o NDik@spddlmZddlmZddlmZmZmZmZddl Z ddl m Z m Z ddl mZddlZddlZe eZddlmZeZddlmZmZGd d d eZGd d d eZGd ddeZGdddeZGdddeZGdddeZGdddeZ GdddeZ!GdddeZ"Gddde"Z#GdddeZ$Gdd d e$Z%Gd!d"d"e$Z&Gd#d$d$eZ'Gd%d&d&e'Z(Gd'd(d(e'Z)Gd)d*d*eZ*Gd+d,d,e*Z+Gd-d.d.e*Z,Gd/d0d0eZ-Gd1d2d2eZ.Gd3d4d4e.Z/Gd5d6d6e-Z0Gd7d8d8e-Z1Gd9d:d:eZ2Gd;d<dd>e3Z4Gd?d@d@e'Z5edAgdBZ6GdCdDdDeZ7dS)E) namedtuple) lru_cache)islicecyclegroupbyrepeatN)randintshuffle)Lock) WriteType)ConsistencyLevelOperationTimedOutc@s eZdZdZdZ dZ dZdS) HostDistancez A measure of how "distant" a node is from the client, which may influence how the load balancer distributes requests and how many connections are opened to the node. rN)__name__ __module__ __qualname____doc__IGNOREDLOCALREMOTErrK/var/www/Datamplify/venv/lib/python3.10/site-packages/cassandra/policies.pyr#s rc@s,eZdZddZddZddZddZd S) HostStateListenercCt)z" Called when a node is marked up. NotImplementedErrorselfhostrrron_upIzHostStateListener.on_upcCr)z$ Called when a node is marked down. rrrrron_downMr"zHostStateListener.on_downcCr)zt Called when a node is added to the cluster. The newly added node should be considered up. rrrrron_addQzHostStateListener.on_addcCr)z1 Called when a node is removed from the cluster. rrrrr on_removeXr"zHostStateListener.on_removeN)rrrr!r#r$r&rrrrrGs  rc@s>eZdZdZdZddZddZddZd d d Zd d Z dS)LoadBalancingPolicya Load balancing policies are used to decide how to distribute requests among all possible coordinator nodes in the cluster. In particular, they may focus on querying "near" nodes (those in a local datacenter) or on querying nodes who happen to be replicas for the requested data. You may also use subclasses of :class:`.LoadBalancingPolicy` for custom behavior. NcCs t|_dSN)r _hosts_lockrrrr__init__l zLoadBalancingPolicy.__init__cCr)z Returns a measure of how remote a :class:`~.pool.Host` is in terms of the :class:`.HostDistance` enums. rrrrrdistanceor%zLoadBalancingPolicy.distancecCr)z This method is called to initialize the load balancing policy with a set of :class:`.Host` instances before its first use. The `cluster` parameter is an instance of :class:`.Cluster`. rrclusterhostsrrrpopulatevzLoadBalancingPolicy.populatecCr)a Given a :class:`~.query.Statement` instance, return a iterable of :class:`.Host` instances which should be queried in that order. A generator may work well for custom implementations of this method. Note that the `query` argument may be :const:`None` when preparing statements. `working_keyspace` should be the string name of the current keyspace, as set through :meth:`.Session.set_keyspace()` or with a ``USE`` statement. r)rworking_keyspacequeryrrrmake_query_plansz#LoadBalancingPolicy.make_query_plancCdS)a This will be called after the cluster Metadata has been initialized. If the load balancing policy implementation cannot be supported for some reason (such as a missing C extension), this is the point at which it should raise an exception. Nrr*rrrcheck_supportedsz#LoadBalancingPolicy.check_supportedNN) rrrrr)r+r-r1r5r7rrrrr']s  r'c@sVeZdZdZedZdZddZddZdd d Z d d Z d dZ ddZ ddZ dS)RoundRobinPolicyz A subclass of :class:`.LoadBalancingPolicy` which evenly distributes queries across all nodes in the cluster, regardless of what datacenter the nodes may be in. rrcCs2t||_t|dkrtdt|d|_dSdS)Nrr) frozenset _live_hostslenr _positionr.rrrr1s  zRoundRobinPolicy.populatecCstjSr()rrrrrrr-zRoundRobinPolicy.distanceNcCsF|j}|jd7_|j}t|}|r!