Re: [PR] MINOR: docs(config providers): adds a description of configuration providers [kafka]

[via GitHub]

mimaison commented on code in PR #16650:
URL: https://github.com/apache/kafka/pull/16650#discussion_r1688158358


##########
docs/ops.html:
##########
@@ -1247,7 +1247,165 @@ <h4 class="anchor-heading"><a id="prodconfig" 
class="anchor-link"></a><a href="#
 
   Our client configuration varies a fair amount between different use cases.
 
-  <h3 class="anchor-heading"><a id="java" class="anchor-link"></a><a 
href="#java">6.6 Java Version</a></h3>
+  <h3 class="anchor-heading">
+    <a id="config_providers" class="anchor-link"></a>
+    <a href="#config_providers">6.6 Configuration Providers</a>
+  </h3>
+  
+  <p>
+    Use configuration providers to load configuration data from external 
sources. This might include sensitive information, such as passwords, API keys, 
or other credentials.
+  </p>
+  
+  <p>You have the following options:</p>
+  <ul>
+    <li>
+      Use a custom provider by creating a Java class implementing the

Review Comment:
   I think we can remove `Java`. You could also use Scala for example to 
implement a custom ConfigProvider



##########
docs/ops.html:
##########
@@ -1247,7 +1247,165 @@ <h4 class="anchor-heading"><a id="prodconfig" 
class="anchor-link"></a><a href="#
 
   Our client configuration varies a fair amount between different use cases.
 
-  <h3 class="anchor-heading"><a id="java" class="anchor-link"></a><a 
href="#java">6.6 Java Version</a></h3>
+  <h3 class="anchor-heading">
+    <a id="config_providers" class="anchor-link"></a>
+    <a href="#config_providers">6.6 Configuration Providers</a>
+  </h3>
+  
+  <p>
+    Use configuration providers to load configuration data from external 
sources. This might include sensitive information, such as passwords, API keys, 
or other credentials.
+  </p>
+  
+  <p>You have the following options:</p>
+  <ul>
+    <li>
+      Use a custom provider by creating a Java class implementing the
+      <a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/ConfigProvider.html"><code>ConfigProvider</code></a>
 interface and packaging it into a JAR file.
+    </li>
+    <li>Use a built-in provider:</li>
+    <ul>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/DirectoryConfigProvider.html"><code>DirectoryConfigProvider</code></a></li>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/EnvVarConfigProvider.html"><code>EnvVarConfigProvider</code></a></li>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/FileConfigProvider.html"><code>FileConfigProvider</code></a></li>
+    </ul>
+  </ul>
+  
+  <p>
+    To use a configuration provider, specify it in your configuration file 
using the <code>config.providers</code> property. 

Review Comment:
   We can remove `file` in this sentence. You can also build a configuration 
programmatically.



##########
docs/ops.html:
##########
@@ -1247,7 +1247,165 @@ <h4 class="anchor-heading"><a id="prodconfig" 
class="anchor-link"></a><a href="#
 
   Our client configuration varies a fair amount between different use cases.
 
