go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/gae/filter/readonly/filter.go (about)

     1  // Copyright 2017 The LUCI Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // Package readonly implements a filter that enforces read-only accesses to
    16  // services.
    17  //
    18  // This can be useful in hybrid environments where one cluster wants to read
    19  // from a cache-backed datastore, but cannot modify the cache, so reads are safe
    20  // and direct, but writes would create a state where the cached values are
    21  // invalid.
    22  //
    23  // This happens when mixing AppEngine datastore/memcache with Cloud Datastore
    24  // readers.
    25  package readonly