CommonAuditContext (Apache Hadoop Main 3.4.1 API)

java.lang.Object
- org.apache.hadoop.fs.audit.CommonAuditContext

```
@InterfaceAudience.Public
 @InterfaceStability.Unstable
public final class CommonAuditContext
extends Object
```
The common audit context is a map of common context information which can be used with any audit span. This context is shared across all Filesystems within the thread. Audit spans will be created with a reference to the current context of their thread; That reference is retained even as they are moved across threads, so context information (including thread ID Java runtime). The Global context entries are a set of key-value pairs which span all threads; the HttpReferrerAuditHeader picks these up automatically. It is intended for minimal use of shared constant values (process ID, entry point). An attribute set in setGlobalContextEntry(String, String) will be set across all audit spans in all threads. The noteEntryPoint(Object) method should be used in entry points (ToolRunner.run, etc). It extracts the final element of the classname and attaches that to the global context with the attribute key AuditConstants.PARAM_COMMAND, if not already set. This helps identify the application being executued. All other values set are specific to this context, which is thread local. The attributes which can be added to ths common context include evaluator methods which will be evaluated in whichever thread invokes getEvaluatedEntries() and then evaluates them. That map of evaluated options may evaluated later, in a different thread. For setting and clearing thread-level options, use currentAuditContext() to get the thread-local context for the caller, which can then be manipulated. For further information, especially related to memory consumption, read the document `auditing_architecture` in the `hadoop-aws` module.

Field Summary

Fields
Modifier and Type Field and Description

static String PROCESS_ID
Process ID; currently built from UUID and timestamp.

Fields
Modifier and Type	Field and Description
`static String`	`PROCESS_ID` Process ID; currently built from UUID and timestamp.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`containsKey(String key)` Does the context contain a specific key?
`static CommonAuditContext`	`currentAuditContext()` Get the current common audit context.
`static String`	`currentThreadID()` A thread ID which is unique for this process and shared across all S3A clients on the same thread, even those using different FS instances.
`String`	`get(String key)` Get a context entry.
`Map<String,Supplier<String>>`	`getEvaluatedEntries()` Get the evaluated operations.
`static Iterable<Map.Entry<String,String>>`	`getGlobalContextEntries()` Get an iterator over the global entries.
`static String`	`getGlobalContextEntry(String key)` Get a global entry.
`static void`	`noteEntryPoint(Object tool)` Add the entry point as a context entry with the key `AuditConstants.PARAM_COMMAND` if it has not already been recorded.
`Supplier<String>`	`put(String key, String value)` Put a context entry.
`Supplier<String>`	`put(String key, Supplier<String> value)` Put a context entry dynamically evaluated on demand.
`void`	`remove(String key)` Remove a context entry.
`static void`	`removeGlobalContextEntry(String key)` Remove a global entry.
`void`	`reset()` Rest the context; will set the standard options again.
`static void`	`setGlobalContextEntry(String key, String value)` Set a global entry.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - PROCESS_ID
```
public static final String PROCESS_ID
```
    Process ID; currently built from UUID and timestamp.
- Method Detail
  - put
```
public Supplier<String> put(String key,
                            String value)
```
    Put a context entry.
    
    Parameters:
    
    key - key
    
    value - new value., If null, triggers removal.
    
    Returns:
    
    old value or null
  - put
```
public Supplier<String> put(String key,
                            Supplier<String> value)
```
    Put a context entry dynamically evaluated on demand. Important: as these supplier methods are long-lived, the supplier function MUST NOT be part of/refer to any object instance of significant memory size. Applications SHOULD remove references when they are no longer needed. When logged at TRACE, prints the key and stack trace of the caller, to allow for debugging of any problems.
    
    Parameters:
    
    key - key
    
    value - new value
    
    Returns:
    
    old value or null
  - remove
```
public void remove(String key)
```
    Remove a context entry.
    
    Parameters:
    
    key - key
  - get
```
public String get(String key)
```
    Get a context entry.
    
    Parameters:
    
    key - key
    
    Returns:
    
    value or null
  - reset
```
public void reset()
```
    Rest the context; will set the standard options again. Primarily for testing.
  - containsKey
```
public boolean containsKey(String key)
```
    Does the context contain a specific key?
    
    Parameters:
    
    key - key
    
    Returns:
    
    true if it is in the context.
  - currentAuditContext
```
public static CommonAuditContext currentAuditContext()
```
    Get the current common audit context. Thread local.
    
    Returns:
    
    the audit context of this thread.
  - currentThreadID
```
public static String currentThreadID()
```
    A thread ID which is unique for this process and shared across all S3A clients on the same thread, even those using different FS instances.
    
    Returns:
    
    a thread ID for reporting.
  - getEvaluatedEntries
```
public Map<String,Supplier<String>> getEvaluatedEntries()
```
    Get the evaluated operations. This is the map unique to this context.
    
    Returns:
    
    the operations map.
  - setGlobalContextEntry
```
public static void setGlobalContextEntry(String key,
                                         String value)
```
    Set a global entry.
    
    Parameters:
    
    key - key
    
    value - value
  - getGlobalContextEntry
```
public static String getGlobalContextEntry(String key)
```
    Get a global entry.
    
    Parameters:
    
    key - key
    
    Returns:
    
    value or null
  - removeGlobalContextEntry
```
public static void removeGlobalContextEntry(String key)
```
    Remove a global entry.
    
    Parameters:
    
    key - key to clear.
  - noteEntryPoint
```
public static void noteEntryPoint(Object tool)
```
    Add the entry point as a context entry with the key AuditConstants.PARAM_COMMAND if it has not already been recorded. This is called via ToolRunner but may be used at any other entry point.
    
    Parameters:
    
    tool - object loaded/being launched.
  - getGlobalContextEntries
```
public static Iterable<Map.Entry<String,String>> getGlobalContextEntries()
```
    Get an iterator over the global entries. Thread safe.
    
    Returns:
    
    an iterable to enumerate the values.

Class CommonAuditContext

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

PROCESS_ID

Method Detail

put

put

remove

get

reset

containsKey

currentAuditContext

currentThreadID

getEvaluatedEntries

setGlobalContextEntry

getGlobalContextEntry

removeGlobalContextEntry

noteEntryPoint

getGlobalContextEntries