-  <h3 class="anchor-heading"><a id="java" class="anchor-link"></a><a 
href="#java">6.6 Java Version</a></h3>
+  <h3 class="anchor-heading">
+    <a id="config_providers" class="anchor-link"></a>
+    <a href="#config_providers">6.6 Configuration Providers</a>
+  </h3>
+  
+  <p>
+    Use configuration providers to load configuration data from external 
sources. This might include sensitive information, such as passwords, API keys, 
or other credentials.
+  </p>
+  
+  <p>You have the following options:</p>
+  <ul>
+    <li>
+      Use a custom provider by creating a Java class implementing the
+      <a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/ConfigProvider.html"><code>ConfigProvider</code></a>
 interface and packaging it into a JAR file.
+    </li>
+    <li>Use a built-in provider:</li>
+    <ul>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/DirectoryConfigProvider.html"><code>DirectoryConfigProvider</code></a></li>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/EnvVarConfigProvider.html"><code>EnvVarConfigProvider</code></a></li>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/FileConfigProvider.html"><code>FileConfigProvider</code></a></li>
+    </ul>
+  </ul>
+  
+  <p>
+    To use a configuration provider, specify it in your configuration file 
using the <code>config.providers</code> property. 
+  </p>
+  <p>
+    Each provider can have its own set of parameters, which are passed in a 
specific format.
+  </p>
+  
+  <h4 class="anchor-heading">
+    <a id="common_provider_params" class="anchor-link"></a>
+    <a href="#common_provider_params">Common Parameters</a>
+  </h4>
+  
+  <p>All configuration providers share a common way of passing parameters.</p>
+  <p>
+    You specify a comma-separated list of aliases and the fully-specified 
class that implements the configuration provider:
+  </p>
+  <pre><code>config.providers=provider1,provider2
+config.providers.provider1.class=com.example.Provider1
+config.providers.provider2.class=com.example.Provider2</code></pre>
+  <p>
+    Pass additional parameters to each provider as 
<code>config.providers.&lt;provider_alias&gt;.&lt;parameter_key&gt;=&lt;parameter_value&gt;</code>:
+  </p>
+  <pre><code>config.providers.provider1.param1=value1
+config.providers.provider1.param2=value2</code></pre>
+  
+  <h4 class="anchor-heading">
+    <a id="config_provider" class="anchor-link"></a>
+    <a href="#config_provider">ConfigProvider</a>
+  </h4>
+  
+  <p>
+    The <code>ConfigProvider</code> is a base interface for all configuration 
providers. Custom implementations of this interface can retrieve configuration 
data from various sources. You can then package and deploy the implementation 
as a JAR file and reference the provider's class in your configuration.

Review Comment:
   I think `deploy` is not the right term here. You just need to add the JAR to 
the classpath.



##########
docs/ops.html:
##########
@@ -1247,7 +1247,165 @@ <h4 class="anchor-heading"><a id="prodconfig" 
class="anchor-link"></a><a href="#
 
   Our client configuration varies a fair amount between different use cases.
 
-  <h3 class="anchor-heading"><a id="java" class="anchor-link"></a><a 
href="#java">6.6 Java Version</a></h3>
+  <h3 class="anchor-heading">
+    <a id="config_providers" class="anchor-link"></a>
+    <a href="#config_providers">6.6 Configuration Providers</a>
+  </h3>
+  
+  <p>
+    Use configuration providers to load configuration data from external 
sources. This might include sensitive information, such as passwords, API keys, 
or other credentials.
+  </p>
+  
+  <p>You have the following options:</p>
+  <ul>
+    <li>
+      Use a custom provider by creating a Java class implementing the
+      <a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/ConfigProvider.html"><code>ConfigProvider</code></a>
 interface and packaging it into a JAR file.
+    </li>
+    <li>Use a built-in provider:</li>
+    <ul>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/DirectoryConfigProvider.html"><code>DirectoryConfigProvider</code></a></li>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/EnvVarConfigProvider.html"><code>EnvVarConfigProvider</code></a></li>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/FileConfigProvider.html"><code>FileConfigProvider</code></a></li>
+    </ul>
+  </ul>
+  
+  <p>
+    To use a configuration provider, specify it in your configuration file 
using the <code>config.providers</code> property. 
+  </p>
+  <p>
+    Each provider can have its own set of parameters, which are passed in a 
specific format.
+  </p>
+  
+  <h4 class="anchor-heading">
+    <a id="common_provider_params" class="anchor-link"></a>
+    <a href="#common_provider_params">Common Parameters</a>
+  </h4>
+  
+  <p>All configuration providers share a common way of passing parameters.</p>
+  <p>
+    You specify a comma-separated list of aliases and the fully-specified 
class that implements the configuration provider:
+  </p>
+  <pre><code>config.providers=provider1,provider2
+config.providers.provider1.class=com.example.Provider1
+config.providers.provider2.class=com.example.Provider2</code></pre>
+  <p>
+    Pass additional parameters to each provider as 
<code>config.providers.&lt;provider_alias&gt;.&lt;parameter_key&gt;=&lt;parameter_value&gt;</code>:

Review Comment:
   The syntax is not correct. It should be 
`config.providers.<alias>.param.<name>=<value>`.
   
   Some of the examples below are missing `.param.` too.



##########
docs/ops.html:
##########
@@ -1247,7 +1247,165 @@ <h4 class="anchor-heading"><a id="prodconfig" 
class="anchor-link"></a><a href="#
 
   Our client configuration varies a fair amount between different use cases.
 
