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%% EPMD implementation which redefines how name lookups work |
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%% There is no behaviour for erl_epmd |
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-module(mongoose_epmd). |
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-export([ |
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start/0, |
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start_link/0, |
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stop/0, |
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port_please/2, port_please/3, |
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listen_port_please/2, |
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names/0, names/1, |
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register_node/2, register_node/3, |
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address_please/3, |
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open/0, open/1, open/2 |
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]). |
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-include_lib("kernel/include/logger.hrl"). |
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%% For debugging |
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-export([lookup_ip/1]). |
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-export([match_node_name/2]). |
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|
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-type lookup_error() :: |
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{no_ip_in_db, node()} |
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| {cannot_connect_to_epmd, node(), inet:ip_address()} |
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| {no_record_for_node, node()} |
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| mongoose_node_address_ets_table_not_found. |
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|
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-ignore_xref([ |
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start/0, |
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start_link/0, |
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stop/0, |
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port_please/2, port_please/3, |
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listen_port_please/2, |
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names/0, names/1, |
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register_node/2, register_node/3, |
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address_please/3, |
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open/0, open/1, open/2, |
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lookup_ip/1, match_node_name/2 |
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]). |
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|
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:-( |
start() -> erl_epmd:start(). |
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:-( |
start_link() -> erl_epmd:start_link(). |
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:-( |
stop() -> erl_epmd:stop(). |
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:-( |
port_please(A, B) -> erl_epmd:port_please(A, B). |
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:-( |
port_please(A, B, C) -> erl_epmd:port_please(A, B, C). |
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:-( |
listen_port_please(A, B) -> erl_epmd:listen_port_please(A, B). |
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:-( |
names() -> erl_epmd:names(). |
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:-( |
names(A) -> erl_epmd:names(A). |
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:-( |
register_node(A, B) -> erl_epmd:register_node(A, B). |
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:-( |
register_node(A, B, C) -> erl_epmd:register_node(A, B, C). |
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:-( |
open() -> erl_epmd:open(). |
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:-( |
open(A) -> erl_epmd:open(A). |
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:-( |
open(A, B) -> erl_epmd:open(A, B). |
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|
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address_please(Name, Host, AddressFamily) -> |
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4 |
Node = list_to_binary(Name ++ "@" ++ Host), |
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case lookup_ip(Node) of |
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{ok, _IP} = Res -> |
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Res; |
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_ -> |
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%% Fallback to the default behaviour |
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inet:getaddr(Host, AddressFamily) |
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end. |
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|
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%% This function waits for the IP address to appear. |
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%% It only works well in case net_kernel does not contact a lot of |
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%% dead nodes. |
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%% Generally, we only expect calls for nodes that are alive |
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%% and the connect is issued by CETS (but CETS checks that node is |
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%% reachable first) or by connect_all feature in the global module of OTP. |
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-spec lookup_ip(binary()) -> {ok, inet:ip_address()} | {error, lookup_error()}. |
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lookup_ip(Node) -> |
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try |
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cets_discovery:wait_for_get_nodes(mongoose_cets_discovery, 3000), |
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cets_discovery:system_info(mongoose_cets_discovery) |
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of |
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#{backend_state := BackendState} -> |
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match_node_name(BackendState, Node) |
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catch _:_ -> |
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{error, failed_to_get_disco_state} |
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end. |
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match_node_name(#{address_pairs := Pairs}, Node) -> |
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case Pairs of |
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#{Node := <<>>} -> |
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%% The caller should try DNS. |
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{error, {no_ip_in_db, Node}}; |
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#{Node := Bin} -> |
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inet:parse_address(binary_to_list(Bin)); |
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#{} -> |
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{error, {no_record_for_node, Node}} |
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end; |
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match_node_name(BackendState, Node) -> |
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%% Could happen if CETS backend is not mongoose_cets_discovery_rdbms |
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?LOG_ERROR(#{what => cets_no_address_pairs_set, |
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backend_state => BackendState, |
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:-( |
remote_node => Node}), |
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1 |
{error, no_address_pairs_set}. |