Add support for enabling verbose logging using environment variable (#105)

Verbose rendering logging have been possible to enable only thru
configuration file and when running in remote rendering setup.
This adds support for enabling verbose logging using environment
variable for both plugin and service mode.

Author: marefr

README.md

@@ -67,6 +67,16 @@ Change the listening port of the gRPC server. Default is `0` and will automatica
 GF_RENDERER_PLUGIN_GRPC_PORT=50059
 ```
 
+**Verbose logging:**
+
+Instruct headless Chrome whether to capture and log verbose information when rendering an image. Default is `false` and will only capture and log error messages. When enabled, `true`, debug messages are captured and logged as well.
+
+For the verbose information to be included in the Grafana server log you have to adjust the rendering log level to `debug`, see [Troubleshoot image rendering](https://grafana.com/docs/grafana/latest/administration/image_rendering/#troubleshoot-image-rendering) for instructions.
+
+```bash
+GF_RENDERER_PLUGIN_VERBOSE_LOGGING=true
+```
+
 ## Remote Rendering Using Docker
 
 Instead of installing and running the image renderer as a plugin, you can run it as a remote image rendering service using Docker. Read more about [remote rendering using Docker](https://github.com/grafana/grafana-image-renderer/blob/master/docs/remote_rendering_using_docker.md).

docs/remote_rendering_using_docker.md

@@ -13,23 +13,23 @@ You can override certain settings by using environment variables.
 Change the listening host of the HTTP server. Default is unset and will use the local host.
 
 ```bash
-export HTTP_HOST=localhost
+HTTP_HOST=localhost
 ```
 
 **HTTP port:**
 
 Change the listening port of the HTTP server. Default is `8081`. Setting `0` will automatically assign a port not in use.
 
 ```bash
-export HTTP_PORT=0
+HTTP_PORT=0
 ```
 
 **Default timezone:**
 
 Instruct headless Chrome to use a default timezone when not provided by Grafana, .e.g. when rendering panel image of alert. See [ICU’s metaZones.txt](https://cs.chromium.org/chromium/src/third_party/icu/source/data/misc/metaZones.txt?rcl=faee8bc70570192d82d2978a71e2a615788597d1) for a list of supported timezone IDs. Fallbacks to `TZ` environment variable if not set.
 
 ```bash
-export BROWSER_TZ=Europe/Stockholm
+BROWSER_TZ=Europe/Stockholm
 ```
 
 **Ignore HTTPS errors:**
@@ -38,24 +38,33 @@ Instruct headless Chrome whether to ignore HTTPS errors during navigation. Per d
 Due to the security risk it's not recommended to ignore HTTPS errors.
 
 ```bash
-export IGNORE_HTTPS_ERRORS=true
+IGNORE_HTTPS_ERRORS=true
 ```
 
 **Enable Prometheus metrics:**
 
 You can enable [Prometheus](https://prometheus.io/) metrics endpoint `/metrics` using the environment variable `ENABLE_METRICS`. Node.js and render request duration metrics are included, see [output example](#prometheus-metrics-endpoint-output-example) for details.
 
 ```bash
-export ENABLE_METRICS=true
+ENABLE_METRICS=true
 ```
 
 **Log level:**
 
 Change the log level. Default is `info` and will include log messages with level `error`, `warning` and info.
 
+```bash
+LOG_LEVEL=debug
+```
+
+**Verbose logging:**
+
+Instruct headless Chrome whether to capture and log verbose information when rendering an image. Default is `false` and will only capture and log error messages. When enabled (`true`) debug messages are captured and logged as well.
+
+Note that you need to change log level to `debug`, see above, for the verbose information to be included in the logs.
 
 ```bash
-export LOG_LEVEL=info
+RENDERING_VERBOSE_LOGGING=true
 ```
 
 ## Configuration file

src/app.ts

@@ -84,6 +84,10 @@ function populatePluginConfigFromEnv(config: PluginConfig, env: NodeJS.ProcessEn
   if (env['GF_RENDERER_PLUGIN_CHROME_BIN']) {
     config.rendering.chromeBin = env['GF_RENDERER_PLUGIN_CHROME_BIN'];
   }
+
+  if (env['GF_RENDERER_PLUGIN_VERBOSE_LOGGING']) {
+    config.rendering.verboseLogging = env['GF_RENDERER_PLUGIN_VERBOSE_LOGGING'] === 'true';
+  }
 }
 
 function populateServiceConfigFromEnv(config: ServiceConfig, env: NodeJS.ProcessEnv) {
@@ -128,4 +132,8 @@ function populateServiceConfigFromEnv(config: ServiceConfig, env: NodeJS.Process
   if (env['RENDERING_CLUSTERING_MAX_CONCURRENCY']) {
     config.rendering.clustering.maxConcurrency = parseInt(env['RENDERING_CLUSTERING_MAX_CONCURRENCY'] as string, 10);
   }
+
+  if (env['RENDERING_VERBOSE_LOGGING']) {
+    config.rendering.verboseLogging = env['RENDERING_VERBOSE_LOGGING'] === 'true';
+  }
 }