-  <h3 class="anchor-heading"><a id="java" class="anchor-link"></a><a 
href="#java">6.6 Java Version</a></h3>
+  <h3 class="anchor-heading">
+    <a id="config_providers" class="anchor-link"></a>
+    <a href="#config_providers">6.6 Configuration Providers</a>
+  </h3>
+  
+  <p>
+    Use configuration providers to load configuration data from external 
sources. This might include sensitive information, such as passwords, API keys, 
or other credentials.
+  </p>
+  
+  <p>You have the following options:</p>
+  <ul>
+    <li>
+      Use a custom provider by creating a Java class implementing the
+      <a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/ConfigProvider.html"><code>ConfigProvider</code></a>
 interface and packaging it into a JAR file.
+    </li>
+    <li>Use a built-in provider:</li>
+    <ul>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/DirectoryConfigProvider.html"><code>DirectoryConfigProvider</code></a></li>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/EnvVarConfigProvider.html"><code>EnvVarConfigProvider</code></a></li>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/FileConfigProvider.html"><code>FileConfigProvider</code></a></li>
+    </ul>
+  </ul>
+  
+  <p>
+    To use a configuration provider, specify it in your configuration file 
using the <code>config.providers</code> property. 
+  </p>
+  <p>
+    Each provider can have its own set of parameters, which are passed in a 
specific format.

Review Comment:
   If we rename the section below, we could move this paragraph in there.



##########
docs/ops.html:
##########
@@ -1247,7 +1247,165 @@ <h4 class="anchor-heading"><a id="prodconfig" 
class="anchor-link"></a><a href="#
 
   Our client configuration varies a fair amount between different use cases.
 
