{"id":611,"date":"2020-09-24T01:35:11","date_gmt":"2020-09-24T08:35:11","guid":{"rendered":"https:\/\/devblogs.microsoft.com\/azure-sdk\/?p=611"},"modified":"2020-09-24T17:00:02","modified_gmt":"2020-09-25T00:00:02","slug":"java-logging-azure-functions","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/azure-sdk\/java-logging-azure-functions\/","title":{"rendered":"Azure SDK for Java Logging in Azure Functions"},"content":{"rendered":"

In this post we will learn about Azure SDK for Java<\/a> application and HTTP logging scenarios in an Azure Functions environment. We will look at the scenario of managing secrets in the Azure Key Vault with the Key Vault and Identity client libraries and how to activate and access the SDK logs in the Azure Functions environment. The Azure SDK logs are helpful to analyze the underlying behavior of the SDKs and help to debug and root cause issues experienced in the deployed production environment of Azure Functions.<\/p>\n

What is Azure Functions?<\/h3>\n

Azure Functions<\/a> is a serverless computing service which allows developers to quickly deploy their code in the cloud and run the application at scale. It simplifies the application development and takes away the hassle of managing the infrastructure of the platform on which the code will be executed. The user can also configure a variety of triggers or events to execute their function, such as HTTP requests, scheduled runs, events, or notification hubs.<\/p>\n

Setting up Azure Functions Development Environment<\/h3>\n

VSCode and IntelliJ both offer great support to quickly get started with setting up your development environment to run Azure Functions. You can use the instructions below to setup the Azure Functions project in your preferred IDE.<\/p>\n

VSCode<\/h4>\n

Prequisites:<\/strong><\/p>\n

    \n
  1. Java Developer Kit<\/a>, version 8<\/li>\n
  2. Apache Maven<\/a> 3.0 or above<\/li>\n
  3. Visual Studio Code<\/a><\/li>\n
  4. Java Extension pack<\/a> for Visual Studio Code<\/li>\n
  5. Azure Functions Extension<\/a> for Visual Studio Code<\/li>\n<\/ol>\n

    Use the VSCode-quickstart<\/a> guide to setup your environment.<\/p>\n

    IntelliJ<\/h4>\n

    Prequisites:<\/strong><\/p>\n

      \n
    1. Java Developer Kit<\/a>, version 8<\/li>\n
    2. Apache Maven<\/a> 3.5.0 or above.<\/li>\n
    3. IntelliJ IDEA<\/a> Ultimate Edition or Community Edition<\/li>\n
    4. Function Core Tools<\/a><\/li>\n<\/ol>\n

      Use the IntelliJ-quickstart<\/a> guide to setup your environment.<\/p>\n

      Once you have setup the Azure Functions project in your preferred IDE, we will now begin adding the logic to connect to an Azure Key Vault using the azure-security-keyvault-secrets<\/a> and azure-identity<\/a> client libraries.<\/p>\n

      Maven Packages:<\/strong><\/p>\n

      Add the following Azure SDK client libraries to your Azure Functions pom file:<\/p>\n

