How to resolve excessive Azure Function App logs?

Question

Got a function app and had it working fine. I was running it with "func start" and the logs were reasonable and easy to read. Then I ran it one time and it started spouting a ridiculous amount of logs to which I found very little online. The logs appear as following:

MS_FUNCTION_LOGS 5,,,,,Host.LanguageWorkerConfig,"","Workers Directory set to: /usr/lib/node_modules/azure-functions-core-tools/bin/workers",3.0.14492.0,2020-10-26T15:56:35.7611803Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 5,,,,,Host.LanguageWorkerConfig,"","Found worker config: /usr/lib/node_modules/azure-functions-core-tools/bin/workers/node/worker.config.json",3.0.14492.0,2020-10-26T15:56:35.7637720Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 5,,,,,Host.LanguageWorkerConfig,"","EnvironmentVariable FUNCTIONS_WORKER_RUNTIME: python",3.0.14492.0,2020-10-26T15:56:35.7641060Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 4,,,,,Host.LanguageWorkerConfig,"","FUNCTIONS_WORKER_RUNTIME set to python. Skipping WorkerConfig for language:node",3.0.14492.0,2020-10-26T15:56:35.7642504Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 5,,,,,Host.LanguageWorkerConfig,"","Found worker config: /usr/lib/node_modules/azure-functions-core-tools/bin/workers/python/worker.config.json",3.0.14492.0,2020-10-26T15:56:35.7645808Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 5,,,,,Host.LanguageWorkerConfig,"","EnvironmentVariable FUNCTIONS_WORKER_RUNTIME: python",3.0.14492.0,2020-10-26T15:56:35.7648340Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 5,,,,,Host.LanguageWorkerConfig,"","EnvironmentVariable FUNCTIONS_WORKER_RUNTIME_VERSION: 3.7",3.0.14492.0,2020-10-26T15:56:35.7649523Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 5,,,,,Host.LanguageWorkerConfig,"","Added WorkerConfig for language: python",3.0.14492.0,2020-10-26T15:56:35.7650764Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 5,,,,,Host.LanguageWorkerConfig,"","Found worker config: /usr/lib/node_modules/azure-functions-core-tools/bin/workers/java/worker.config.json",3.0.14492.0,2020-10-26T15:56:35.7652113Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 5,,,,,Host.LanguageWorkerConfig,"","EnvironmentVariable FUNCTIONS_WORKER_RUNTIME: python",3.0.14492.0,2020-10-26T15:56:35.7654042Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 4,,,,,Host.LanguageWorkerConfig,"","FUNCTIONS_WORKER_RUNTIME set to python. Skipping WorkerConfig for language:java",3.0.14492.0,2020-10-26T15:56:35.7655065Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 5,,,,,Host.LanguageWorkerConfig,"","Found worker config: /usr/lib/node_modules/azure-functions-core-tools/bin/workers/powershell/worker.config.json",3.0.14492.0,2020-10-26T15:56:35.7656485Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 5,,,,,Host.LanguageWorkerConfig,"","EnvironmentVariable FUNCTIONS_WORKER_RUNTIME: python",3.0.14492.0,2020-10-26T15:56:35.7658274Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 4,,,,,Host.LanguageWorkerConfig,"","FUNCTIONS_WORKER_RUNTIME set to python. Skipping WorkerConfig for language:powershell",3.0.14492.0,2020-10-26T15:56:35.7659387Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 5,,,,,Host.LanguageWorkerConfig,"","Worker path for language worker python: /usr/lib/node_modules/azure-functions-core-tools/bin/workers/python",3.0.14492.0,2020-10-26T15:56:35.7661432Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 4,,,,,Host.Triggers.Warmup,"","Initializing Warmup Extension.",3.0.14492.0,2020-10-26T15:56:35.8127655Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 4,,,,Initializing,Host.Startup,"","Initializing Host. OperationId: '<operation_id>'.",3.0.14492.0,2020-10-26T15:56:35.8440157Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,
MS_FUNCTION_LOGS 4,,,,Initialization,Host.Startup,"","Host initialization: ConsecutiveErrors=0, StartupCount=1, OperationId=<operation_id>",3.0.14492.0,2020-10-26T15:56:35.8481365Z,,"",,<what_looks_like_a_key>,,<something_to_do_with_my_app>,,,,

As I don't know what the logs are, I've removed everything that looked like keys ( "<what_looks_like_a_key>" ) and removed all references to my function app ( "<something_to_do_with_my_app>" ).

Also, they resemble some form of CSVs, not sure how this is related though.

Does anyone know to stop my function app printing these logs? The command line tool has become pretty much unusable now due to these logs as they fill the terminal with junk that I don't want to see. Reinstalling azure-functions-core-tools didn't help.

(Related: https://stackoverflow.com/questions/57268026/how-to-remove-some-azure-functions-logs)

Answer 1

After discussing further with Microsoft technical support, we discovered together that the issue I was facing was related to the local.settings.json configuration.

I had a variable: CONTAINER_NAME that, after commenting out, resolved the issue.

It seems as if CONTAINER_NAME is a reserved variable name in Azure Functions.

Answer 2

@philmarius-new the source of this log is Host.LanguageWorkerConfig . So in the host.json file can you please add this "Host.LanguageWorkerConfig":"None" under the log level.
Please confirm if it helps.