-  <h3 class="anchor-heading"><a id="java" class="anchor-link"></a><a 
href="#java">6.6 Java Version</a></h3>
+  <h3 class="anchor-heading">
+    <a id="config_providers" class="anchor-link"></a>
+    <a href="#config_providers">6.6 Configuration Providers</a>
+  </h3>
+  
+  <p>
+    Use configuration providers to load configuration data from external 
sources. This might include sensitive information, such as passwords, API keys, 
or other credentials.
+  </p>
+  
+  <p>You have the following options:</p>
+  <ul>
+    <li>
+      Use a custom provider by creating a Java class implementing the
+      <a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/ConfigProvider.html"><code>ConfigProvider</code></a>
 interface and packaging it into a JAR file.
+    </li>
+    <li>Use a built-in provider:</li>
+    <ul>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/DirectoryConfigProvider.html"><code>DirectoryConfigProvider</code></a></li>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/EnvVarConfigProvider.html"><code>EnvVarConfigProvider</code></a></li>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/FileConfigProvider.html"><code>FileConfigProvider</code></a></li>
+    </ul>
+  </ul>
+  
+  <p>
+    To use a configuration provider, specify it in your configuration file 
using the <code>config.providers</code> property. 
+  </p>
+  <p>
+    Each provider can have its own set of parameters, which are passed in a 
specific format.
+  </p>
+  
+  <h4 class="anchor-heading">
+    <a id="common_provider_params" class="anchor-link"></a>
+    <a href="#common_provider_params">Common Parameters</a>
+  </h4>
+  
+  <p>All configuration providers share a common way of passing parameters.</p>
+  <p>
+    You specify a comma-separated list of aliases and the fully-specified 
class that implements the configuration provider:
+  </p>
+  <pre><code>config.providers=provider1,provider2
+config.providers.provider1.class=com.example.Provider1
+config.providers.provider2.class=com.example.Provider2</code></pre>
+  <p>
+    Pass additional parameters to each provider as 
<code>config.providers.&lt;provider_alias&gt;.&lt;parameter_key&gt;=&lt;parameter_value&gt;</code>:
+  </p>
+  <pre><code>config.providers.provider1.param1=value1
+config.providers.provider1.param2=value2</code></pre>
+  
+  <h4 class="anchor-heading">
+    <a id="config_provider" class="anchor-link"></a>
+    <a href="#config_provider">ConfigProvider</a>
+  </h4>
+  
+  <p>
+    The <code>ConfigProvider</code> is a base interface for all configuration 
providers. Custom implementations of this interface can retrieve configuration 
data from various sources. You can then package and deploy the implementation 
as a JAR file and reference the provider's class in your configuration.
+  </p>
+  
+  <p><b>Example custom provider configuration</b></p>
+  <pre><code>config.providers=customProvider
+config.providers.customProvider.class=com.example.customProvider
+config.providers.customProvider.param1=value1
+config.providers.customProvider.param2=value2</code></pre>
+  
+  <h4 class="anchor-heading">
+    <a id="directory_config_provider" class="anchor-link"></a>
+    <a href="#directory_config_provider">DirectoryConfigProvider</a>
+  </h4>
+  
+  <p>
+    The <code>DirectoryConfigProvider</code> retrieves configuration data from 
files stored in a specified directory.
+  </p>
+  <p>
+    Each file represents a key, and its content is the value. You specify the 
path to the directory where the configuration files are stored using the 
<code>dir</code> parameter. This provider is useful for loading multiple 
configuration files and for organizing configuration data into separate files.
+  </p>
+  
+  <p><b>Example <code>DirectoryConfigProvider</code> configuration</b></p>
+  <pre><code>config.providers=dirProvider