||;}tt||||SgS)Nr)r=r;r<rr)rr3r4posr0lengthrrrr5sz RoundRobinPolicy.make_query_plancC<|j|j|f|_WddS1swYdSr(r)r;unionrrrrr!"zRoundRobinPolicy.on_upcCrAr(r)r; differencerrrrr#rDzRoundRobinPolicy.on_downcCrAr(rBrrrrr$rDzRoundRobinPolicy.on_addcCrAr(rErrrrr&rDzRoundRobinPolicy.on_remover8)rrrrr:r;r=r1r-r5r!r#r$r&rrrrr9s  r9c@sdeZdZdZdZdZdddZddZd d Zd d Z dd dZ ddZ ddZ ddZ ddZdS)DCAwareRoundRobinPolicyz Similar to :class:`.RoundRobinPolicy`, but prefers hosts in the local datacenter and only uses nodes in remote datacenters as a last resort. NrcCs,||_||_i|_d|_g|_t|dS)a The `local_dc` parameter should be the name of the datacenter (such as is reported by ``nodetool ring``) that should be considered local. If not specified, the driver will choose a local_dc based on the first host among :attr:`.Cluster.contact_points` having a valid DC. If relying on this mechanism, all specified contact points should be nodes in a single, local DC. `used_hosts_per_remote_dc` controls how many nodes in each remote datacenter will have connections opened against them. In other words, `used_hosts_per_remote_dc` hosts will be considered :attr:`~.HostDistance.REMOTE` and the rest will be considered :attr:`~.HostDistance.IGNORED`. By default, all remote hosts are ignored. rN)local_dcused_hosts_per_remote_dc_dc_live_hostsr= _endpointsr'r+)rrIrJrrrr+s z DCAwareRoundRobinPolicy.__init__cCs |jp|jSr() datacenterrIrrrr_dcr,zDCAwareRoundRobinPolicy._dccslt|fddD] \}}tt|j|<q js#dd|jD_|r1tdt|d_ dSd_ dS)Ncs |Sr()rN)hr*rrs z2DCAwareRoundRobinPolicy.populate..cSsg|]}|qSrr).0endpointrrr sz4DCAwareRoundRobinPolicy.populate..rr) rtuplesetrKrIendpoints_resolvedrLrr<r=)rr/r0dcdc_hostsrr*rr1s&z DCAwareRoundRobinPolicy.populatecCs^||}||jkr tjS|jstjS|j|}|stjS|t|d|jvr,tj StjSr() rNrIrrrJrrKgetlistr)rr rWrXrrrr-s   z DCAwareRoundRobinPolicy.distancec #sj}jd7_jjd}|r|t|nd}tt|||t|D]}|Vq)fddjD}|D]}j|d}|dj D]}|VqOq?dS)Nrrrcsg|] }|jkr|qSr)rI)rQrWr*rrrSsz;DCAwareRoundRobinPolicy.make_query_plan..) r=rKrYrIr<rrcopykeysrJ) rr3r4r? local_liver other_dcsrW remote_liverr*rr5 sz'DCAwareRoundRobinPolicy.make_query_plancCs|js|jr|j|jvr|j|_td|j|jf|`||}|j$|j |d}||vrA||f|j|<WddSWddS1sLwYdS)NzUsing datacenter '%s' for DCAwareRoundRobinPolicy (via host '%s'); if incorrect, please specify a local_dc to the constructor, or limit contact points to local cluster nodesr) rIrMrRrLloginforNr)rKrY)rr rW current_hostsrrrr!s    "zDCAwareRoundRobinPolicy.on_upcs|}|j;|j|d}|vr3tfdd|D}|r'||j|<n|j|=WddSWddSWddS1sFwYdS)Nrc3s|] }|kr|VqdSr(rrQrOr rr 2sz2DCAwareRoundRobinPolicy.on_down..)rNr)rKrYrT)rr rWrbr0rrdrr#-s   "zDCAwareRoundRobinPolicy.on_downcC||dSr()r!rrrrr$8zDCAwareRoundRobinPolicy.on_addcCrfr()r#rrrrr&;rgz!DCAwareRoundRobinPolicy.on_remove)rHrr8)rrrrrIrJr+rNr1r-r5r!r#r$r&rrrrrGs   rGc@sjeZdZdZdZdZdZ dddZddZdd Z d d Z dd d Z ddZ ddZ ddZddZdS)TokenAwarePolicya A :class:`.LoadBalancingPolicy` wrapper that adds token awareness to a child policy. This alters the child policy's behavior so that it first attempts to send queries to :attr:`~.HostDistance.LOCAL` replicas (as determined by the child policy) based on the :class:`.Statement`'s :attr:`~.Statement.routing_key`. If :attr:`.shuffle_replicas` is truthy, these replicas will be yielded in a random order. Once those hosts are exhausted, the remaining hosts in the child policy's query plan will be used in the order provided by the child policy. If no :attr:`~.Statement.routing_key` is set on the query, the child policy's query plan will be used as is. NFcC||_||_dSr() _child_policyshuffle_replicas)r child_policyrkrrrr+W zTokenAwarePolicy.__init__cC|j|_|j||dSr(metadata_cluster_metadatarjr1r.rrrr1[zTokenAwarePolicy.populatecCs&|jstd|jj|jjfdS)Nz%s cannot be used with the cluster partitioner (%s) because the relevant C extension for this driver was not compiled. See the installation instructions for details on building and installing the C extensions.)rqcan_support_partitioner RuntimeError __class__r partitionerr*rrrr7_s z TokenAwarePolicy.check_supportedcO|jj|i|Sr(rjr-rargskwargsrrrr-hzTokenAwarePolicy.distancec cs|r |jr |j}n|}|j}|dur!