_dirs;
+ else if (max_dirs < 0) {
+ int md = abs(max_dirs) - 1;
+ if (md < num_dirs)
+ limit = num_dirs - md;
+ else
+ limit = 0;
+ }
+ if (limit > 0) {
+ int x = 0;
+ int count = 0;
+ for (; x < len; x++) {
+ if (tmp[x] == '/')
+ count++;
+ if (count == limit) {
+ len = x + 1;
+ break;
+ }
+ }
+ } else {
+ len = 0;
+ }
+ }
+
+ // Print the post 'maxdirs' path.
+ Debug("parent_select", "Post-maxdirs Path='%.*s'.", len, tmp);
+
+ // Process the 'fname' directive.
+ // The file name (if any) is filtered out if set to ignore the file
name or max_dirs was non-zero.
+ // The file name (if any) consists of the characters at the end of the
path beyond the final '/'.
+ // The length of the path string (to be passed to the hash generator)
is shortened to accomplish the filtering.
+ if (ignore_fname || max_dirs != 0) {
--- End diff --
Well, the negative maxdirs used to mean INCLUDE from the end of the path
rather than EXCLUDE from the end of the path. We changed the semantic
internally before submitting to the community. I think that from the user
perspective it is not a bad thing to be able to say "fname=ignore" when you
don't want the file name instead of doing something like "max_dirs=-1". Yes, it
achieves the same result, but this is a user-facing configuration file option.
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