Repository: aws/aws-xray-sdk-node (js)

Issue:
Local Sampling Rules configuration version 1 is not applied
Hello,

Local Sampling Rules configured with json version 1 do not seem to work anymore.

```
const rules = {
  "rules": [{
    "description": "test.",
    "service_name": "*",
    "http_method": "*",
    "url_path": "*",
    "fixed_target": 0,
    "rate": 1
  }],
  "default": {
    "fixed_target": 1,
    "rate": 0.1
  },
  "version": 1
  }

AWSXRay.middleware.setSamplingRules(rules);
```

Please checkout small example that rules configured with version 1 and withot version 2 are precessed in defferent ways:

https://github.com/kvzaytsev/xray-sampling

I guess that's caused by 

https://github.com/aws/aws-xray-sdk-node/blob/master/packages/core/lib/middleware/sampling/local_sampler.js#L131

```
if (config.version === 2)
  params[key] = value;
if (config.version === 1 && key === 'service_name')
  params['host'] = value;
```

if config version is `1`, only `host` field is added to the params object so `httpMethod ` and `urlPath` are not matched using Utils.wildcardMatch.

Thanks!

Pull request description:
fix: transform v1 sampling rules to v2 format
*Issue #, if available:*
Fixes #65 
*Description of changes:*
Updates the `LocalSampler` so that it copies all valid config rules to its internal rules.
The `service_name` field still gets renamed to `host` if `version` is 1.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.


Patch:
diff --git a/packages/core/lib/middleware/sampling/local_sampler.js b/packages/core/lib/middleware/sampling/local_sampler.js
index 49c6900..c340686 100644
--- a/packages/core/lib/middleware/sampling/local_sampler.js
+++ b/packages/core/lib/middleware/sampling/local_sampler.js
@@ -132,6 +132,8 @@ var parseRulesConfig = function parseRulesConfig(config) {
             params[key] = value;
           if (config.version === 1 && key === 'service_name')
             params['host'] = value;
+          else 
+            params[key] = value;
           delete required[key];
         }
       }


Test patch:
diff --git a/packages/core/test/unit/sampling/local_sampler.test.js b/packages/core/test/unit/sampling/local_sampler.test.js
index 2ec7d43..49da19c 100644
--- a/packages/core/test/unit/sampling/local_sampler.test.js
+++ b/packages/core/test/unit/sampling/local_sampler.test.js
@@ -77,6 +77,55 @@ describe('localSampler', function() {
       assert(localSampler.rules);
     });
 
+    it('should load all valid rules from custom SamplingRules object given a version 1 config', function() {
+      localSampler.rules = null;
+      var v1SamplingRules = {
+        rules: [
+          {
+            description: 'moop',
+            http_method: 'GET',
+            service_name: '*.foo.com',
+            url_path: '/signin/*',
+            fixed_target: 0,
+            rate: 0
+          },
+          {
+            description: 'noop',
+            http_method: 'POST',
+            service_name: '*.moop.com',
+            url_path: '/login/*',
+            fixed_target: 10,
+            rate: 0.05
+          }
+        ],
+        default: {
+          fixed_target: 10,
+          rate: 0.05
+        },
+        version: 1
+      };
+      localSampler.setLocalRules(v1SamplingRules);
+      var rules = localSampler.rules;
+      var rule0 = rules[0];
+      var rule1 = rules[1];
+      var rule2 = rules[2];
+
+      assert.equal(rule0.host, v1SamplingRules.rules[0].service_name);
+      assert.equal(rule0.http_method, v1SamplingRules.rules[0].http_method);
+      assert.equal(rule0.url_path, v1SamplingRules.rules[0].url_path);
+      assert.equal(rule0.description, v1SamplingRules.rules[0].description);
+      assert.instanceOf(rule0.reservoir, LocalReservoir);
+      
+      assert.equal(rule1.host, v1SamplingRules.rules[1].service_name);
+      assert.equal(rule1.http_method, v1SamplingRules.rules[1].http_method);
+      assert.equal(rule1.url_path, v1SamplingRules.rules[1].url_path);
+      assert.equal(rule1.description, v1SamplingRules.rules[1].description);
+      assert.instanceOf(rule1.reservoir, LocalReservoir);
+
+      assert.isTrue(rule2.default);
+      assert.instanceOf(rule2.reservoir, LocalReservoir);
+    });
+
     describe('given a config file', function() {
       var sandbox;