|||D]}|VqdS|j}|dus,|dur:|||D]}|Vq2dS|j||}|jrHt||D]}|jrZ| |t j krZ|VqJ|||D]}||vso| |t j krr|VqadSr() keyspacerjr5 routing_keyrq get_replicasrkr is_upr-rrr) rr3r4r}childr r~replicasreplicarrrr5ks8 z TokenAwarePolicy.make_query_plancOrwr(rjr!ryrrrr!r|zTokenAwarePolicy.on_upcOrwr(rjr#ryrrrr#r|zTokenAwarePolicy.on_downcOrwr(rjr$ryrrrr$r|zTokenAwarePolicy.on_addcOrwr(rjr&ryrrrr&r|zTokenAwarePolicy.on_remove)Fr8)rrrrrjrqrkr+r1r7r-r5r!r#r$r&rrrrrh?s   rhc@8eZdZdZddZddZddZdd Zd d Zd S) WhiteListRoundRobinPolicya A subclass of :class:`.RoundRobinPolicy` which evenly distributes queries across all nodes in the cluster, regardless of what datacenter the nodes may be in, but only if that node exists in the list of allowed nodes This policy is addresses the issue described in https://datastax-oss.atlassian.net/browse/JAVA-145 Where connection errors occur when connection attempts are made to private IP addresses remotely cCs*t||_dd|jD|_t|dS)zg The `hosts` parameter should be a sequence of hosts to permit connections to. cSs2g|]}t|dtjtjD]}|ddqqS)Nr)socket getaddrinfo AF_UNSPEC SOCK_STREAM)rQarRrrrrSs z6WhiteListRoundRobinPolicy.__init__..N)rT_allowed_hosts_allowed_hosts_resolvedr9r+)rr0rrrr+s z"WhiteListRoundRobinPolicy.__init__csFtfdd|D_t|dkrd_dStdt|d_dS)Nc3s |] }|jjvr|VqdSr()addressrrcr*rrresz5WhiteListRoundRobinPolicy.populate..rr)r:r;r<r=rr.rr*rr1s  z"WhiteListRoundRobinPolicy.populatecCs|j|jvr tjStjSr()rrrrrrrrrr-s z"WhiteListRoundRobinPolicy.distancecC |j|jvrt||dSdSr()rrr9r!rrrrr! zWhiteListRoundRobinPolicy.on_upcCrr()rrr9r$rrrrr$rz WhiteListRoundRobinPolicy.on_addN) rrrrr+r1r-r!r$rrrrrs   rcsneZdZdZfddZddZddZdd Zd d Ze d d Z ddZ ddZ dddZ ddZZS)HostFilterPolicyal A :class:`.LoadBalancingPolicy` subclass configured with a child policy, and a single-argument predicate. This policy defers to the child policy for hosts where ``predicate(host)`` is truthy. Hosts for which ``predicate(host)`` is falsy will be considered :attr:`.IGNORED`, and will not be used in a query plan. This can be used in the cases where you need a whitelist or blacklist policy, e.g. to prepare for decommissioning nodes or for testing: .. code-block:: python def address_is_ignored(host): return host.address in [ignored_address0, ignored_address1] blacklist_filter_policy = HostFilterPolicy( child_policy=RoundRobinPolicy(), predicate=address_is_ignored ) cluster = Cluster( primary_host, load_balancing_policy=blacklist_filter_policy, ) See the note in the :meth:`.make_query_plan` documentation for a caveat on how wrapping ordering polices (e.g. :class:`.RoundRobinPolicy`) may break desirable properties of the wrapped policy. Please note that whitelist and blacklist policies are not recommended for general, day-to-day use. You probably want something like :class:`.DCAwareRoundRobinPolicy`, which prefers a local DC but has fallbacks, over a brute-force method like whitelisting or blacklisting. cstt|||_||_dS)a| :param child_policy: an instantiated :class:`.LoadBalancingPolicy` that this one will defer to. :param predicate: a one-parameter function that takes a :class:`.Host`. If it returns a falsy value, the :class:`.Host` will be :attr:`.IGNORED` and not returned in query plans. N)superrr+rj _predicate)rrl predicaterurrr+s zHostFilterPolicy.__init__cO|jj|g|Ri|Sr(rrr rzr{rrrr!zHostFilterPolicy.on_upcOrr(rrrrrr#rzHostFilterPolicy.on_downcOrr(rrrrrr$rzHostFilterPolicy.on_addcOrr(rrrrrr&rzHostFilterPolicy.on_removecCs|jS)a A predicate, set on object initialization, that takes a :class:`.Host` and returns a value. If the value is falsy, the :class:`.Host` is :class:`~HostDistance.IGNORED`. If the value is truthy, :class:`.HostFilterPolicy` defers to the child policy to determine the host's distance. This is a read-only value set in ``__init__``, implemented as a ``property``. )rr*rrrrs zHostFilterPolicy.predicatecCs||r |j|StjS)z Checks if ``predicate(host)``, then returns :attr:`~HostDistance.IGNORED` if falsy, and defers to the child policy otherwise. )rrjr-rrrrrrr-s  zHostFilterPolicy.distancecCs|jj||ddS)N)r/r0rjr1r.rrrr1szHostFilterPolicy.populateNccs0|jj||d}|D] }||r|Vq dS)aw Defers to the child policy's :meth:`.LoadBalancingPolicy.make_query_plan` and filters the results. Note that this filtering may break desirable properties of the wrapped policy in some cases. For instance, imagine if you configure this policy to filter out ``host2``, and to wrap a round-robin policy that rotates through three hosts in the order ``host1, host2, host3``, ``host2, host3, host1``, ``host3, host1, host2``, repeating. This policy will yield ``host1, host3``, ``host3, host1``, ``host3, host1``, disproportionately favoring ``host3``. )r3r4N)rjr5r)rr3r4child_qpr rrrr5s  z HostFilterPolicy.make_query_plancCs |jSr()rjr7r*rrrr71 z HostFilterPolicy.check_supportedr8)rrrrr+r!r#r$r&propertyrr-r1r5r7 __classcell__rrrrrs #    rc@s(eZdZdZddZddZddZdS) ConvictionPolicyz A policy which decides when hosts should be considered down based on the types of failures and the number of failures. If custom behavior is needed, this class may be subclassed. cCs ||_dS)z: `host` is an instance of :class:`.Host`. Nrdrrrrr+=s zConvictionPolicy.__init__cCr)z Implementations should return :const:`True` if the host should be convicted, :const:`False` otherwise. rrconnection_excrrr add_failureCr%zConvictionPolicy.add_failurecCr)zg Implementations should clear out any convictions or state regarding the host. rr*rrrresetJr%zConvictionPolicy.resetN)rrrrr+rrrrrrr5s  rc@s eZdZdZddZddZdS)SimpleConvictionPolicyz The default implementation of :class:`ConvictionPolicy`, which simply marks a host as down after the first failure of any kind. cCs t|t Sr() isinstancer rrrrrYr,z"SimpleConvictionPolicy.add_failurecCsdSr(rr*rrrr\zSimpleConvictionPolicy.resetN)rrrrrrrrrrrRs rc@eZdZdZddZdS)ReconnectionPolicyz This class and its subclasses govern how frequently an attempt is made to reconnect to nodes that are marked as dead. If custom behavior is needed, this class may be subclassed. cCr)a% This should return a finite or infinite iterable of delays (each as a floating point number of seconds) in-between each failed reconnection attempt. Note that if the iterable is finite, reconnection attempts will cease once the iterable is exhausted. rr*rrr new_schedulehr2zReconnectionPolicy.new_scheduleN)rrrrrrrrrr`s rc@s"eZdZdZdddZddZdS) ConstantReconnectionPolicyzz A :class:`.ReconnectionPolicy` subclass which sleeps for a fixed delay in-between each reconnection attempt. @cCs8|dkrtd|dur|dkrtd||_||_dS)a( `delay` should be a floating point number of seconds to wait in-between each attempt. `max_attempts` should be a total number of attempts to be made before giving up, or :const:`None` to continue reconnection attempts forever. The default is 64. rzdelay must not be negativeN!max_attempts must not be negative) ValueErrordelay max_attemptsrrrrrrr+xs   z#ConstantReconnectionPolicy.__init__cCs|jr t|j|jSt|jSr()rrrr*rrrrs z'ConstantReconnectionPolicy.new_scheduleNr)rrrrr+rrrrrrrs  rc@s*eZdZdZd ddZddZddZd S) ExponentialReconnectionPolicya} A :class:`.ReconnectionPolicy` subclass which exponentially increases the length of the delay in-between each reconnection attempt up to a set maximum delay. A random amount of jitter (+/- 15%) will be added to the pure exponential delay value to avoid the situations where many reconnection handlers are trying to reconnect at exactly the same time. rcCsV|dks|dkr td||krtd|dur |dkr td||_||_||_dS)a `base_delay` and `max_delay` should be in floating point units of seconds. `max_attempts` should be a total number of attempts to be made before giving up, or :const:`None` to continue reconnection attempts forever. The default is 64. rzDelays may not be negativez)Max delay must be greater than base delayNr)r base_delay max_delayr)rrrrrrrr+s  z&ExponentialReconnectionPolicy.