Files
hydra/src/libhydra/db.hh
Jörg Thalheim 5187992c94 Migrate from deprecated notification_receiver to connection::listen()
libpqxx 7.10.1 deprecates the notification_receiver class.
2025-09-07 22:48:40 -04:00

51 lines
1.1 KiB
C++

#pragma once
#include <pqxx/pqxx>
#include <nix/util/environment-variables.hh>
#include <nix/util/util.hh>
struct Connection : pqxx::connection
{
Connection() : pqxx::connection(getFlags()) { };
std::string getFlags()
{
using namespace nix;
auto s = getEnv("HYDRA_DBI").value_or("dbi:Pg:dbname=hydra;");
std::string lower_prefix = "dbi:Pg:";
std::string upper_prefix = "DBI:Pg:";
if (hasPrefix(s, lower_prefix) || hasPrefix(s, upper_prefix)) {
return concatStringsSep(" ", tokenizeString<Strings>(std::string(s, lower_prefix.size()), ";"));
}
throw Error("$HYDRA_DBI does not denote a PostgreSQL database");
}
};
class receiver
{
std::optional<std::string> status;
pqxx::connection & conn;
public:
receiver(pqxx::connection_base & c, const std::string & channel)
: conn(static_cast<pqxx::connection &>(c))
{
conn.listen(channel, [this](pqxx::notification n) {
status = std::string(n.payload);
});
}
std::optional<std::string> get() {
auto s = status;
status = std::nullopt;
return s;
}
};