Error loading hostpolicy.dll while deploying .NET Core console app to Azure WebJobs

Question

I have followed this tutorial to deploy a .NET Core console application to an Azure Web Service WebJob.

My app is running locally without any issue (with dotnet 1.0.0-preview2-003131) but when I try to run it from Azure console I have the following error :

Failed to load the dll from [D:\local\VirtualDirectory0\site\wwwroot\app_data\jobs\triggered\PopcornExportWebJob\hostpolicy.dll], HRESULT: 0x800700C1**

An error occurred while loading required library hostpolicy.dll from [D:\local\VirtualDirectory0\site\wwwroot\app_data\jobs\triggered\PopcornExportWebJob]

The version of Azure .Net is 1.0.0-rc4-004771 and the hostpolicy.dll file is the same than I use locally. In fact, when I download the zip of my deploy from Azure and when I run it locally, it is working fine. But it fails on Azure environment.

Also, here is my project.json:

{
      "publishOptions": {
        "include": [
          "run.cmd"
        ]
      },
      "buildOptions": {
        "emitEntryPoint": true,
        "copyToOutput": "appsettings.json"
      },
      "copyright": "bbougot",
      "dependencies": {
        "FubarCoder.RestSharp.Portable.Core": "4.0.7",
        "FubarCoder.RestSharp.Portable.HttpClient": "4.0.7",
        "Microsoft.ApplicationInsights.AspNetCore": "2.0.0",
        "Microsoft.Extensions.Configuration": "1.1.0",
        "Microsoft.Extensions.Configuration.Json": "1.1.0",
        "Microsoft.Extensions.DependencyInjection": "1.1.0",
        "Microsoft.Extensions.Logging": "1.1.0",
        "Microsoft.Extensions.Logging.Console": "1.1.0",
        "Microsoft.NETCore.App": "1.1.0",
        "MongoDB.Driver": "2.4.2",
        "StructureMap.Microsoft.DependencyInjection": "1.3.0"
      },
      "description": "Popcorn Api Exporter",
      "frameworks": {
        "netcoreapp1.1": {
          "imports": [
            "portable-net45+win8"
          ]
        }
      },
      "runtimes": {
        "win10-x64": {}
      },
      "scripts": {
        "postpublish": [ "7za.exe a -tzip PopcornExport.zip .\\bin\\Release\\PublishOutput\\*", 
                         ".\\WAWSDeploy.exe .\\PopcornExport.zip .\\popcornexport.PublishSettings /t app_data\\jobs\\triggered\\PopcornExportWebJob /v /d" ]
      },
      "title": "PopcornExport",
      "version": "1.0.0-*"
    }

I had to add the node runtimes (win10-x64 otherwise the app can't run locally). But, the Azure Web Service is running on Windows Server 2012. May it be an issue?

What did I miss?

Similar question [The library hostpolicy.dll was not found](//stackoverflow.com/q/38085430) — Michael Freidgeim, Oct 29 '17 at 12:27

score 20 · Accepted Answer · 2017-02-22T21:05:06.023

20

Alright, I've figured it out.

If you want to deploy a dotnet core app to Azure Web Service, include the runtime "win7-x86" if you are running your app in 32-Bit platform mode.

For a Visual Studio 2015 solution, your project.json should include :

  "runtimes": {
    "win10-x64": {},
    "win7-x86": {} //IMPORTANT FOR AZURE DEPLOY
  },

Or if you have already migrated to Visual Studio 2017, your .csproj should include this in PropertyGroup:

<RuntimeIdentifiers>win10-x64;win7-x86</RuntimeIdentifiers>

Also, your publish profile should include the same thing:

<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup>
    <PublishProtocol>FileSystem</PublishProtocol>
    <Configuration>Release</Configuration>
    <TargetFramework>netcoreapp1.1</TargetFramework>
    <PublishDir>bin\Release\PublishOutput</PublishDir>
    <RuntimeIdentifier>win7-x86</RuntimeIdentifier> // IMPORTANT
  </PropertyGroup>
</Project>

edited Feb 22 '17 at 21:05

answered Feb 22 '17 at 20:59

Please help to mark it as an answer that will help more communities who have the similar issue. – Tom Sun - MSFT Feb 23 '17 at 02:34
1

Using VS2017, this solution worked - BUT I had to reverse the order of the runtime identifiers as it kept defaulting to the win10 config and when I changed it in the UI - until I changed the csproj to: `win7-x86;win10-x64` – Steve Land Jun 07 '17 at 11:34
This answer saved my bacon today... +1 Thank you! I find it odd that win10-x64 prevented proper communication with our DB. Why would windows 10 not be the officially supported Azure version? – Benj Sanders Aug 31 '17 at 20:28
Thank you so much, this saved my day! Other than @Steveland83 mentioned, the order of runtimeIdentifiers was not a problem for me. – phifi Sep 01 '17 at 16:15

score 11 · Answer 2 · answered May 28 '19 at 11:02

11

I stopped seeing this error when I changed the contents of run.cmd from

dotnet MyWorker.dll

to

MyWorker.exe

answered May 28 '19 at 11:02

x5657

1,172
2
13
26

1

This led me to my fix also, though it was in my web.config: From: `` To: `` – Frank Apr 22 '20 at 21:07

score 3 · Answer 3 · answered Jun 02 '20 at 22:40

This error could happen if the bitness of your application doesn't match the bitness of your App Service (e.g. publishing a 64-bit deployment to an App Service running in 32-bit mode).

To solve this I had to change the bitness to the correct setting in Azure:

To match the bitness of my publish profile in VS:

score 0 · Answer 4 · answered Aug 20 '21 at 07:07

All the other answers in this topic didn't help me. But then I noticed with dotnet --list-runtimes that I used a newer version of dotnet core on my pc (3.1.18) than was installed by default for the Azure App Service (3.1.16). Once I installed "ASP.NET Core 3.1 (x64) Runtime" with Version 3.1.18 as an Extension in the app service configuration, the problem went away.

Error loading hostpolicy.dll while deploying .NET Core console app to Azure WebJobs

4 Answers4

Linked