__init__ccsd\}}|jdus||jkrG|r|jVn!z|t|jd||jVWnty6d}|jVYnw|d7}|jdus||jksdSdS)N)rFTr)rr _add_jitterminr OverflowError)ri overflowedrrrrs "  z*ExponentialReconnectionPolicy.new_schedulecCs*tdd}||d}tt|j||jS)NUsd)rrmaxrr)rvaluejitterrrrrrs  z)ExponentialReconnectionPolicy._add_jitterNr)rrrrr+rrrrrrrs   rc@sHeZdZdZdZ dZ dZ dZ ddZdd Z d d Z d d Z dS) RetryPolicya A policy that describes whether to retry, rethrow, or ignore coordinator timeout and unavailable failures. These are failures reported from the server side. Timeouts are configured by `settings in cassandra.yaml `_. Unavailable failures occur when the coordinator cannot achieve the consistency level for a request. For further information see the method descriptions below. To specify a default retry policy, set the :attr:`.Cluster.default_retry_policy` attribute to an instance of this class or one of its subclasses. To specify a retry policy per query, set the :attr:`.Statement.retry_policy` attribute to an instance of this class or one of its subclasses. If custom behavior is needed for retrying certain operations, this class may be subclassed. rrrcCs2|dkr |jdfS||kr|s|j|fS|jdfS)a This is called when a read operation times out from the coordinator's perspective (i.e. a replica did not respond to the coordinator in time). It should return a tuple with two items: one of the class enums (such as :attr:`.RETRY`) and a :class:`.ConsistencyLevel` to retry the operation at or :const:`None` to keep the same consistency level. `query` is the :class:`.Statement` that timed out. `consistency` is the :class:`.ConsistencyLevel` that the operation was attempted at. The `required_responses` and `received_responses` parameters describe how many replicas needed to respond to meet the requested consistency level and how many actually did respond before the coordinator timed out the request. `data_retrieved` is a boolean indicating whether any of those responses contained data (as opposed to just a digest). `retry_num` counts how many times the operation has been retried, so the first time this method is called, `retry_num` will be 0. By default, operations will be retried at most once, and only if a sufficient number of replicas responded (with data digests). rN)RETHROWRETRYrr4 consistencyrequired_responsesreceived_responsesdata_retrieved retry_numrrron_read_timeouts     zRetryPolicy.on_read_timeoutcCs0|dkr |jdfS|tjkr|j|fS|jdfS)a! This is called when a write operation times out from the coordinator's perspective (i.e. a replica did not respond to the coordinator in time). `query` is the :class:`.Statement` that timed out. `consistency` is the :class:`.ConsistencyLevel` that the operation was attempted at. `write_type` is one of the :class:`.WriteType` enums describing the type of write operation. The `required_responses` and `received_responses` parameters describe how many replicas needed to acknowledge the write to meet the requested consistency level and how many replicas actually did acknowledge the write before the coordinator timed out the request. `retry_num` counts how many times the operation has been retried, so the first time this method is called, `retry_num` will be 0. By default, failed write operations will retried at most once, and they will only be retried if the `write_type` was :attr:`~.WriteType.BATCH_LOG`. rN)rr BATCH_LOGrrr4r write_typerrrrrron_write_timeouts     zRetryPolicy.on_write_timeoutcCs|dkr |jdfS|jdfS)a This is called when the coordinator node determines that a read or write operation cannot be successful because the number of live replicas are too low to meet the requested :class:`.ConsistencyLevel`. This