feat(mojaloop/#2928): add contextual logging functionality

README.md

@@ -15,7 +15,7 @@ Edit the file in `./config/default.json` to configure the logger, or set the fol
 | --- | --- | --- | --- |
 | `LOG_LEVEL` | Also `CSL_LOG_LEVEL` | `info` | `error`, `warn`, `audit`, `trace`, `info`, `perf`, `verbose`, `debug`, `silly` |
 | `CSL_LOG_LEVEL` | Sets the log level | `info` | `error`, `warn`, `audit`, `trace`, `info`, `perf`, `verbose`, `debug`, `silly` |
-| `LOG_FILTER` | Also `CSL_LOG_FILTER` | `""` | e.g. `"error, trace, verbose" | 
+| `LOG_FILTER` | Also `CSL_LOG_FILTER` | `""` | e.g. `"error, trace, verbose" |
 | `CSL_LOG_FILTER` | Applies a log filter. Specify a comma separated list of individual log levels to be included instead of specifying a `LOG_LEVEL` | `""` | e.g. `"error, trace, verbose" |
 | `CSL_LOG_TRANSPORT` | Selects the transport method. Either `console` or `file`. Uses the same transport for errors and standard logs | `console` | `console`, `file`
 | `CSL_TRANSPORT_FILE_OPTIONS` | _Optional._ Required if `LOG_TRANSPORT=file`. Configures the winston file transport | See `default.json` | See the [Winston Docs](https://github.com/winstonjs/winston#common-transport-options) |
@@ -70,6 +70,17 @@ npm run audit:check
 
 And commit the changed `audit-resolve.json` to ensure that CircleCI will build correctly.
 
+## Contextual Logging
+
+If you need contextual logging, an context object can be passed using Logger.child({'context': {a:1}}).info("Message").
+
+```bash
+Output: timestamp - info: {
+  a: 1,
+  message: 'Message'
+}
+```
+
 ## Automated Releases
 
 As part of our CI/CD process, we use a combination of CircleCI, standard-version