feat: child redact option (#1059)

docs/api.md

@@ -141,6 +141,7 @@ logger.info('Message 2')
 If the `mixin` feature is being used merely to add static metadata to each log message,
 then a [child logger ⇗](/docs/child-loggers.md) should be used instead.
 
+<a id="opt-redact"></a>
 #### `redact` (Array | Object):
 
 Default: `undefined`
@@ -639,7 +640,7 @@ the process crashes or exits.
 Noop function.
 
 <a id="child"></a>
-### `logger.child(bindings) => logger`
+### `logger.child(bindings, [options]) => logger`
 
 The `logger.child` method allows for the creation of stateful loggers,
 where key-value pairs can be pinned to a logger causing them to be output
@@ -698,6 +699,25 @@ child.info({test: 'will be overwritten'})
 * See [`serializers` option](#opt-serializers)
 * See [pino.stdSerializers](#pino-stdSerializers)
 
+#### `options` (Object)
+
+Options for child logger. These options will override the parent logger options.
+
+##### `options.redact` (Array | Object)
+
+Setting `options.redact` to an array or object will override the parent `redact` options. To remove `redact` options inherited from the parent logger set this value as an empty array (`[]`).
+
+```js
+const logger = require('pino')({ redact: ['hello'] })
+logger.info({ hello: 'world' })
+// {"level":30,"time":1625794363403,"pid":67930,"hostname":"x","hello":"[Redacted]"}
+const child = logger.child({ foo: 'bar' }, { redact: ['foo'] })
+logger.info({ hello: 'world' })
+// {"level":30,"time":1625794553558,"pid":67930,"hostname":"x","hello":"world", "foo": "[Redacted]" }
+```
+
+* See [`redact` option](#opt-redact)
+
 <a id="bindings"></a>
 ### `logger.bindings()`
 

lib/proto.js

@@ -21,7 +21,11 @@ const {
   serializersSym,
   formattersSym,
   useOnlyCustomLevelsSym,
-  needsMetadataGsym
+  needsMetadataGsym,
+  redactFmtSym,
+  stringifySym,
+  formatOptsSym,
+  stringifiersSym
 } = require('./symbols')
 const {
   getLevel,
@@ -35,11 +39,13 @@ const {
 const {
   asChindings,
   asJson,
-  buildFormatters
+  buildFormatters,
+  stringify
 } = require('./tools')
 const {
   version
 } = require('./meta')
+const redaction = require('./redaction')
 
 // note: use of class is satirical
 // https://github.com/pinojs/pino/pull/433#pullrequestreview-127703127
@@ -71,10 +77,13 @@ module.exports = function () {
 }
 
 const resetChildingsFormatter = bindings => bindings
-function child (bindings) {
+// TODO: formatters, serializers, customLevels should move to options
+// and depercation warning should emit
+function child (bindings, options) {
   if (!bindings) {
     throw Error('missing bindings for child Pino')
   }
+  options = options || {} // default options to empty object
   const serializers = this[serializersSym]
   const formatters = this[formattersSym]
   const instance = Object.create(this)
@@ -119,6 +128,17 @@ function child (bindings) {
     instance.levels = mappings(bindings.customLevels, instance[useOnlyCustomLevelsSym])
     genLsCache(instance)
   }
+
+  // redact must place before asChindings and only replace if exist
+  if ((typeof options.redact === 'object' && options.redact !== null) || Array.isArray(options.redact)) {
+    instance.redact = options.redact // replace redact directly
+    const stringifiers = redaction(instance.redact, stringify)
+    const formatOpts = { stringify: stringifiers[redactFmtSym] }
+    instance[stringifySym] = stringify
+    instance[stringifiersSym] = stringifiers
+    instance[formatOptsSym] = formatOpts
+  }
+
   instance[chindingsSym] = asChindings(instance, bindings)
   const childLevel = bindings.level || this.level
   instance[setLevelSym](childLevel)

test/redact.test.js

@@ -775,3 +775,42 @@ test('child bindings are redacted using wildcard and plain path keys', async ({
   equal(req.headers.cookie, '[Redacted]')
   equal(req.method, '[Redacted]')
 })
+
+test('child can customize redact', async ({ equal }) => {
+  const stream = sink()
+  const instance = pino({ redact: ['req.method', '*.headers.cookie'] }, stream)
+  instance.child({
+    req: {
+      method: 'GET',
+      url: '/',
+      headers: {
+        cookie: 'SESSID=298zf09hf012fh2; csrftoken=u32t4o3tb3gg43; _gat=1;'
+      }
+    }
+  }, {
+    redact: ['req.url']
+  }).info('message completed')
+  const { req } = await once(stream, 'data')
+  equal(req.headers.cookie, 'SESSID=298zf09hf012fh2; csrftoken=u32t4o3tb3gg43; _gat=1;')
+  equal(req.method, 'GET')
+  equal(req.url, '[Redacted]')
+})
+
+test('child can remove parent redact by array', async ({ equal }) => {
+  const stream = sink()
+  const instance = pino({ redact: ['req.method', '*.headers.cookie'] }, stream)
+  instance.child({
+    req: {
+      method: 'GET',
+      url: '/',
+      headers: {
+        cookie: 'SESSID=298zf09hf012fh2; csrftoken=u32t4o3tb3gg43; _gat=1;'
+      }
+    }
+  }, {
+    redact: []
+  }).info('message completed')
+  const { req } = await once(stream, 'data')
+  equal(req.headers.cookie, 'SESSID=298zf09hf012fh2; csrftoken=u32t4o3tb3gg43; _gat=1;')
+  equal(req.method, 'GET')
+})