fix `LOG.child(...)` to *not* override the "hostname" field of the parent

Fixes #291. Fixes #303.

AUTHORS

@@ -26,3 +26,4 @@ Denis Izmaylov (https://github.com/DenisIzmaylov)
 Guillermo Grau Panea (https://github.com/guigrpa)
 Mark LeMerise (https://github.com/MarkLeMerise)
 https://github.com/sometimesalready
+Charly Koza (https://github.com/Cactusbone)

CHANGES.md

@@ -8,6 +8,10 @@ Known issues:
 
 ## 1.5.2 (not yet released)
 
+- [pull #291, issue #303] Fix `LOG.child(...)` to *not* override the "hostname"
+  field of the parent. A use case is when one manually sets "hostname" to
+  something other than `os.hostname()`. (By github.com/Cactusbone.)
+
 - [issue #325] Allow one to set `level: 0` in `createLogger` to turn on
   logging for all levels. (Adapted from #336 by github.com/sometimesalready.)
 

lib/bunyan.js

@@ -478,7 +478,7 @@ function Logger(options, _childOptions, _childSimple) {
     if (this.serializers) {
         this._applySerializers(fields);
     }
-    if (!fields.hostname) {
+    if (!fields.hostname && !self.fields.hostname) {
         fields.hostname = os.hostname();
     }
     if (!fields.pid) {

test/child-behaviour.test.js

@@ -134,3 +134,28 @@ test('child can set level of inherited streams and add streams', function (t) {
 
     t.end();
 });
+
+// issue #291
+test('child should not lose parent "hostname"', function (t) {
+    var stream = new CapturingStream();
+    var dad = bunyan.createLogger({
+        name: 'hostname-test',
+        hostname: 'bar0',
+        streams: [ {
+            type: 'raw',
+            stream: stream,
+            level: 'info'
+        } ]
+    });
+    var son = dad.child({component: 'son'});
+
+    dad.info('HI');
+    son.info('hi');
+
+    t.equal(stream.recs.length, 2);
+    t.equal(stream.recs[0].hostname, 'bar0');
+    t.equal(stream.recs[1].hostname, 'bar0');
+    t.equal(stream.recs[1].component, 'son');
+
+    t.end();
+});