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// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include <vespa/vespalib/util/gencnt.h>
#include <vespa/slobrok/backoff.h>
#include <vespa/fnet/frt/invoker.h>
class FRT_Target;
namespace slobrok::api {
/**
* @brief Defines an interface for the name server lookup.
**/
class IMirrorOld {
protected:
static bool match(const char *name, const char *pattern);
public:
/**
* @brief Release any allocated resources.
**/
virtual ~IMirrorOld() { }
/**
* @brief vector of <name, connectionspec> pairs.
*
* The first element of each pair is a string containing the
* service name. The second is the connection spec, typically
* "tcp/foo.bar.com:42"
**/
typedef std::vector< std::pair<std::string, std::string> > SpecList;
/**
* Obtain all the services matching a given pattern.
*
* The pattern is matched against all service names in the local
* mirror repository. A service name may contain '/' as a
* separator token. A pattern may contain '*' to match anything up
* to the next '/' (or the end of the name). This means that the
* pattern 'foo/<!-- slash-star -->*<!-- star-slash -->/baz' would
* match the service names 'foo/bar/baz' and 'foo/xyz/baz'. The
* pattern 'foo/b*' would match 'foo/bar', but neither 'foo/xyz'
* nor 'foo/bar/baz'. The pattern 'a*b' will never match anything.
*
* @return a list of all matching services, with corresponding connect specs
* @param pattern The pattern used for matching
**/
virtual SpecList lookup(const std::string & pattern) const = 0;
/**
* Obtain the number of updates seen by this mirror. The value may
* wrap, but will never become 0 again. This can be used for name
* lookup optimization, because the results returned by lookup()
* will never change unless this number also changes.
*
* @return number of slobrok updates seen
**/
virtual uint32_t updates() const = 0;
};
/**
* @brief A MirrorOld object is used to keep track of the services
* registered with a slobrok cluster.
*
* Updates to the service repository are fetched in the
* background. Lookups against this object is done using an internal
* mirror of the service repository.
**/
class MirrorOld : public FNET_Task,
public FRT_IRequestWait,
public IMirrorOld
{
public:
/**
* @brief Create a new MirrorOld using the given Supervisor and slobrok
* connect specs.
*
* @param orb the Supervisor to use
* @param slobroks slobrok connect spec list
**/
MirrorOld(FRT_Supervisor &orb, const std::vector<std::string> &slobroks);
/**
* @brief Clean up.
**/
~MirrorOld();
SpecList lookup(const std::string & pattern) const override;
uint32_t updates() const override { return _updates.getAsInt(); }
/**
* @brief Ask if the MirrorOld has got any useful information from
* the Slobrok
*
* On application startup it is often useful to run the event loop
* for some time until this functions returns true (or if it never
* does, time out and tell the user there was no answer from any
* Service Location Broker).
*
* @return true if the MirrorOld object has
* asked for updates from a Slobrok and got any answer back
**/
bool ready() const { return _updates.getAsInt() != 0; }
private:
MirrorOld(const MirrorOld &);
MirrorOld &operator=(const MirrorOld &);
void PerformTask() override;
void RequestDone(FRT_RPCRequest *req) override;
FRT_Supervisor &_orb;
mutable std::mutex _lock;
bool _reqDone;
SpecList _specs;
vespalib::GenCnt _specsGen;
vespalib::GenCnt _updates;
std::vector<std::string> _slobrokspecs;
uint32_t _idx;
BackOff _backOff;
FRT_Target *_target;
FRT_RPCRequest *_req;
};
} // namespace slobrok::api
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