Collectives™ on Stack Overflow
Find centralized, trusted content and collaborate around the technologies you use most.
Learn more about Collectives
Teams
Q&A for work
Connect and share knowledge within a single location that is structured and easy to search.
Learn more about Teams
In the following code, I use
%SCHEDULE%
to fetch Ncrontab string from environment variable in my azure function:
using System;
using System.IO;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
namespace Sample.AzureFunction
public class TimerExample
[FunctionName("TimerTrigger")]
public async Task TimerRun(
[TimerTrigger("%SCHEDULE%")] TimerInfo myTimer, ILogger log)
log.LogInformation("C# Timer trigger function processed a request.");
Then I build it as a docker image:
FROM mcr.microsoft.com/dotnet/sdk:6.0 AS installer-env
# Build requires 3.1 SDK
COPY --from=mcr.microsoft.com/dotnet/core/sdk:3.1 /usr/share/dotnet /usr/share/dotnet
COPY ./src /src/Sample.AzureFunction
RUN cd /src/Sample.AzureFunction && \
mkdir -p /home/site/wwwroot && \
dotnet publish *.csproj --output /home/site/wwwroot
# To enable ssh & remote debugging on app service change the base image to the one below
# FROM mcr.microsoft.com/azure-functions/dotnet:4-appservice
FROM mcr.microsoft.com/azure-functions/dotnet:4-slim
ENV AzureWebJobsScriptRoot=/home/site/wwwroot \
AzureFunctionsJobHost__Logging__Console__IsEnabled=true
COPY --from=installer-env ["/home/site/wwwroot", "/home/site/wwwroot"]
$ docker build --tag <dockerId>/sample.functionapp:develop .
When I run a cron job that repeats within 1 minute like this, that's fine:
$ docker run -p 8080:80 -it -e SCHEDULE='*/10 * * * * *' <dockerId>/sample.functionapp:develop
However, when I run a cron job that repeats in a longer timespan like this, errors occurred:
$ docker run -p 8080:80 -it -e SCHEDULE='0 */1 * * * *' <dockerId>/sample.functionapp:develop
The error says:
fail: Host.Startup[0]
The listener for function 'TimerTriggerFunc' was unable to start.
Microsoft.Azure.WebJobs.Host.Listeners.FunctionListenerException: The listener for function 'TimerTriggerFunc' was unable to start.
---> System.InvalidOperationException: Could not create BlobContainerClient for ScheduleMonitor
at Microsoft.Azure.WebJobs.Extensions.Timers.StorageScheduleMonitor.get_ContainerClient() in C:\azure-webjobs-sdk-extensions\src\WebJobs.Extensions.Timers.Storage\StorageScheduleMonitor.cs:line 83
at Microsoft.Azure.WebJobs.Extensions.Timers.StorageScheduleMonitor.GetStatusBlobClient(String timerName, Boolean createContainerIfNotExists) in C:\azure-webjobs-sdk-extensions\src\WebJobs.Extensions.Timers.Storage\StorageScheduleMonitor.cs:line 155
at Microsoft.Azure.WebJobs.Extensions.Timers.StorageScheduleMonitor.GetStatusAsync(String timerName) in C:\azure-webjobs-sdk-extensions\src\WebJobs.Extensions.Timers.Storage\StorageScheduleMonitor.cs:line 94
at Microsoft.Azure.WebJobs.Extensions.Timers.Listeners.TimerListener.StartAsync(CancellationToken cancellationToken) in C:\azure-webjobs-sdk-extensions\src\WebJobs.Extensions\Extensions\Timers\Listener\TimerListener.cs:line 105
at Microsoft.Azure.WebJobs.Host.Listeners.SingletonListener.StartAsync(CancellationToken cancellationToken) in C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Singleton\SingletonListener.cs:line 70
at Microsoft.Azure.WebJobs.Host.Listeners.FunctionListener.StartAsync(CancellationToken cancellationToken, Boolean allowRetry) in C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Listeners\FunctionListener.cs:line 68
--- End of inner exception stack trace ---
The full log is:
info: Host.Triggers.Warmup[0]
Initializing Warmup Extension.
info: Host.Startup[503]
Initializing Host. OperationId: '5492efd6-ae3f-455e-81f7-b3d51a78ec12'.