means that the read or write operation was never forwarded to any replicas. `query` is the :class:`.Statement` that failed. `consistency` is the :class:`.ConsistencyLevel` that the operation was attempted at. `required_replicas` is the number of replicas that would have needed to acknowledge the operation to meet the requested consistency level. `alive_replicas` is the number of replicas that the coordinator considered alive at the time of the request. `retry_num` counts how many times the operation has been retried, so the first time this method is called, `retry_num` will be 0. By default, if this is the first retry, it triggers a retry on the next host in the query plan with the same consistency level. If this is not the first retry, no retries will be attempted and the error will be re-raised. rN)RETRY_NEXT_HOSTrrr4rrequired_replicasalive_replicasrrrron_unavailable7szRetryPolicy.on_unavailablecCs |jdfS)a This is called when an unexpected error happens. This can be in the following situations: * On a connection error * On server errors: overloaded, isBootstrapping, serverError, etc. `query` is the :class:`.Statement` that timed out. `consistency` is the :class:`.ConsistencyLevel` that the operation was attempted at. `error` the instance of the exception. `retry_num` counts how many times the operation has been retried, so the first time this method is called, `retry_num` will be 0. By default, it triggers a retry on the next host in the query plan with the same consistency level. N)r)rr4rerrorrrrron_request_errorRs zRetryPolicy.on_request_errorN) rrrrrrIGNORErrrrrrrrrrs!! rc@s0eZdZdZddZddZddZdd Zd S) FallthroughRetryPolicyzb A retry policy that never retries and always propagates failures to the application. cO |jdfSr(rryrrrrrrz&FallthroughRetryPolicy.on_read_timeoutcOrr(rryrrrrurz'FallthroughRetryPolicy.on_write_timeoutcOrr(rryrrrrxrz%FallthroughRetryPolicy.on_unavailablecOrr(rryrrrr{rz'FallthroughRetryPolicy.on_request_errorN)rrrrrrrrrrrrrls  rcs@eZdZdZfddZddZddZdd Zd d ZZ S) !DowngradingConsistencyRetryPolicya *Deprecated:* This retry policy will be removed in the next major release. A retry policy that sometimes retries with a lower consistency level than the one initially requested. **BEWARE**: This policy may retry queries using a lower consistency level than the one initially requested. By doing so, it may break consistency guarantees. In other words, if you use this retry policy, there are cases (documented below) where a read at :attr:`~.QUORUM` *may not* see a preceding write at :attr:`~.QUORUM`. Do not use this policy unless you have understood the cases where this can happen and are ok with that. It is also recommended to subclass this class so that queries that required a consistency level downgrade can be recorded (so that repairs can be made later, etc). This policy implements the same retries as :class:`.RetryPolicy`, but on top of that, it also retries in the following cases: * On a read timeout: if the number of replicas that responded is greater than one but lower than is required by the requested consistency level, the operation is retried at a lower consistency level. * On a write timeout: if the operation is an :attr:`~.UNLOGGED_BATCH` and at least one replica acknowledged the write, the operation is retried at a lower consistency level. Furthermore, for other write types, if at least one replica acknowledged the write, the timeout is ignored. * On an unavailable exception: if at least one replica is alive, the operation is retried at a lower consistency level. The reasoning behind this retry policy is as follows: if, based on the information the Cassandra coordinator node returns, retrying the operation with the initially requested consistency has a chance to succeed, do it. Otherwise, if