+config.providers.dirProvider.class=org.apache.kafka.common.config.provider.DirectoryConfigProvider
+config.providers.dirProvider.param.dir=/path/to/config/directory</code></pre>
+  
+  <h4 class="anchor-heading">
+    <a id="env_var_config_provider" class="anchor-link"></a>
+    <a href="#env_var_config_provider">EnvVarConfigProvider</a>
+  </h4>
+  
+  <p>The <code>EnvVarConfigProvider</code> retrieves configuration data from 
environment variables.</p>
+  <p>No specific parameters are required, as it reads directly from the 
specified environment variables.</p>
+  <p>
+    This provider is useful for configuring applications running in 
containers, for example, to load certificates or JAAS configuration from 
environment variables mapped from secrets.
+  </p>
+  
+  <p><b>Example <code>EnvVarConfigProvider</code> configuration</b></p>
+  <pre><code>config.providers=envVarProvider
+config.providers.envVarProvider.class=org.apache.kafka.common.config.provider.EnvVarConfigProvider</code></pre>
+  
+  <h4 class="anchor-heading">
+    <a id="file_config_provider" class="anchor-link"></a>
+    <a href="#file_config_provider">FileConfigProvider</a>
+  </h4>
+  
+  <p>The <code>FileConfigProvider</code> retrieves configuration data from a 
single properties file.</p>
+  <p>You specify the path to the properties file using the <code>file</code> 
parameter.</p>
+  <p>This provider is useful for loading configuration data from mounted 
files.</p>
+  
+  <p><b>Example <code>FileConfigProvider</code> configuration</b></p>
+  <pre><code>config.providers=fileProvider
+config.providers.fileProvider.class=org.apache.kafka.common.config.provider.FileConfigProvider
+config.providers.fileProvider.param.file=/path/to/config.properties</code></pre>
+  
+  <h4 class="anchor-heading">
+    <a id="ref_config_provider" class="anchor-link"></a>
+    <a href="#ref_config_provider">Referencing configuration providers</a>
+  </h4>
+  <p>
+    To reference a property value supplied by a configuration provider, use 
the correct placeholder syntax:
+  </p>
+  <dl>
+    <dt><b><code>DirectoryConfigProvider</code></b></dt>
+    <dd>
+      <p><code>${dirProvider:&lt;path_to_file&gt;:&lt;file_name&gt;}</code></p>
+    </dd>
+    <dt><code><b>EnvVarConfigProvider</code></b></dt>
+    <dd>
+      <p><code>${envVarProvider:&lt;enVar_name&gt;}</code></p>
+    </dd>
+    
+    <dt><b><code>FileConfigProvider</code></b></dt>
+    <dd>
+      
<p><code>${fileProvider:&lt;path_and_filename&gt;:&lt;property&gt;}</code></p>
+    </dd>
+  </dl>
+  <p>
+    Here’s an example that uses a file configuration provider with Kafka 
Connect to provide authentication credentials to a database for a connector.
+  </p>
+  <p>
+    First, create a <code>connector-credentials.properties</code> 
configuration file with the following credentials:
+  </p>
+  <p><b>Example configuration file</b></p>
+<pre><code>dbUsername=my-username
+dbPassword=my-password</code></pre>
+  <p><em>NOTE: Ensure the appropriate permissions are set for securely 
accessing the properties file.
+    For additional security, consider encrypting sensitive information using a 
secret and implementing decryption in your application at runtime.
+  </em></p>
+  <p>
+    Specify a <code>FileConfigProvider</code> in the Kafka Connect 
configuration:
+  </p>
+  
+  <p><b>Example Kafka Connect configuration with an 
<code>FileConfigProvider</code></b></p>
+  <pre><code>config.providers=fileProvider
+config.providers.fileProvider.class=org.apache.kafka.common.config.provider.FileConfigProvider
+config.providers.fileProvider.config.path=/path/to/connector-properties</code></pre>

Review Comment:
   This line is not correct and should be removed. You don't provide the path 
when defining the provider, you only provide it when using the provider to 
retrieve a value.



