azure-functions

# Azure Functions Skill This skill provides expert guidance for Azure Functions. Covers troubleshooting, best practices, decision making, limits & quotas, security, configuration, integrations & coding patterns, and deployment. It combines local quick-reference content with remote documentation fetching capabilities. ## How to Use This Skill > **IMPORTANT for Agent**: Use the **Category Index** below to locate relevant sections. For categories with line ranges (e.g., `L35-L120`), use `read_file` with the specified lines. For categories with file links (e.g., `[security.md](security.md)`), use `read_file` on the linked reference file > **IMPORTANT for Agent**: If `metadata.generated_at` is more than 3 months old, suggest the user pull the latest version from the repository. If `mcp_microsoftdocs` tools are not available, suggest the user install it: [Installation Guide](https://github.com/MicrosoftDocs/mcp/blob/main/README.md) This skill requires **network access** to fetch documentation content: - **Preferred**: Use `mcp_microsoftdocs:microsoft_docs_fetch` with query string `from=learn-agent-skill`. Returns Markdown. - **Fallback**: Use `fetch_webpage` with query string `from=learn-agent-skill&accept=text/markdown`. Returns Markdown. ## Category Index | Category | Lines | Description | |----------|-------|-------------| | Troubleshooting | L36-L72 | Diagnosing and fixing Azure Functions errors (AZFD/AZFW codes), storage and config issues, runtime/SDK/version problems, networking, and language-specific (Node.js/Python) failures. | | Best Practices | L73-L89 | Guidance on performance, reliability, HttpClient usage, DI, idempotency, event processing, and language-specific (Node.js, .NET, Python) optimization best practices for Azure Functions | | Decision Making | L90-L114 | Guidance on choosing Functions hosting/runtime options, cost and networking tradeoffs, and planning/migrating between plans, runtimes, and platforms (incl. AWS Lambda and Cosmos/Service Bus upgrades). | | Limits & Quotas | L115-L122 | Scaling limits, concurrency settings, target-based trigger scaling, and language/runtime support lifecycles for Azure Functions. | | Security | L123-L135 | Guides for securing Functions: encryption at rest, secure storage and keys, private access (VNet/private endpoints), managed identity for SQL, and App Service security features. | | Configuration | L136-L181 | Configuring Azure Functions runtime, bindings, triggers, networking, monitoring, app settings, hosted skills, and language/runtime versions, including local development and OpenTelemetry setup. | | Integrations & Coding Patterns | L182-L284 | Patterns and how-tos for wiring Functions to external systems (HTTP, storage, messaging, databases, AI/OpenAI, Dapr, MCP, SignalR/Web PubSub) via triggers, input/output bindings, and worker extensions. | | Deployment | L285-L312 | Deploying Azure Functions: provisioning hosting (Bicep/ARM/Terraform/PowerShell), CI/CD (GitHub Actions, Azure Pipelines), slots, containers/Kubernetes, language‑specific builds, and rollback/migration. | ### Troubleshooting | Topic | URL | |-------|-----| | Resolve AZFD0001 missing AzureWebJobsStorage setting | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0001 | | Fix AZFD0002 invalid AzureWebJobsStorage value | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0002 | | Troubleshoot AZFD0003 StorageException fetching diagnostics | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0003 | | Resolve AZFD0004 Azure Functions host ID collision | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0004 | | Fix AZFD0005 external startup exception in Functions | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0005 | | Resolve AZFD0006 SAS token expiring in Functions | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0006 | | Resolve AZFD0007 too many secrets backups | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0007 | | Fix AZFD0008 archive-tier Blob secrets repository | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0008 | | Resolve AZFD0009 unable to parse host.json | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0009 | | Fix AZFD0010 TZ/WEBSITE_TIME_ZONE on Linux Consumption | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0010 | | Resolve AZFD0011 missing FUNCTIONS_WORKER_RUNTIME | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0011 | | Fix AZFD0013 mismatched FUNCTIONS_WORKER_RUNTIME and payload | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0013 | | Resolve AZFD0015 non-CRON timer trigger schedule | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0015 | | Fix AZFW0100 error running Functions Core Tools | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/msbuild-sdk-rules/azfw0100 | | Resolve AZFW0101 