Line data    Source code

       1             : #include "source/common/upstream/subset_lb_config.h"
       2             : 
       3             : #include "source/common/config/utility.h"
       4             : 
       5             : namespace Envoy {
       6             : namespace Upstream {
       7             : 
       8             : SubsetSelectorImpl::SubsetSelectorImpl(
       9             :     const Protobuf::RepeatedPtrField<std::string>& selector_keys,
      10             :     envoy::config::cluster::v3::Cluster::LbSubsetConfig::LbSubsetSelector::
      11             :         LbSubsetSelectorFallbackPolicy fallback_policy,
      12             :     const Protobuf::RepeatedPtrField<std::string>& fallback_keys_subset,
      13             :     bool single_host_per_subset)
      14             :     : selector_keys_(selector_keys.begin(), selector_keys.end()),
      15             :       fallback_keys_subset_(fallback_keys_subset.begin(), fallback_keys_subset.end()),
      16           0 :       fallback_policy_(fallback_policy), single_host_per_subset_(single_host_per_subset) {
      17             : 
      18           0 :   if (fallback_policy_ !=
      19           0 :       envoy::config::cluster::v3::Cluster::LbSubsetConfig::LbSubsetSelector::KEYS_SUBSET) {
      20             :     // defining fallback_keys_subset_ for a fallback policy other than KEYS_SUBSET doesn't have
      21             :     // any effect and it is probably a user mistake. We should let the user know about it.
      22           0 :     if (!fallback_keys_subset_.empty()) {
      23           0 :       throwEnvoyExceptionOrPanic(
      24           0 :           "fallback_keys_subset can be set only for KEYS_SUBSET fallback_policy");
      25           0 :     }
      26           0 :     return;
      27           0 :   }
      28             : 
      29             :   // if KEYS_SUBSET fallback policy is selected, fallback_keys_subset must not be empty, because
      30             :   // it would be the same as not defining fallback policy at all (global fallback policy would be
      31             :   // used)
      32           0 :   if (fallback_keys_subset_.empty()) {
      33           0 :     throwEnvoyExceptionOrPanic("fallback_keys_subset cannot be empty");
      34           0 :   }
      35             : 
      36             :   // We allow only for a fallback to a subset of the selector keys because this is probably the
      37             :   // only use case that makes sense (fallback from more specific selector to less specific
      38             :   // selector). Potentially we can relax this constraint in the future if there will be a use case
      39             :   // for this.
      40           0 :   if (!std::includes(selector_keys_.begin(), selector_keys_.end(), fallback_keys_subset_.begin(),
      41           0 :                      fallback_keys_subset_.end())) {
      42           0 :     throwEnvoyExceptionOrPanic("fallback_keys_subset must be a subset of selector keys");
      43           0 :   }
      44             : 
      45             :   // Enforce that the fallback_keys_subset_ set is smaller than the selector_keys_ set. Otherwise
      46             :   // we could end up with a infinite recursion of SubsetLoadBalancer::chooseHost().
      47           0 :   if (selector_keys_.size() == fallback_keys_subset_.size()) {
      48           0 :     throwEnvoyExceptionOrPanic("fallback_keys_subset cannot be equal to keys");
      49           0 :   }
      50           0 : }
      51             : 
      52             : } // namespace Upstream
      53             : } // namespace Envoy