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// file : mod/database-module.hxx -*- C++ -*-
// license : MIT; see accompanying LICENSE file
#ifndef MOD_DATABASE_MODULE_HXX
#define MOD_DATABASE_MODULE_HXX
#include <odb/forward.hxx> // odb::core::database, odb::core::connection_ptr
#include <libbrep/types.hxx>
#include <libbrep/utility.hxx>
#include <mod/module.hxx>
#include <mod/module-options.hxx>
namespace brep
{
struct tenant_service;
// A handler that utilises the database. Specifically, it will retry the
// request in the face of recoverable database failures (deadlock, loss of
// connection, etc) up to a certain number of times.
//
class database_module: public handler
{
protected:
database_module () = default;
// Create a shallow copy (handling instance) if initialized and a deep
// copy (context exemplar) otherwise.
//
explicit
database_module (const database_module&);
// Required to avoid getting warning from clang that
// database_module::init() hides handler::init() virtual functions. This
// way all functions get to the same scope and become overloaded set.
//
using handler::init;
// Initialize the package database instance. Throw odb::exception on
// failure.
//
void
init (const options::package_db&, size_t retry);
// Initialize the build database instance. Throw odb::exception on
// database failure.
//
void
init (const options::build_db&, size_t retry);
virtual bool
handle (request&, response&) = 0;
// Helpers.
//
// Update the tenant-associated service state if the specified
// notification callback-returned function (expected to be not NULL)
// returns the new state data. Return the service state data, if updated,
// and nullopt otherwise.
//
// Specifically, start the database transaction, query the service state,
// and call the callback-returned function on this state. If this call
// returns the data string (rather than nullopt), then update the service
// state with this data and persist the change. Repeat all the above steps
// on the recoverable database failures (deadlocks, etc).
//
optional<string>
update_tenant_service_state (
const odb::core::connection_ptr&,
const string& tid,
const function<optional<string> (const tenant_service&)>&);
protected:
size_t retry_ = 0; // Max of all retries.
shared_ptr<odb::core::database> package_db_;
shared_ptr<odb::core::database> build_db_; // NULL if not building.
private:
virtual bool
handle (request&, response&, log&);
};
}
#endif // MOD_DATABASE_MODULE_HXX
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