based on that information we know the initially requested consistency level cannot be achieved currently, then: * For writes, ignore the exception (thus silently failing the consistency requirement) if we know the write has been persisted on at least one replica. * For reads, try reading at a lower consistency level (thus silently failing the consistency requirement). In other words, this policy implements the idea that if the requested consistency level cannot be achieved, the next best thing for writes is to make sure the data is persisted, and that reading something is better than reading nothing, even if there is a risk of reading stale data. c&tt|j|i|tdtdS)Nz^DowngradingConsistencyRetryPolicy is deprecated and will be removed in the next major release.)rrr+warningswarnDeprecationWarningryrrrr+sz*DowngradingConsistencyRetryPolicy.__init__cCsF|dkr |jtjfS|dkr|jtjfS|dkr|jtjfS|jdfS)Nrrr)rr THREETWOONEr)r num_responsesrrr_pick_consistencys    z3DowngradingConsistencyRetryPolicy._pick_consistencycCsP|dkr |jdfSt|r|jdfS||kr||S|s#|j|fS|jdfSNr)rr is_serialrrrrrrrs      z1DowngradingConsistencyRetryPolicy.on_read_timeoutcCst|dkr |jdfS|tjtjtjfvr!|dkr|jdfS|jdfS|tjkr+||S|tjkr5|j |fS|jdfSr) rr SIMPLEBATCHCOUNTERrUNLOGGED_BATCHrrrrrrrrs        z2DowngradingConsistencyRetryPolicy.on_write_timeoutcCs0|dkr |jdfSt|r|jdfS||Sr)rr rrrrrrrrs     z0DowngradingConsistencyRetryPolicy.on_unavailable) rrrrr+rrrrrrrrrrs 0 rc@r)AddressTranslatora Interface for translating cluster-defined endpoints. The driver discovers nodes using server metadata and topology change events. Normally, the endpoint defined by the server is the right way to connect to a node. In some environments, these addresses may not be reachable, or not preferred (public vs. private IPs in cloud environments, suboptimal routing, etc). This interface allows for translating from server defined endpoints to preferred addresses for driver connections. *Note:* :attr:`~Cluster.contact_points` provided while creating the :class:`~.Cluster` instance are not translated using this mechanism -- only addresses received from Cassandra nodes are. cCr)zs Accepts the node ip address, and returns a translated address to be used connecting to this node. rraddrrrr translateszAddressTranslator.translateNrrrrrrrrrrs rc@r)IdentityTranslatorz2 Returns the endpoint with no translation cCs|Sr(rrrrrrrzIdentityTranslator.translateNrrrrrr rc@r)EC2MultiRegionTranslatorz Resolves private ips of the hosts in the same datacenter as the client, and public ips of hosts in other datacenters. c Csft|dtjtjdd}t|}t|d|tjD]}z |ddWSty0Yqw|S)z Reverse DNS the public broadcast_address, then lookup that hostname to get the AWS-resolved IP, which will point to the private IP address within the same datacenter. rr)rrrrgetfqdn Exception)rrfamilyr rrrrr s  z"EC2MultiRegionTranslator.translateNrrrrrrrrc@r)SpeculativeExecutionPolicyz> Interface for specifying speculative execution plans cCr)z^ Returns :param keyspace: :param statement: :return: rrr} statementrrrnew_plansz#SpeculativeExecutionPolicy.new_planN)rrrrrrrrrrs rc@eZdZddZdS)SpeculativeExecutionPlancCrr(rrrrrnext_execution+r>z'SpeculativeExecutionPlan.next_executionNrrrrrrrrr* rc@r)NoSpeculativeExecutionPlancCr6)Nrrrrrrr0rz)NoSpeculativeExecutionPlan.next_executionNrrrrrr/rrc@r)NoSpeculativeExecutionPolicycCstSr()rrrrrr6r>z%NoSpeculativeExecutionPolicy.new_planN)rrrrrrrrr4s rc@s0eZdZdZddZGdddeZddZdS) "ConstantSpeculativeExecutionPolicyz A speculative execution policy that sends a new query every X seconds (**delay**) for a maximum of Y attempts (**max_attempts**). cCrir()rrrrrrr+?rmz+ConstantSpeculativeExecutionPolicy.__init__c@seZdZddZddZdS)zCConstantSpeculativeExecutionPolicy.ConstantSpeculativeExecutionPlancCrir()r remainingrrrrr+DrmzLConstantSpeculativeExecutionPolicy.ConstantSpeculativeExecutionPlan.