How to configure file target in nlog.config

General
, ,
1

Hi,

I’m trying to containerize a windows application that uses Nlog for logging. The app writes to file targets. Here is part of the nlog.config for the application. Please note the fileName parameter. That resolves to C:\Users\Public\Documents\xxxxxxxx\xxxxxxxx\Logs on the local hard drive.

What I want to know is how to specify the file path for a containerized application in my nlog.config. I have a docker compose yml file that defines volumes. I have a decent understanding of how volumes work. But, I don’t know what to put in my nlog.config for the fileName parameter. I would like to write to the app_data volume.

<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <extensions>
    <add assembly="DotnetUtils"/>
  </extensions>
  <targets async="true">
    <target name="con" xsi:type="Console"
        layout="${level} - ${message}${onexception:inner=${newline}${literal:text=  Exception\: }${exception:format=Message})}" />
    <target name="file" xsi:type="File" encoding="utf-8"
        fileName="${specialfolder:folder=CommonDocuments:file=xxxxxxxx/xxxxxxxx/Logs/xxxxxxxx.log}"
        archiveFileName="${specialfolder:folder=CommonDocuments:file=xxxxxxxx/xxxxxxxx /Logs/xxxxxxxxr}.{#}.log"
        layout="${longdate:universalTime=True} ${level} ${threadid} ${message} ${onexception:${newline}${exception:format=Message,StackTrace:maxInnerExceptionLevel=4:innerFormat=Message,StackTrace}}"
        createDirs="true" deleteOldFileOnStartup="false"
        archiveEvery="Day" maxArchiveFiles="9" archiveAboveSize="67108864" archiveNumbering="Rolling"
        concurrentWrites="false" enableFileDelete="true" keepFileOpen="false" autoFlush="true" />

services:
  web_api:
    container_name: xxxxxxxx_api_app
    build: .
    ports:
      - 8080:8080
    volumes:
      - app_data:/var/logs
    depends_on:
      - "db"
  db:
    image: postgres
    container_name: postgres_db
    ports:
      - 5432:5432
    environment:
      POSTGRES_PASSWORD: xxxxxxxx
      POSTGRES_HOST: db
    volumes:
      - postgres_data:/var/lib/postgresql/data

volumes:
  postgres_data:
  app_data:
2

The mount point which is on the left side of the colon in the volume mapping definition. But I don’t think Windows containers would have /var/logs that is a Linux path and you already shared the path would be

C:\Users\Public\Documents\xxxxxxxx\xxxxxxxx\Logs

so that is what you need to configure in anything that runs in the container and that is where you need to mount the volume.

3

Well that turned out to be easy but took some time to figure out. Screen print:

services:
  web_api:
    container_name: persons_api_app
    build: .
    ports:
      - 8080:8080
    volumes:
      - app_data_nlog_internal:/var/nlog/internal
      - app_data_nlog_application:/var/nlog/application
    depends_on:
      - "db"
  db:
    image: postgres
    container_name: postgres_db
    ports:
      - 5432:5432
    environment:
      POSTGRES_PASSWORD: xxxxxxxx
      POSTGRES_HOST: db
    volumes:
      - postgres_data:/var/lib/postgresql/data

volumes:
  postgres_data:
  app_data_nlog_internal:
  app_data_nlog_application:

<?xml version="1.0" encoding="utf-8"?>
<nlog
  xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  autoReload="true"
  internalLogLevel="Trace"
  internalLogFile="/var/nlog/internal/internallog.log"
  throwConfigExceptions="true">
  <targets>
    <target
      xsi:type="File"
      name="logfile"
      fileName="/var/nlog/application/nlog-${date:format=yyyy-MM-dd}.log"
      archiveFileName="/var/nlog/application/nlog-{date:format=yyyy-MM-dd}.{#}.log"
      layout="${longdate:universalTime=True} ${level} ${threadid} ${message} ${onexception:${newline}${exception:format=Message,StackTrace:maxInnerExceptionLevel=4:innerFormat=Message,StackTrace}}"
      createDirs="true"
      deleteOldFileOnStartup="false"
      archiveEvery="Day"
      maxArchiveFiles="9"
      archiveAboveSize="67108864"
      archiveNumbering="Rolling"
      concurrentWrites="false"
      enableFileDelete="true"
      keepFileOpen="false"
      autoFlush="true" />
    <target
      xsi:type="Console"
      name="logconsole" />
  </targets>
  <rules>
    <logger name="*" minlevel="Trace" writeTo="logconsole,logfile" />
  </rules>
</nlog>

image
image688×807 36.6 KB

4

Well, since you started the topic with

I assumed Windows containers as Windows applications would not run in a Linux container, but it looks like yoou are using Linux containers

5

Yeah, the Postgres image is most likely based on a Linux image.

I also have a task to create a windows container but then run the Postgres windows installer within the container. That will be interesting too and probably a little bit easier for me.