Azure Webjob Incompatibility with NewtonSoft - json.net

Question

I'm getting the following exception when my Azure WebJob handler starts up:
System.IO.FileLoadException was unhandled FileName=Newtonsoft.Json,
Version=6.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed
FusionLog==== Pre-bind state information === LOG: DisplayName =
Newtonsoft.Json, Version=6.0.0.0, Culture=neutral,
PublicKeyToken=30ad4fe6b2a6aeed (Fully-specified) LOG: Appbase =
file:///C:/Programming/ConnellCampaigns/src/UploadProcessor/bin/Debug/net46/win7-x64/
LOG: Initial PrivatePath = NULL Calling assembly :
Microsoft.Azure.WebJobs.Host, Version=1.1.2.0, Culture=neutral,
PublicKeyToken=31bf3856ad364e35.
=== LOG: This bind starts in default load context. LOG: Using application configuration file:
C:\Programming\ConnellCampaigns\src\UploadProcessor\bin\Debug\net46\win7-x64\UploadProcessor.exe.Config
LOG: Using host configuration file: LOG: Using machine configuration
file from
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\config\machine.config.
LOG: Redirect found in application configuration file: 6.0.0.0
redirected to 6.0.0.0. LOG: Post-policy reference: Newtonsoft.Json,
Version=6.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed LOG:
Attempting download of new URL
file:///C:/Programming/ConnellCampaigns/src/UploadProcessor/bin/Debug/net46/win7-x64/Newtonsoft.Json.DLL.
WRN: Comparing the assembly name resulted in the mismatch: Major
Version ERR: Failed to complete setup of assembly (hr = 0x80131040).
Probing terminated.
HResult=-2146234304 Message=Could not load file or assembly
'Newtonsoft.Json, Version=6.0.0.0, Culture=neutral,
PublicKeyToken=30ad4fe6b2a6aeed' or one of its dependencies. The
located assembly's manifest definition does not match the assembly
reference. (Exception from HRESULT: 0x80131040)
Source=Microsoft.Azure.WebJobs.Host StackTrace:
at Microsoft.Azure.WebJobs.Host.Protocols.PersistentQueueWriter1.<EnqueueAsync>d__0.MoveNext()
at System.Runtime.CompilerServices.AsyncTaskMethodBuilder1.Start[TStateMachine](TStateMachine&
stateMachine)
at Microsoft.Azure.WebJobs.Host.Protocols.PersistentQueueWriter`1.EnqueueAsync(T
message, CancellationToken cancellationToken)
at Microsoft.Azure.WebJobs.Host.Loggers.PersistentQueueLogger.LogHostStartedAsync(HostStartedMessage
message, CancellationToken cancellationToken)
at Microsoft.Azure.WebJobs.Host.Executors.JobHostContextFactory.LogHostStartedAsync(IFunctionIndex
functionIndex, HostOutputMessage hostOutputMessage,
IHostInstanceLogger logger, CancellationToken cancellationToken)
at Microsoft.Azure.WebJobs.Host.Executors.JobHostContextFactory.d__b.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task
task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task
task)
at Microsoft.Azure.WebJobs.Host.Executors.JobHostContextFactory.d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task
task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task
task)
at Microsoft.Azure.WebJobs.JobHost.d__f.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task
task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task
task)
at Microsoft.Azure.WebJobs.JobHost.d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task
task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task
task)
at Microsoft.Azure.WebJobs.JobHost.Start()
at Microsoft.Azure.WebJobs.JobHost.RunAndBlock()
at UploadProcessor.Program.Main(String[] args) in C:\Programming\ConnellCampaigns\src\UploadProcessor\Program.cs:line 25
InnerException:
This only happens if I specify the latest version - 9.0.1 - of NewtonSoft's JSON assembly in project.json.
I can make the error go away by specifying the last v6 issue of the library (6.0.8). But that introduces dependency warnings.
I don't understand why Microsoft.Azure.WebJobs.Host insists on an older version of the library. Its nuget page says it's compatible with any version >= 6.0.8.
How do I resolve this?

Answer 1

The exception trace you posted above says you have a binding redirect in your application config file:
Redirect found in application configuration file: 6.0.0.0 redirected to 6.0.0.0.
Try changing it to redirect to the assembly version you're actually using:
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<dependentAssembly>
<assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-9.0.0.0" newVersion="9.0.0.0" />
</dependentAssembly>
</assemblyBinding>
Important note: binding redirects use the Assembly Version, not the File Version. So for Json.Net 9.0.x, this would be 9.0.0.0. If you try to use the File Version as the newVersion of the redirect, the redirect will not work because it won't match the Assembly Version of the actual assembly.