Add support for watch.

examples/watch/watch.rb

@@ -0,0 +1,25 @@
+# Copyright 2019 The Kubernetes Authors.
+#
+# 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.
+
+require 'kubernetes'
+require 'pp'
+
+config = Kubernetes::Configuration.default_config()
+client = Kubernetes::ApiClient.new(config)
+
+watch = Kubernetes::Watch.new(client)
+
+watch.connect('/api/v1/namespaces') do |obj|
+    pp obj
+end

kubernetes/lib/kubernetes.rb

@@ -16,6 +16,7 @@
 require 'kubernetes/version'
 require 'kubernetes/configuration'
 require 'kubernetes/loader'
+require 'kubernetes/watch'
 
 # Configuration
 require 'kubernetes/config/error'

kubernetes/spec/watch_spec.rb

@@ -0,0 +1,36 @@
+# Copyright 2019 The Kubernetes Authors.
+#
+# 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.
+
+require 'spec_helper'
+require 'kubernetes/watch'
+
+describe 'WatchClient' do
+  it 'should construct correctly' do
+    Kubernetes::Watch.new(nil)
+  end
+
+  it 'should parse chunks correctly' do
+    client = Kubernetes::Watch.new(nil)
+    last = ''
+
+    last, data = client.split_lines(last, "foo\nbar\nba")
+
+    expect(last).to eq('ba')
+    expect(data).to eq(%w[foo bar])
+
+    last, data = client.split_lines(last, "z\nblah\n")
+    expect(last).to eq('')
+    expect(data).to eq(%w[baz blah])
+  end
+end

kubernetes/src/kubernetes/watch.rb

@@ -0,0 +1,51 @@
+# Copyright 2019 The Kubernetes Authors.
+#
+# 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.
+
+require 'json'
+
+# The Kubernetes module encapsulates the Kubernetes client for Ruby
+module Kubernetes
+  # The Watch class provides the ability to watch a specific resource for
+  # updates.
+  class Watch
+    def initialize(client)
+      @client = client
+    end
+
+    def connect(path, &_block)
+      opts = { auth_names: ['BearerToken'] }
+      request = @client.build_request('GET', path + '?watch=true', opts)
+      last = ''
+      request.on_body do |chunk|
+        last, pieces = split_lines(last, chunk)
+        pieces.each do |part|
+          yield JSON.parse(part)
+        end
+      end
+      request.run
+    end
+
+    def split_lines(last, chunk)
+      data = chunk
+      data = last + '' + data
+
+      ix = data.rindex("\n")
+      return [data, []] unless ix
+
+      complete = data[0..ix]
+      last = data[(ix + 1)..data.length]
+      [last, complete.split(/\n/)]
+    end
+  end
+end