      <dependency>\n    <groupId>com.azure<\/groupId>\n    <artifactId>azure-security-keyvault-secrets<\/artifactId>\n    <version>4.2.0<\/version>\n<\/dependency>\n\n<dependency>\n    <groupId>com.azure<\/groupId>\n    <artifactId>azure-identity<\/artifactId>\n    <version>1.1.0<\/version>\n<\/dependency> \n<\/code><\/pre>\n
      Latest packages for these client libraries can be found here:<\/p>\n
        \n
      1. azure-security-keyvault-secrets<\/a>.<\/li>\n
      2. azure-identity<\/a>.<\/li>\n<\/ol>\n
        Azure Functions Code Setup<\/h3>\n
        In the Function Setup below, we use the Azure Identity client library to connect to the Azure Key Vault and then create a secret in the Key Vault.<\/p>\n
        @FunctionName(\"AzureKeyVaultFunction\")\n    public HttpResponseMessage run(\n            @HttpTrigger(\n                name = \"req\",\n                methods = {HttpMethod.GET, HttpMethod.POST},\n                authLevel = AuthorizationLevel.ANONYMOUS)\n                HttpRequestMessage<Optional<String>> request,\n            final ExecutionContext context) {\n        \/\/ Parse query parameter\n        final String vaultUrl = request.getQueryParameters().get(\"vaultUrl\");\n\n        if (vaultUrl == null) {\n            return request.createResponseBuilder(HttpStatus.BAD_REQUEST).body(\"Please pass a vaultUrl on the query string or in the request body\").build();\n        }\n\n        SecretClient secretClient = new SecretClientBuilder()\n                .httpLogOptions(new HttpLogOptions().setLogLevel(HttpLogDetailLevel.BODY_AND_HEADERS))\n                .vaultUrl(vaultUrl)\n                .credential(new DefaultAzureCredentialBuilder().build())\n                .buildClient();\n\n        context.getLogger().info(\"Executing secret creation.\");\n        KeyVaultSecret secret = secretClient.setSecret(\"DummySecret\", \"DummyValue\");\n        context.getLogger().info(String.format(\"Successfully created secret with name: %s and value: %s\", secret.getName(), secret.getValue()));\n\n        return request.createResponseBuilder(HttpStatus.OK)\n                .build();\n    }\n\n<\/code><\/pre>\n
        We use DefaultAzureCredential<\/code> to authenticate SecretClient<\/code> with Azure Active Directory (AAD). In the production environment where the code is deployed to the Azure Function, ManagedIdentityCredential<\/code> will be used by the DefaultAzureCredential<\/code> to authenticate.<\/p>\n
        SecretClient secretClient = new SecretClientBuilder()\n        .vaultUrl(vaultUrl)\n        .credential(new DefaultAzureCredentialBuilder().build())\n        .buildClient();\n<\/code><\/pre>\n
        Creating a secret is as simple as this one line. Once executed, then we just print out the name and value of the created secret.<\/p>\n
          context.getLogger().info(\"Executing secret creation.\");\n  KeyVaultSecret secret = secretClient.setSecret(\"DummySecret\", \"DummyValue\");\n  context.getLogger().info(String.format(\"Successfully created secret with name: %s and value: %s\", secret.getName(), secret.getValue()));\n<\/code><\/pre>\n
        Configuring logging in Azure SDKs<\/h3>\n
        HTTP logging<\/strong><\/p>\n
        The HTTP logging will log all the HTTP requests being sent by the client. We will enable it in the above Azure Functions code via HttpLogOptions<\/code>.<\/p>\n
        We create and configure the http log options and then specify the options in the SecretClientBuilder<\/code>.<\/p>\n
        SecretClient secretClient = new SecretClientBuilder()\n        .httpLogOptions(new HttpLogOptions().setLogLevel(HttpLogDetailLevel.BODY_AND_HEADERS))\n        .vaultUrl(vaultUrl)\n        .credential(credential)\n        .buildClient();\n<\/code><\/pre>\n
        SDK logging<\/strong><\/p>\n
        Now, let\u2019s configure logging in the Azure client libraries being used in the code. The Azure SDK support logging via SLF4J<\/a>. This allows the applications to use their preferred logging framework with the Azure SDK. Detailed instructions to setup logging with Azure SDK can be found in the wiki<\/a>.<\/p>\n
        We will be using log4j logging framework in this blog via following steps: 1. Add the slf4j log4j dependency to the pom file<\/p>\n
        <dependency> \n    <groupId>org.slf4j<\/groupId>\n    <artifactId>slf4j-log4j12<\/artifactId>\n    <version>1.7.29<\/version>\n<\/dependency>\n<\/code><\/pre>\n
          \n
        1. Specify the log4j configuration in src\/main\/resources<\/code> via log4j.properties<\/code> file: We will be using a Rolling file appender to direct the output to a file instead of console and console output does not show up directly on Azure Functions console logs.<\/li>\n<\/ol>\n
          # Configure the root logger with appender file\nlog4j.rootLogger = DEBUG, FILE\n\n# Configure the file appender\nlog4j.appender.FILE=org.apache.log4j.DailyRollingFileAppender\n\n# Configure the name of the log file, it also contains the file system path of the Azure Functions environment to store the logs in this specific location. \nlog4j.appender.FILE.File=D:\/home\/LogFiles\/slf4j\/log.out\n\n# Configure the immediate flush to true (default)\nlog4j.appender.FILE.ImmediateFlush=true\n\n# Configure the threshold to debug mode\nlog4j.appender.FILE.Threshold=debug\n\n# Configure the append to true, should not overwrite\nlog4j.appender.FILE.Append=true\n\n# Configure the DatePattern\nlog4j.appender.FILE.DatePattern='.' yyyy-MM-dd-HH-mm\n\n# Configure the layout for file appender\nlog4j.appender.FILE.layout=org.apache.log4j.PatternLayout\nlog4j.appender.FILE.layout.conversionPattern=%m%n\n<\/pre>\n
          Deploy the Azure Function<\/h3>\n
            \n
          1. \n
            Let\u2019s now deploy the Azure Function and execute it in the cloud.<\/p>\n
            VSCode and IntelliJ both support deploying the Azure Functions to the cloud from the IDE itself. Follow the deployment instructions in their respective deployment guides below:<\/p>\n