##########
docs/ops.html:
##########
@@ -1247,7 +1247,165 @@ <h4 class="anchor-heading"><a id="prodconfig" 
class="anchor-link"></a><a href="#
 
   Our client configuration varies a fair amount between different use cases.
 
-  <h3 class="anchor-heading"><a id="java" class="anchor-link"></a><a 
href="#java">6.6 Java Version</a></h3>
+  <h3 class="anchor-heading">
+    <a id="config_providers" class="anchor-link"></a>
+    <a href="#config_providers">6.6 Configuration Providers</a>
+  </h3>
+  
+  <p>
+    Use configuration providers to load configuration data from external 
sources. This might include sensitive information, such as passwords, API keys, 
or other credentials.
+  </p>
+  
+  <p>You have the following options:</p>
+  <ul>
+    <li>
+      Use a custom provider by creating a Java class implementing the
+      <a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/ConfigProvider.html"><code>ConfigProvider</code></a>
 interface and packaging it into a JAR file.
+    </li>
+    <li>Use a built-in provider:</li>
+    <ul>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/DirectoryConfigProvider.html"><code>DirectoryConfigProvider</code></a></li>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/EnvVarConfigProvider.html"><code>EnvVarConfigProvider</code></a></li>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/FileConfigProvider.html"><code>FileConfigProvider</code></a></li>
+    </ul>
+  </ul>
+  
+  <p>
+    To use a configuration provider, specify it in your configuration file 
using the <code>config.providers</code> property. 
+  </p>
+  <p>
+    Each provider can have its own set of parameters, which are passed in a 
specific format.
+  </p>
+  
+  <h4 class="anchor-heading">
+    <a id="common_provider_params" class="anchor-link"></a>
+    <a href="#common_provider_params">Common Parameters</a>
+  </h4>
+  
+  <p>All configuration providers share a common way of passing parameters.</p>
+  <p>
+    You specify a comma-separated list of aliases and the fully-specified 
class that implements the configuration provider:
+  </p>
+  <pre><code>config.providers=provider1,provider2
+config.providers.provider1.class=com.example.Provider1
+config.providers.provider2.class=com.example.Provider2</code></pre>
+  <p>
+    Pass additional parameters to each provider as 
<code>config.providers.&lt;provider_alias&gt;.&lt;parameter_key&gt;=&lt;parameter_value&gt;</code>:
+  </p>
+  <pre><code>config.providers.provider1.param1=value1
+config.providers.provider1.param2=value2</code></pre>
+  
+  <h4 class="anchor-heading">
+    <a id="config_provider" class="anchor-link"></a>
+    <a href="#config_provider">ConfigProvider</a>
+  </h4>
+  
+  <p>
+    The <code>ConfigProvider</code> is a base interface for all configuration 
providers. Custom implementations of this interface can retrieve configuration 
data from various sources. You can then package and deploy the implementation 
as a JAR file and reference the provider's class in your configuration.
+  </p>
+  
+  <p><b>Example custom provider configuration</b></p>
+  <pre><code>config.providers=customProvider
+config.providers.customProvider.class=com.example.customProvider
+config.providers.customProvider.param1=value1
+config.providers.customProvider.param2=value2</code></pre>
+  
+  <h4 class="anchor-heading">
+    <a id="directory_config_provider" class="anchor-link"></a>
+    <a href="#directory_config_provider">DirectoryConfigProvider</a>
+  </h4>
+  
+  <p>
+    The <code>DirectoryConfigProvider</code> retrieves configuration data from 
files stored in a specified directory.
+  </p>
+  <p>
+    Each file represents a key, and its content is the value. You specify the 
path to the directory where the configuration files are stored using the 
<code>dir</code> parameter. This provider is useful for loading multiple 
configuration files and for organizing configuration data into separate files.
+  </p>
+  
+  <p><b>Example <code>DirectoryConfigProvider</code> configuration</b></p>
+  <pre><code>config.providers=dirProvider
+config.providers.dirProvider.class=org.apache.kafka.common.config.provider.DirectoryConfigProvider
+config.providers.dirProvider.param.dir=/path/to/config/directory</code></pre>
+  
+  <h4 class="anchor-heading">
+    <a id="env_var_config_provider" class="anchor-link"></a>
+    <a href="#env_var_config_provider">EnvVarConfigProvider</a>
+  </h4>
+  
+  <p>The <code>EnvVarConfigProvider</code> retrieves configuration data from 
environment variables.</p>
+  <p>No specific parameters are required, as it reads directly from the 
specified environment variables.</p>
+  <p>
+    This provider is useful for configuring applications running in 
containers, for example, to load certificates or JAAS configuration from 
environment variables mapped from secrets.
+  </p>
+  
+  <p><b>Example <code>EnvVarConfigProvider</code> configuration</b></p>
+  <pre><code>config.providers=envVarProvider
+config.providers.envVarProvider.class=org.apache.kafka.common.config.provider.EnvVarConfigProvider</code></pre>
+  
+  <h4 class="anchor-heading">
+    <a id="file_config_provider" class="anchor-link"></a>
+    <a href="#file_config_provider">FileConfigProvider</a>
+  </h4>
+  
+  <p>The <code>FileConfigProvider</code> retrieves configuration data from a 
single properties file.</p>
+  <p>You specify the path to the properties file using the <code>file</code> 
parameter.</p>
+  <p>This provider is useful for loading configuration data from mounted 
files.</p>
+  
+  <p><b>Example <code>FileConfigProvider</code> configuration</b></p>
+  <pre><code>config.providers=fileProvider
+config.providers.fileProvider.class=org.apache.kafka.common.config.provider.FileConfigProvider
+config.providers.fileProvider.param.file=/path/to/config.properties</code></pre>
+  
+  <h4 class="anchor-heading">
+    <a id="ref_config_provider" class="anchor-link"></a>
+    <a href="#ref_config_provider">Referencing configuration providers</a>
+  </h4>
+  <p>
+    To reference a property value supplied by a configuration provider, use 
the correct placeholder syntax:
+  </p>
+  <dl>
+    <dt><b><code>DirectoryConfigProvider</code></b></dt>
+    <dd>
+      <p><code>${dirProvider:&lt;path_to_file&gt;:&lt;file_name&gt;}</code></p>
+    </dd>
+    <dt><code><b>EnvVarConfigProvider</code></b></dt>
+    <dd>
+      <p><code>${envVarProvider:&lt;enVar_name&gt;}</code></p>
+    </dd>
+    
+    <dt><b><code>FileConfigProvider</code></b></dt>
+    <dd>
+      
<p><code>${fileProvider:&lt;path_and_filename&gt;:&lt;property&gt;}</code></p>
+    </dd>
+  </dl>
+  <p>
+    Here’s an example that uses a file configuration provider with Kafka 
Connect to provide authentication credentials to a database for a connector.
+  </p>
+  <p>
+    First, create a <code>connector-credentials.properties</code> 
configuration file with the following credentials:
+  </p>
+  <p><b>Example configuration file</b></p>

