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% ============LICENSE_START=======================================================
% org.onap.dcae
% ================================================================================
% Copyright (c) 2017 AT&T Intellectual Property. All rights reserved.
% ================================================================================
% Licensed under the Apache License, Version 2.0 (the "License");
% you may not use this file except in compliance with the License.
% You may obtain a copy of the License at
%
% http://www.apache.org/licenses/LICENSE-2.0
%
% Unless required by applicable law or agreed to in writing, software
% distributed under the License is distributed on an "AS IS" BASIS,
% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
% See the License for the specific language governing permissions and
% limitations under the License.
% ============LICENSE_END=========================================================
%
% ECOMP is a trademark and service mark of AT&T Intellectual Property.
-module(consul_interface).
-export([consul_register/8,
consul_deregister/3,
consul_get_configuration/3,
consul_get_preferences/3,
consul_get_service_ip_port/3,
consul_push_config/4,
consul_push_preferences/4,
consul_bind_config/3,
consul_delete_config/3,
consul_delete_preferences/3
]).
-define(SC(L), util:concat(L)).
-define(PrefKey(Appname), ?SC([Appname, ":preferences"])).
%the Erlang library linked on the Consul webpage does not seem to be equivelent to python-consul. It does something else: https://github.com/undeadlabs/discovery
%and this one seems to be just elixer: https://github.com/undeadlabs/consul-ex
%so, for now, I'm just doing some HTTP calls directly against the REST API.
consul_get_service(XER, Appname, ConsulURL) ->
%returns a list of maps
URL = ?SC([ConsulURL, "/v1/catalog/service/", Appname]),
{200, ReturnBody} = httpabs:get(XER, URL),
jiffy:decode(ReturnBody, [return_maps]).
consul_write_kv(XER, Key, Value, ConsulURL) ->
%generic helper function to write a value into Consul
URL = ?SC([ConsulURL,"/v1/kv/", Key]),
httpabs:put(XER, URL, "application/json", Value).
consul_read_kv(XER, Key, ConsulURL) ->
%does a get on the KV store, see https://www.consul.io/docs/agent/http/kv.html
%Appname MUST be a binary not a string!
URL = ?SC([ConsulURL, "/v1/kv/", Key]),
{RC, RB} = httpabs:get(XER, URL),
case RC of
200 ->
[Drb] = jiffy:decode(RB, [return_maps]),
{200, base64:decode(maps:get(<<"Value">>, Drb))}; %NOTE! Does not do a JSON decode here in case you want to read non-JSON from Consul. Leaves the decode to the caller.
_ ->
{RC, RB}
end.
consul_delete_kv(XER, Key, ConsulURL) ->
%the config has not been jiffy'd prior to this function
URL = ?SC([ConsulURL,"/v1/kv/", Key]),
httpabs:delete(XER, URL).
%%%%%%%%%%%%%%%%%
%PUBLIC FUNCTIONS
%%%%%%%%%%%%%%%%%
consul_register(XER, Appname, ConsulURL, SDIP, SDPort, HealthURL, HCInterval, AutoDeregisterAfter) ->
%uses the agent api to register this app as a service and it's healthcheck URL, which is this broker as a proxy.
%/v1/agent/service/register from https://www.consul.io/docs/agent/http/agent.html#agent_service_register
URL = ?SC([ConsulURL, "/v1/agent/service/register"]),
Body = jiffy:encode(
{[{<<"Name">>, Appname},
{<<"Address">>, SDIP},
{<<"Port">>, SDPort},
{<<"Check">> ,
{[{<<"HTTP">>, HealthURL}, {<<"Interval">>, HCInterval}, {<<"DeregisterCriticalServiceAfter">>, AutoDeregisterAfter}]}
}
]}),
httpabs:put(XER, URL, "application/json", Body).
consul_deregister(XER, Appname, ConsulURL) ->
%/v1/agent/service/deregister/<serviceId> from https://www.consul.io/docs/agent/http/agent.html#agent_service_register
URL = ?SC([ConsulURL, "/v1/agent/service/deregister/", Appname]),
httpabs:put(XER, URL, "application/json", ""). %kinda weird that this isnt a DELETE
consul_get_configuration(XER, Appname, ConsulURL) ->
%fetch configuration from consul, assumes it is a json
%returns it as a map. can be encoded again.
{RC, RB} = consul_read_kv(XER, Appname, ConsulURL),
case RC of
200 -> {200, jiffy:decode(RB, [return_maps])}; %configuration is a JSON
_ -> {RC, RB}
end.
consul_get_preferences(XER, Appname, ConsulURL) ->
%This function is currently only used in testing and is not used in resource_handler, but could be useful later
%returns it as a map. can be encoded again.
{RC, RB} = consul_read_kv(XER, ?PrefKey(Appname), ConsulURL),
case RC of
200 -> {200, jiffy:decode(RB, [return_maps])}; %configuration is a JSON
_ -> {RC, RB}
end.
consul_get_service_ip_port(XER, Appname, ConsulURL) ->
%use when you are expecting consul_get_service to return a list of exactly one service and all you want is ip:port
M = lists:nth(1, consul_get_service(XER, Appname, ConsulURL)),
{maps:get(<<"ServiceAddress">>, M), maps:get(<<"ServicePort">>, M)}.
consul_push_config(XER, Appname, ConsulURL, Config) ->
%pushes Config into Consul under the key "Appname".
%TODO: Possibly this should be under "Appname:config" to be consistent with preferences but this came first and that's an invasive change.
%the config has not been jiffy'd prior to this function
consul_write_kv(XER, Appname, jiffy:encode(Config), ConsulURL).
consul_push_preferences(XER, Appname, ConsulURL, Preferences) ->
%pushes the preferences into Consul under the key "Appname:preferences"
%the config has not been jiffy'd prior to this function
consul_write_kv(XER, ?PrefKey(Appname), jiffy:encode(Preferences), ConsulURL).
consul_delete_config(XER, Appname, ConsulURL) ->
consul_delete_kv(XER, Appname, ConsulURL).
consul_delete_preferences(XER, Appname, ConsulURL) ->
consul_delete_kv(XER, ?PrefKey(Appname), ConsulURL).
consul_bind_config(XER, Appname, ConsulURL) ->
URL = ?SC([util:resolve_cbs(XER, ConsulURL), "/service_component/", Appname]),
{ReturnCode, ReturnBody} = httpabs:get(XER, URL),
case ReturnCode of
200 -> {200, jiffy:decode(ReturnBody)};
_ -> {ReturnCode, ReturnBody} %do not try to decode if not correct
end.
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