Allow a retention policy to be passed when writing points.

README.md

@@ -226,10 +226,10 @@ Write data with time precision (precision can be set in 2 ways):
 ``` ruby
 require 'influxdb'
 
-username = 'foo'
-password = 'bar'
-database = 'site_development'
-name     = 'foobar'
+username       = 'foo'
+password       = 'bar'
+database       = 'site_development'
+name           = 'foobar'
 time_precision = 's'
 
 # either in the client initialization:
@@ -249,6 +249,31 @@ influxdb.write_point(name, data, time_precision)
 
 ```
 
+Write data with a specific retention policy:
+
+``` ruby
+require 'influxdb'
+
+username  = 'foo'
+password  = 'bar'
+database  = 'site_development'
+name      = 'foobar'
+precision = 's'
+retention = '1h.cpu'
+
+influxdb = InfluxDB::Client.new database,
+                                username: username,
+                                password: password
+
+data = {
+  values: { value: 0 },
+  tags: { foo: 'bar', bar: 'baz' }
+  timestamp: Time.now.to_i
+}
+
+influxdb.write_point(name, data, precision, retention)
+```
+
 Write multiple points in a batch (performance boost):
 
 ``` ruby
@@ -274,7 +299,29 @@ influxdb.write_points(data, precision)
 
 ```
 
-Write asynchronously:
+Write multiple points in a batch with a specific retention policy:
+
+``` ruby
+
+data = [
+  {
+    series: 'cpu',
+    tags: { host: 'server_1', regios: 'us' },
+    values: {internal: 5, external: 0.453345}
+  },
+  {
+    series: 'gpu',
+    values: {value: 0.9999},
+  }
+]
+
+precision = 'm'
+retention = '1h.cpu'
+influxdb.write_points(data, precision, retention)
+
+```
+
+Write asynchronously (note that a retention policy cannot be specified for asynchronous writes):
 
 ``` ruby
 require 'influxdb'
@@ -283,7 +330,6 @@ username = 'foo'
 password = 'bar'
 database = 'site_development'
 name     = 'foobar'
-time_precision = 's'
 
 influxdb = InfluxDB::Client.new database,
                                 username: username,
@@ -299,7 +345,7 @@ data = {
 influxdb.write_point(name, data)
 ```
 
-Write data via UDP:
+Write data via UDP (note that a retention policy cannot be specified for UDP writes):
 
 ``` ruby
 require 'influxdb'

lib/influxdb/query/core.rb

@@ -37,21 +37,23 @@ def query(query, opts = {})
       #     values: {value: 0.9999},
       #   }
       # ])
-      def write_points(data, precision = nil)
+      def write_points(data, precision = nil, retention_policy = nil)
         data = data.is_a?(Array) ? data : [data]
         payload = generate_payload(data)
-        writer.write(payload, precision)
+        writer.write(payload, precision, retention_policy)
       end
 
       # Example:
       # write_point('cpu', tags: {region: 'us'}, values: {internal: 60})
-      def write_point(series, data, precision = nil)
-        write_points(data.merge(series: series), precision)
+      def write_point(series, data, precision = nil, retention_policy = nil)
+        write_points(data.merge(series: series), precision, retention_policy)
       end
 
-      def write(data, precision)
+      def write(data, precision, retention_policy = nil)
         precision ||= config.time_precision
-        url = full_url("/write", db: config.database, precision: precision)
+        params      = { db: config.database, precision: precision }
+        params[:rp] = retention_policy if retention_policy
+        url = full_url("/write", params)
         post(url, data)
       end
 

lib/influxdb/writer/async.rb

@@ -12,7 +12,7 @@ def initialize(client, config)
         @config = config
       end
 
-      def write(data, _precision = nil)
+      def write(data, _precision = nil, _retention_policy = nil)
         data = data.is_a?(Array) ? data : [data]
         data.map { |p| worker.push(p) }
       end

lib/influxdb/writer/udp.rb

@@ -13,7 +13,7 @@ def initialize(client, config)
         socket.connect(host, port)
       end
 
-      def write(payload, _precision = nil)
+      def write(payload, _precision = nil, _retention_policy = nil)
         socket.send(payload, 0)
       end
     end

spec/influxdb/cases/write_points_spec.rb

@@ -143,5 +143,35 @@
         expect(subject.write_points(data, 'm')).to be_a(Net::HTTPOK)
       end
     end
+
+    context "with retention policy" do
+      let(:data) do
+        [{
+          series: 'cpu',
+          values: { temp: 88,  value: 54 }
+        },
+         {
+           series: 'gpu',
+           values: { value: 0.5435345 }
+         }]
+      end
+
+      let(:body) do
+        data.map do |point|
+          InfluxDB::PointValue.new(point).dump
+        end.join("\n")
+      end
+
+      before do
+        stub_request(:post, "http://influxdb.test:9999/write").with(
+          query: { u: "username", p: "password", precision: 's', db: database, rp: 'rp_1_hour' },
+          headers: { "Content-Type" => "application/octet-stream" },
+          body: body
+        )
+      end
+      it "should POST multiple points" do
+        expect(subject.write_points(data, nil, 'rp_1_hour')).to be_a(Net::HTTPOK)
+      end
+    end
   end
 end