Review Comment:
   I think we can remove this paragraph. 



##########
docs/ops.html:
##########
@@ -1247,7 +1247,165 @@ <h4 class="anchor-heading"><a id="prodconfig" 
class="anchor-link"></a><a href="#
 
   Our client configuration varies a fair amount between different use cases.
 
-  <h3 class="anchor-heading"><a id="java" class="anchor-link"></a><a 
href="#java">6.6 Java Version</a></h3>
+  <h3 class="anchor-heading">
+    <a id="config_providers" class="anchor-link"></a>
+    <a href="#config_providers">6.6 Configuration Providers</a>
+  </h3>
+  
+  <p>
+    Use configuration providers to load configuration data from external 
sources. This might include sensitive information, such as passwords, API keys, 
or other credentials.
+  </p>
+  
+  <p>You have the following options:</p>
+  <ul>
+    <li>
+      Use a custom provider by creating a Java class implementing the
+      <a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/ConfigProvider.html"><code>ConfigProvider</code></a>
 interface and packaging it into a JAR file.
+    </li>
+    <li>Use a built-in provider:</li>
+    <ul>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/DirectoryConfigProvider.html"><code>DirectoryConfigProvider</code></a></li>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/EnvVarConfigProvider.html"><code>EnvVarConfigProvider</code></a></li>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/FileConfigProvider.html"><code>FileConfigProvider</code></a></li>
+    </ul>
+  </ul>
+  
+  <p>
+    To use a configuration provider, specify it in your configuration file 
using the <code>config.providers</code> property. 
+  </p>
+  <p>
+    Each provider can have its own set of parameters, which are passed in a 
specific format.
+  </p>
+  
+  <h4 class="anchor-heading">
+    <a id="common_provider_params" class="anchor-link"></a>
+    <a href="#common_provider_params">Common Parameters</a>

Review Comment:
   What about renaming this to something like "Using Configuration Providers"? 
as effectively this describe how to use them.



##########
docs/ops.html:
##########
@@ -1247,7 +1247,165 @@ <h4 class="anchor-heading"><a id="prodconfig" 
class="anchor-link"></a><a href="#
 
   Our client configuration varies a fair amount between different use cases.
 