__init__cCs"|jdkr|jd8_|jSdS)Nrrr)rrrrrrrHs zRConstantSpeculativeExecutionPolicy.ConstantSpeculativeExecutionPlan.next_executionN)rrrr+rrrrr ConstantSpeculativeExecutionPlanCs rcCs||j|jSr()rrrrrrrrOsz+ConstantSpeculativeExecutionPolicy.new_planN)rrrrr+rrrrrrrr:s  rc@sDeZdZddZddZddZddZd d Zd d Zd dZ dS) WrapperPolicycCs ||_dSr()rj)rrlrrrr+UrzWrapperPolicy.__init__cOrwr(rxryrrrr-Xr|zWrapperPolicy.distancecCs|j||dSr(rr.rrrr1[r|zWrapperPolicy.populatecOrwr(rryrrrr!^r|zWrapperPolicy.on_upcOrwr(rryrrrr#ar|zWrapperPolicy.on_downcOrwr(rryrrrr$dr|zWrapperPolicy.on_addcOrwr(rryrrrr&gr|zWrapperPolicy.on_removeN) rrrr+r-r1r!r#r$r&rrrrrSs rc@s&eZdZdZdZddZdddZdS)DefaultLoadBalancingPolicyz A :class:`.LoadBalancingPolicy` wrapper that adds the ability to target a specific host first. If no host is set on the query, the child policy's query plan will be used as is. NcCrnr(ror.rrrr1trrz#DefaultLoadBalancingPolicy.populateccs|r |jr |j}n|}|rt|ddnd}|j|}|j}|r9|jr9|V|||D] }||kr6|Vq-dS|||D]}|Vq?dS)N target_host)r}getattrrqget_hostrjrr5)rr3r4r}rr rrOrrrr5xs"   z*DefaultLoadBalancingPolicy.make_query_planr8)rrrrrqr1r5rrrrrks rcs eZdZdZfddZZS)DSELoadBalancingPolicyz *Deprecated:* This will be removed in the next major release, consider using :class:`.DefaultLoadBalancingPolicy`. cr)NzYDSELoadBalancingPolicy will be removed in 4.0. Consider using DefaultLoadBalancingPolicy.)rr r+rrrryrrrr+szDSELoadBalancingPolicy.__init__)rrrrr+rrrrrr sr c@s eZdZddZeZeZeZdS)NeverRetryPolicycOrr(rryrrr_rethrowrzNeverRetryPolicy._rethrowN)rrrrrrrrrrrr s r ColDesc)kstablecolc@r) ColumnEncryptionPolicya A policy enabling (mostly) transparent encryption and decryption of data before it is sent to the cluster. Key materials and other configurations are specified on a per-column basis. This policy can then be used by driver structures which are aware of the underlying columns involved in their work. In practice this includes the following cases: * Prepared statements - data for columns specified by the cluster's policy will be transparently encrypted before they are sent * Rows returned from any query - data for columns specified by the cluster's policy will be transparently decrypted before they are returned to the user To enable this functionality, create an instance of this class (or more likely a subclass) before creating a cluster. This policy should then be configured and supplied to the Cluster at creation time via the :attr:`.Cluster.column_encryption_policy` attribute. cCr)a Encrypt the specified bytes using the cryptography materials for the specified column. Largely used internally, although this could also be used to encrypt values supplied to non-prepared statements in a way that is consistent with this policy. r)rcoldesc obj_bytesrrrencryptzColumnEncryptionPolicy.encryptcCr)z Decrypt the specified (encrypted) bytes using the cryptography materials for the specified column. Used internally; could be used externally as well but there's not currently an obvious use case. r)rrencrypted_bytesrrrdecryptrzColumnEncryptionPolicy.decryptcCr)z Provide cryptography materials to be used when encrypted and/or decrypting data for the specified column. r)rrkeyrrr add_columnr%z!ColumnEncryptionPolicy.add_columncCr)z Predicate to determine if a specific column is supported by this policy. Currently only used internally. r)rrrrrcontains_columnr%z&ColumnEncryptionPolicy.contains_columncCr)zp Helper function to enable use of this policy on simple (i.e. non-prepared) statements. r)rrobjrrrencode_and_encryptr%z)ColumnEncryptionPolicy.encode_and_encryptN) rrrrrrrrrrrrrrs r)8 collectionsr functoolsr itertoolsrrrrloggingrandomrr threadingr rr getLoggerrr` cassandrar WTr r objectrrr'r9rGrhrrrrrrrrrrrrrrrrrrrrr r rrrrrrsV     $<0vW/p9%k#