Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.


// collapsed_forwarding::
// ATS plugin to allow collapsed forwarding of concurrent requests for the same
// object. This plugin is based on open_write_fail_action feature, which detects
// cache open write failure on a cache miss and returns a 502 error along with a
// special @-header indicating the reason for 502 error. The plugin acts on the
// error by using an internal redirect follow back to itself, essentially blocking
// the request until a response arrives, at which point, relies on read-while-writer
// feature to start downloading the object to all waiting clients. The following
// config parameters are assumed to be set for this plugin to work:
// proxy.config.http.cache.open_write_fail_action        1 /////////////////////////
// proxy.config.cache.enable_read_while_writer           1 /////////////////////////
// proxy.config.http.number_of_redirections             10 /////////////////////////
// proxy.config.http.redirect_use_orig_cache_key         1 /////////////////////////
// proxy.config.http.background_fill_active_timeout      0 /////////////////////////
// proxy.config.http.background_fill_completed_threshold 0 /////////////////////////
// Additionally, given that collapsed forwarding works based on cache write
// lock failure detection, the plugin requires cache to be enabled and ready.
// On a restart, Traffic Server typically takes a few seconds to initialize
// the cache depending on the cache size and number of dirents. While the
// cache is not ready yet, collapsed forwarding can not detect the write lock
// contention and so can not work. The setting proxy.config.http.wait_for_cache
// may be enabled which allows blocking incoming connections from being
// accepted until cache is ready.
// This plugin currently supports only per-remap mode activation.

More details are available at



    sudo make install

If you don't have the traffic server binaries in your path, then you will need
to specify the path to tsxs manually:

    make TSXS=/opt/trafficserver/bin/tsxs
    sudo make TSXS=/opt/trafficserver/bin/tsxs install


    Add @plugin=collapsed_forwarding.so to your remap.config rules. The plugin optionally
accepts a --delay=<delay> parameter and a --retries=<retries> parameter that can help tune
the total number of retries and the delay between consecutive retries.