-  <h3 class="anchor-heading"><a id="java" class="anchor-link"></a><a 
href="#java">6.6 Java Version</a></h3>
+  <h3 class="anchor-heading">
+    <a id="config_providers" class="anchor-link"></a>
+    <a href="#config_providers">6.6 Configuration Providers</a>
+  </h3>
+  
+  <p>
+    Use configuration providers to load configuration data from external 
sources. This might include sensitive information, such as passwords, API keys, 
or other credentials.
+  </p>
+  
+  <p>You have the following options:</p>
+  <ul>
+    <li>
+      Use a custom provider by creating a Java class implementing the
+      <a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/ConfigProvider.html"><code>ConfigProvider</code></a>
 interface and packaging it into a JAR file.
+    </li>
+    <li>Use a built-in provider:</li>
+    <ul>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/DirectoryConfigProvider.html"><code>DirectoryConfigProvider</code></a></li>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/EnvVarConfigProvider.html"><code>EnvVarConfigProvider</code></a></li>
+      <li><a 
href="/{{version}}/javadoc/org/apache/kafka/common/config/provider/FileConfigProvider.html"><code>FileConfigProvider</code></a></li>
+    </ul>
+  </ul>
+  
+  <p>
+    To use a configuration provider, specify it in your configuration file 
using the <code>config.providers</code> property. 
+  </p>
+  <p>
+    Each provider can have its own set of parameters, which are passed in a 
specific format.
+  </p>
+  
+  <h4 class="anchor-heading">
+    <a id="common_provider_params" class="anchor-link"></a>
+    <a href="#common_provider_params">Common Parameters</a>
+  </h4>
+  
+  <p>All configuration providers share a common way of passing parameters.</p>
+  <p>
+    You specify a comma-separated list of aliases and the fully-specified 
class that implements the configuration provider:
+  </p>
+  <pre><code>config.providers=provider1,provider2
+config.providers.provider1.class=com.example.Provider1
+config.providers.provider2.class=com.example.Provider2</code></pre>
+  <p>
+    Pass additional parameters to each provider as 
<code>config.providers.&lt;provider_alias&gt;.&lt;parameter_key&gt;=&lt;parameter_value&gt;</code>:
+  </p>
+  <pre><code>config.providers.provider1.param1=value1
+config.providers.provider1.param2=value2</code></pre>
+  
+  <h4 class="anchor-heading">
+    <a id="config_provider" class="anchor-link"></a>
+    <a href="#config_provider">ConfigProvider</a>
+  </h4>
+  
+  <p>
+    The <code>ConfigProvider</code> is a base interface for all configuration 
providers. Custom implementations of this interface can retrieve configuration 
data from various sources. You can then package and deploy the implementation 
as a JAR file and reference the provider's class in your configuration.
+  </p>
+  
+  <p><b>Example custom provider configuration</b></p>
+  <pre><code>config.providers=customProvider
+config.providers.customProvider.class=com.example.customProvider
+config.providers.customProvider.param1=value1
+config.providers.customProvider.param2=value2</code></pre>
+  
+  <h4 class="anchor-heading">
+    <a id="directory_config_provider" class="anchor-link"></a>
+    <a href="#directory_config_provider">DirectoryConfigProvider</a>
+  </h4>
+  
+  <p>
+    The <code>DirectoryConfigProvider</code> retrieves configuration data from 
files stored in a specified directory.
+  </p>
+  <p>
+    Each file represents a key, and its content is the value. You specify the 
path to the directory where the configuration files are stored using the 
<code>dir</code> parameter. This provider is useful for loading multiple 
configuration files and for organizing configuration data into separate files.
+  </p>
+  
+  <p><b>Example <code>DirectoryConfigProvider</code> configuration</b></p>
+  <pre><code>config.providers=dirProvider
+config.providers.dirProvider.class=org.apache.kafka.common.config.provider.DirectoryConfigProvider
+config.providers.dirProvider.param.dir=/path/to/config/directory</code></pre>
+  
+  <h4 class="anchor-heading">
+    <a id="env_var_config_provider" class="anchor-link"></a>
+    <a href="#env_var_config_provider">EnvVarConfigProvider</a>
+  </h4>
+  
+  <p>The <code>EnvVarConfigProvider</code> retrieves configuration data from 
environment variables.</p>
+  <p>No specific parameters are required, as it reads directly from the 
specified environment variables.</p>
+  <p>
+    This provider is useful for configuring applications running in 
containers, for example, to load certificates or JAAS configuration from 
environment variables mapped from secrets.
+  </p>
+  
+  <p><b>Example <code>EnvVarConfigProvider</code> configuration</b></p>
+  <pre><code>config.providers=envVarProvider
+config.providers.envVarProvider.class=org.apache.kafka.common.config.provider.EnvVarConfigProvider</code></pre>
+  
+  <h4 class="anchor-heading">
+    <a id="file_config_provider" class="anchor-link"></a>
+    <a href="#file_config_provider">FileConfigProvider</a>
+  </h4>
+  
+  <p>The <code>FileConfigProvider</code> retrieves configuration data from a 
single properties file.</p>
+  <p>You specify the path to the properties file using the <code>file</code> 
parameter.</p>
+  <p>This provider is useful for loading configuration data from mounted 
files.</p>
+  
+  <p><b>Example <code>FileConfigProvider</code> configuration</b></p>
+  <pre><code>config.providers=fileProvider
+config.providers.fileProvider.class=org.apache.kafka.common.config.provider.FileConfigProvider
+config.providers.fileProvider.param.file=/path/to/config.properties</code></pre>
+  
+  <h4 class="anchor-heading">
+    <a id="ref_config_provider" class="anchor-link"></a>
+    <a href="#ref_config_provider">Referencing configuration providers</a>
+  </h4>
+  <p>
+    To reference a property value supplied by a configuration provider, use 
the correct placeholder syntax:
+  </p>
+  <dl>
+    <dt><b><code>DirectoryConfigProvider</code></b></dt>
+    <dd>
+      <p><code>${dirProvider:&lt;path_to_file&gt;:&lt;file_name&gt;}</code></p>
+    </dd>
+    <dt><code><b>EnvVarConfigProvider</code></b></dt>
+    <dd>
+      <p><code>${envVarProvider:&lt;enVar_name&gt;}</code></p>
+    </dd>
+    
+    <dt><b><code>FileConfigProvider</code></b></dt>
+    <dd>
+      
<p><code>${fileProvider:&lt;path_and_filename&gt;:&lt;property&gt;}</code></p>
+    </dd>
+  </dl>
+  <p>
+    Here’s an example that uses a file configuration provider with Kafka 
Connect to provide authentication credentials to a database for a connector.
+  </p>
+  <p>
+    First, create a <code>connector-credentials.properties</code> 
configuration file with the following credentials:
+  </p>
+  <p><b>Example configuration file</b></p>
+<pre><code>dbUsername=my-username
+dbPassword=my-password</code></pre>
+  <p><em>NOTE: Ensure the appropriate permissions are set for securely 
accessing the properties file.
+    For additional security, consider encrypting sensitive information using a 
secret and implementing decryption in your application at runtime.

Review Comment:
   This tip is not really applicable so I wonder if we drop it. If you're using 
a configuration provider to provide JAAS credentials for a consumer for 
example, you can't have some runtime decryption logic. The retrieved values 
from the provider are directly used.



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