info: Host.Startup[504]
Host initialization: ConsecutiveErrors=0, StartupCount=1, OperationId=5492efd6-ae3f-455e-81f7-b3d51a78ec12
info: Microsoft.Azure.WebJobs.Hosting.OptionsLoggingService[0]
LoggerFilterOptions
"MinLevel": "None",
"Rules": [
"ProviderName": null,
"CategoryName": null,
"LogLevel": null,
"Filter": "<AddFilter>b__0"
"ProviderName": null,
"CategoryName": "Host.Function.ToolingConsoleLog",
"LogLevel": "Information",
"Filter": null
"ProviderName": "Microsoft.Azure.WebJobs.Script.WebHost.Diagnostics.SystemLoggerProvider",
"CategoryName": null,
"LogLevel": "None",
"Filter": null
"ProviderName": "Microsoft.Azure.WebJobs.Script.WebHost.Diagnostics.SystemLoggerProvider",
"CategoryName": null,
"LogLevel": null,
"Filter": "<AddFilter>b__0"
info: Microsoft.Azure.WebJobs.Hosting.OptionsLoggingService[0]
ConcurrencyOptions
"DynamicConcurrencyEnabled": false,
"MaximumFunctionConcurrency": 500,
"CPUThreshold": 0.8,
"SnapshotPersistenceEnabled": true
info: Microsoft.Azure.WebJobs.Hosting.OptionsLoggingService[0]
FunctionResultAggregatorOptions
"BatchSize": 1000,
"FlushTimeout": "00:00:30",
"IsEnabled": true
info: Microsoft.Azure.WebJobs.Hosting.OptionsLoggingService[0]
SingletonOptions
"LockPeriod": "00:00:15",
"ListenerLockPeriod": "00:01:00",
"LockAcquisitionTimeout": "10675199.02:48:05.4775807",
"LockAcquisitionPollingInterval": "00:00:05",
"ListenerLockRecoveryPollingInterval": "00:01:00"
info: Microsoft.Azure.WebJobs.Hosting.JobHostService[0]
Starting JobHost
info: Host.Startup[401]
Starting Host (HostId=dee9d0eebc87-2137340777, InstanceId=a0f6679e-ac77-411b-9793-9b8553973900, Version=4.13.0.0, ProcessId=1, AppDomainId=1, InDebugMode=False, InDiagnosticMode=False, FunctionsExtensionVersion=(null))
info: Host.Startup[314]
Loading functions metadata
info: Host.Startup[326]
Reading functions metadata
info: Host.Startup[327]
1 functions found
info: Host.Startup[315]
2 functions loaded
info: Host.Startup[0]
Generating 2 job function(s)
info: Host.Startup[0]
Found the following functions:
Sample.AzureFunction.HttpExample.Run
Sample.AzureFunction.TimerExample.Run
info: Microsoft.Azure.WebJobs.Script.WebHost.WebScriptHostHttpRoutesManager[0]
Initializing function HTTP routes
Mapped function route 'api/HttpExample' [get,post] to 'HttpExample'
info: Microsoft.Azure.WebJobs.Hosting.OptionsLoggingService[0]
HttpOptions
"DynamicThrottlesEnabled": false,
"EnableChunkedRequestBinding": false,
"MaxConcurrentRequests": -1,
"MaxOutstandingRequests": -1,
"RoutePrefix": "api"
info: Host.Startup[412]
Host initialized (142ms)
fail: Host.Startup[0]
The listener for function 'TimerTriggerFunc' was unable to start.
Microsoft.Azure.WebJobs.Host.Listeners.FunctionListenerException: The listener for function 'TimerTriggerFunc' was unable to start.
---> System.InvalidOperationException: Could not create BlobContainerClient for ScheduleMonitor
at Microsoft.Azure.WebJobs.Extensions.Timers.StorageScheduleMonitor.get_ContainerClient() in C:\azure-webjobs-sdk-extensions\src\WebJobs.Extensions.Timers.Storage\StorageScheduleMonitor.cs:line 83
at Microsoft.Azure.WebJobs.Extensions.Timers.StorageScheduleMonitor.GetStatusBlobClient(String timerName, Boolean createContainerIfNotExists) in C:\azure-webjobs-sdk-extensions\src\WebJobs.Extensions.Timers.Storage\StorageScheduleMonitor.cs:line 155
at Microsoft.Azure.WebJobs.Extensions.Timers.StorageScheduleMonitor.GetStatusAsync(String timerName) in C:\azure-webjobs-sdk-extensions\src\WebJobs.Extensions.Timers.Storage\StorageScheduleMonitor.cs:line 94
at Microsoft.Azure.WebJobs.Extensions.Timers.Listeners.TimerListener.StartAsync(CancellationToken cancellationToken) in C:\azure-webjobs-sdk-extensions\src\WebJobs.Extensions\Extensions\Timers\Listener\TimerListener.cs:line 105
at Microsoft.Azure.WebJobs.Host.Listeners.SingletonListener.StartAsync(CancellationToken cancellationToken) in C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Singleton\SingletonListener.cs:line 70
at Microsoft.Azure.WebJobs.Host.Listeners.FunctionListener.StartAsync(CancellationToken cancellationToken, Boolean allowRetry) in C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Listeners\FunctionListener.cs:line 68
--- End of inner exception stack trace ---
info: Host.Startup[413]
Host started (175ms)
info: Host.Startup[0]
Job host started
Hosting environment: Production
Content root path: /azure-functions-host
Now listening on: http://[::]:80
Application started. Press Ctrl+C to shut down.
info: Host.Startup[0]
Retrying to start listener for function 'TimerTriggerFunc' (Attempt 1)
info: Host.Startup[0]
Listener successfully started for function 'TimerTriggerFunc' after 1 retries.
info: Host.General[337]
Host lock lease acquired by instance ID '000000000000000000000000C2D27438'.
Hope anyone can help, thank in advance!
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.