conflicting extension packages error | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/msbuild-sdk-rules/azfw0101 | | Fix AZFW0102 duplicate extension packages in Functions | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/msbuild-sdk-rules/azfw0102 | | Resolve AZFW0103 invalid extension package version | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/msbuild-sdk-rules/azfw0103 | | Handle AZFW0104 Functions version end-of-life error | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/msbuild-sdk-rules/azfw0104 | | Fix AZFW0105 incompatible Azure Functions SDK reference | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/msbuild-sdk-rules/azfw0105 | | Resolve AZFW0106 unknown Azure Functions version | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/msbuild-sdk-rules/azfw0106 | | Fix AZFW0107 unsupported target framework in Functions | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/msbuild-sdk-rules/azfw0107 | | Resolve AZFW0108 extension bundle not restored before build | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/msbuild-sdk-rules/azfw0108 | | Handle AZFW0109 generated project shouldn’t be built error | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/msbuild-sdk-rules/azfw0109 | | Resolve AZFW0110 FunctionsEnableWorkerIndexing deprecation | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/msbuild-sdk-rules/azfw0110 | | Fix AZFW0111 missing Azure Functions worker package | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/msbuild-sdk-rules/azfw0111 | | Fix AZFW0001 invalid binding attributes in Functions | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/net-worker-rules/azfw0001 | | Handle errors and retries in Azure Functions | https://learn.microsoft.com/en-us/azure/azure-functions/functions-bindings-error-pages | | Handle errors and retries in Azure Functions | https://learn.microsoft.com/en-us/azure/azure-functions/functions-bindings-error-pages | | Resolve common Azure Functions networking issues | https://learn.microsoft.com/en-us/azure/azure-functions/functions-networking-faq | | Troubleshoot Node.js Azure Functions runtime issues | https://learn.microsoft.com/en-us/azure/azure-functions/functions-node-troubleshoot | | Fix 'Azure Functions Runtime is unreachable' storage errors | https://learn.microsoft.com/en-us/azure/azure-functions/functions-recover-storage-account | | Diagnose and fix Python Azure Functions errors | https://learn.microsoft.com/en-us/azure/azure-functions/recover-python-functions | | Diagnose and fix Start/Stop VMs for Azure Functions | https://learn.microsoft.com/en-us/azure/azure-functions/start-stop-v2/troubleshoot | ### Best Practices | Topic | URL | |-------|-----| | Avoid async void in Azure Functions (AZF0001) | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/sdk-rules/azf0001 | | Optimize HttpClient usage in Functions (AZF0002) | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/sdk-rules/azf0002 | | Apply Azure Functions performance best practices | https://learn.microsoft.com/en-us/azure/azure-functions/functions-best-practices | | Implement dependency injection in .NET Azure Functions | https://learn.microsoft.com/en-us/azure/azure-functions/functions-dotnet-dependency-injection | | Design idempotent Azure Functions for duplicate events | https://learn.microsoft.com/en-us/azure/azure-functions/functions-idempotent | | Implement Node.js Azure Functions with v3/v4 models | https://learn.microsoft.com/en-us/azure/azure-functions/functions-reference-node | | Implement Azure Functions with Node.js programming model | https://learn.microsoft.com/en-us/azure/azure-functions/functions-reference-node | | Implement Azure Functions with Node.js programming model | https://learn.microsoft.com/en-us/azure/azure-functions/functions-reference-node | | Implement reliable event processing with Azure Functions | https://learn.microsoft.com/en-us/azure/azure-functions/functions-reliable-event-processing | | Optimize Node.js Azure Functions performance and scaling | https://learn.microsoft.com/en-us/azure/azure-functions/node-scale-performance | | Optimize Azure Functions performance and reliability | https://learn.microsoft.com/en-us/azure/azure-functions/performance-reliability | | Profile and reduce memory usage in Python Azure Functions | https://learn.microsoft.com/en-us/azure/azure-functions/python-memory-profiler-reference | | Optimize throughput and scaling for Python Azure Functions | https://learn.microsoft.com/en-us/azure/azure-functions/python-scale-performance-reference | ### Decision Making | Topic | URL | |-------|-----| | Plan migration from legacy Azure Functions Consumption plan | https://learn.microsoft.com/en-us/azure/azure-functions/consumption-plan | | Choose and use Azure Functions Dedicated hosting | https://learn.microsoft.com/en-us/azure/azure-functions/dedicated-plan | | Decide between in-process and isolated .NET Functions | https://learn.microsoft.com/en-us/azure/azure-functions/dotnet-isolated-in-process-differences | | Decide when to use Flex Consumption for Functions | https://learn.microsoft.com/en-us/azure/azure-functions/flex-consumption-plan | | Select Azure integration and automation platforms | https://learn.microsoft.com/en-us/azure/azure-functions/functions-compare-logic-apps-ms-flow-webjobs | | Estimate and compare Azure Functions consumption plan costs | https://learn.microsoft.com/en-us/azure/azure-functions/functions-consumption-costs | | Choose Azure Container Apps hosting for Functions | https://learn.microsoft.com/en-us/azure/azure-functions/functions-container-apps-hosting | | Choose AI integration options for Azure Functions | https://learn.microsoft.com/en-us/azure/azure-functions/functions-create-ai-enabled-apps | | Choose Azure Functions networking options | https://learn.microsoft.com/en-us/azure/azure-functions/functions-networking-options | | Choose Azure Functions scale and hosting plans | https://learn.microsoft.com/en-us/azure/azure-functions/functions-scale | | Choose Azure Functions hosting and scale options | https://learn.microsoft.com/en-us/azure/azure-functions/functions-scale | | Choose the right Azure Functions runtime version | https://learn.microsoft.com/en-us/azure/azure-functions/functions-versions | | Understand Azure Functions language support lifecycle | https://learn.microsoft.com/en-us/azure/azure-functions/language-support-policy | | Upgrade Azure Cosmos DB Functions extension from v3 to v4 | https://learn.microsoft.com/en-us/azure/azure-functions/migrate-cosmos-db-version-3-version-4 | | Migrate C# Azure Functions from in-process to isolated | https://learn.microsoft.com/en-us/azure/azure-functions/migrate-dotnet-to-isolated-model | | Migrate Azure Functions Service Bus extension to v5 | https://learn.microsoft.com/en-us/azure/azure-functions/migrate-service-bus-version-4-version-5 | | Upgrade Azure Functions v1 apps to v4 runtime | https://learn.microsoft.com/en-us/azure/azure-functions/migrate-version-1-version-4 | | Plan migration from Azure Functions v3 to v4 runtime | https://learn.microsoft.com/en-us/azure/azure-functions/migrate-version-3-version-4 | | Decide and plan migration from AWS Lambda to Azure Functions | https://learn.microsoft.com/en-us/azure/azure-functions/migration/migrate-aws-lambda-to-azure-functions | | Migrate Linux Consumption Functions to Flex Consumption | https://learn.microsoft.com/en-us/azure/azure-functions/migration/scenario-migrate-linux-consumption-to-flex | | Plan Azure Functions storage usage by hosting plan | https://learn.microsoft.com/en-us/azure/azure-functions/storage-considerations | ### Limits & Quotas | Topic | URL | |-------|-----| | Understand event-driven scaling limits in Azure Functions | https://learn.microsoft.com/en-us/azure/azure-functions/event-driven-scaling | | Configure concurrency behavior in Azure Functions | https://learn.microsoft.com/en-us/azure/azure-functions/functions-concurrency | | Use target-based scaling for Azure Functions triggers | https://learn.microsoft.com/en-us/azure/azure-functions/functions-target-based-scaling | | Check Azure Functions language support lifecycle | https://learn.microsoft.com/en-us/azure/azure-functions/supported-languages | ### Security | Topic | URL | |-------|-----| | Encrypt Azure Functions application source at rest | https://learn.microsoft.com/en-us/azure/azure-functions/configure-encrypt-at-rest-using-cmk | | Use secured storage accounts with Azure Functions | https://learn.microsoft.com/en-us/azure/azure-functions/configure-networking-how-to | | Handle AZFD0012 non-highly identifiable secret warnings | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0012 | | Manage Azure Functions access keys securely | https://learn.microsoft.com/en-us/azure/azure-functions/function-keys-how-to | | Restrict Azure Functions access using private site access | https://learn.microsoft.com/en-us/azure/azure-functions/functions-create-private-site-access | | Secure Azure Functions with VNet private endpoints | https://learn.microsoft.com/en-us/azure/azure-functions/functions-create-vnet | | Secure Azure Functions SQL access with managed identity | https://learn.microsoft.com/en-us/azure/azure-functions/functions-identity-access-azure-sql-with-managed-identity | | Securely host MCP servers on Azure Functions | https://learn.microsoft.com/en-us/azure/azure-functions/functions-mcp-tutorial | | Secure Azure Functions with App Service features | https://learn.microsoft.com/en-us/azure/azure-functions/security-concepts | ### Configuration | Topic | URL | |-------|-----|