Add Json verifier

This patch adds Json verifier to the list of built-in verifiers. Json verifier
can be used with symbol ':json' on `file` like resources such as `file`,
`template` etc.

Signed-off-by: Antony Deepak Thomas <antonydeepak@gmail.com>

3 files changed, 119 insertions, 0 deletions

diff --git a/lib/chef/provider/file.rb b/lib/chef/provider/file.rb
index 8f77cc4641..4ac86a6c8a 100644
--- a/lib/chef/provider/file.rb
+++ b/lib/chef/provider/file.rb
@@ -27,6 +27,7 @@ require_relative "../scan_access_control"
 require_relative "../mixin/checksum"
 require_relative "../mixin/file_class"
 require_relative "../mixin/enforce_ownership_and_permissions"
+require_relative "../resource/file/verification/json"
 require_relative "../resource/file/verification/yaml"
 require_relative "../util/backup"
 require_relative "../util/diff"
diff --git a/lib/chef/resource/file/verification/json.rb b/lib/chef/resource/file/verification/json.rb
new file mode 100644
index 0000000000..c71e6a265e
--- /dev/null
+++ b/lib/chef/resource/file/verification/json.rb
@@ -0,0 +1,52 @@
+#
+# Author:: Antony Thomas (<antonydeepak@gmail.com>)
+# Copyright:: Copyright (c) Chef Software Inc.
+# License:: Apache License, Version 2.0
+#
+# 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" unless defined?(JSON)
+
+class Chef
+  class Resource
+    class File
+      class Verification
+
+        #
+        # Extends File verification to provide Json verification
+        #
+        # Example:
+        # file 'foo.json' do
+        #   content '{"foo": "bar"}'
+        #   verify :json
+        # end
+        #
+        #
+
+        class Json < Chef::Resource::File::Verification
+
+          provides :json
+
+          def verify(path, opts = {})
+            JSON.parse(IO.read(path))
+            true
+          rescue JSON::ParserError => e
+            Chef::Log.error("Json syntax verify failed with : #{e.message}")
+            false
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/unit/resource/file/verification/json_spec.rb b/spec/unit/resource/file/verification/json_spec.rb
new file mode 100644
index 0000000000..22a769054d
--- /dev/null
+++ b/spec/unit/resource/file/verification/json_spec.rb
@@ -0,0 +1,66 @@
+#
+# Author:: Antony Thomas (<antonydeepak@gmail.com>)
+# Copyright:: Copyright (c) Chef Software Inc.
+# License:: Apache License, Version 2.0
+#
+# 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"
+
+describe Chef::Resource::File::Verification::Json do
+  let(:parent_resource) { Chef::Resource.new("llama") }
+
+  before(:all) do
+    @valid_json = "valid-#{Time.now.to_i}.json"
+    f = File.new(@valid_json, "w")
+    f.write('{
+      "foo": "bar"
+    }')
+    f.close
+
+    @invalid_json = "invalid-#{Time.now.to_i}.json"
+    f = File.new(@invalid_json, "w")
+    f.write("{
+      'foo': 'bar'
+    }")
+    f.close
+
+    @empty_json = "empty-#{Time.now.to_i}.json"
+    File.new(@empty_json, "w").close
+  end
+
+  context "verify" do
+    it "returns true for valid json" do
+      v = Chef::Resource::File::Verification::Json.new(parent_resource, :json, {})
+      expect(v.verify(@valid_json)).to eq(true)
+    end
+
+    it "returns false for invalid json" do
+      v = Chef::Resource::File::Verification::Json.new(parent_resource, :json, {})
+      expect(v.verify(@invalid_json)).to eq(false)
+    end
+
+    it "returns false for empty file" do
+      # empty string is invalid per JSON spec https://stackoverflow.com/questions/30621802/why-does-json-parse-fail-with-the-empty-string
+      v = Chef::Resource::File::Verification::Json.new(parent_resource, :json, {})
+      expect(v.verify(@empty_json)).to eq(false)
+    end
+  end
+
+  after(:all) do
+    File.delete(@valid_json)
+    File.delete(@invalid_json)
+    File.delete(@empty_json)
+  end
+end