Package org.apache.unomi.shell.migration.service

Class MigrationContext

java.lang.Object

org.apache.unomi.shell.migration.service.MigrationContext

public class MigrationContext
extends Object

This class is instantiated for each migration process, it contains useful methods to handle the current migration lifecycle. This class allow for keeping track of the migration steps by persisting the steps and there state on the FileSystem, allowing for a migration to be able to restart from a failure in case it happens. This class allow also for logging the migration informations depending on the current context: - if executed in karaf shell using a karaf shell session, then the logging will be done in the shell console - if executed outside karaf shell using OSGI service direct, then the logging will be done using classical logger systems This class allow also to do a best effort on missing configuration information, by prompting questions in the karaf shell (not supported in case direct OSGI service usage)

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	MigrationContext.MigrationStep	A simple migration step to be performed

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	MigrationContext(org.apache.karaf.shell.api.console.Session session, MigrationConfig migrationConfig)

Method Summary

Modifier and Type	Method	Description
String	askUserWithAuthorizedAnswer(String msg, List<String> authorizedAnswer)	This method allow you to ask a question to the user.
String	askUserWithDefaultAnswer(String msg, String defaultAnswer)	This will ask a question to the user and return the default answer if the user does not answer.
protected void	cleanHistory()	Clean history from FileSystem
boolean	getConfigBoolean(String name)	Get config for property name, in case the property doesn't exist on file system config file Best effort will be made to prompt question in karaf shell to get the needed information
String	getConfigString(String name)	Get config for property name, in case the property doesn't exist on file system config file Best effort will be made to prompt question in karaf shell to get the needed information
org.apache.http.impl.client.CloseableHttpClient	getHttpClient()	This HTTP client is configured to be used for ElasticSearch requests to be able to perform migrations requests.
void	performMigrationStep(String stepKey, MigrationContext.MigrationStep step)	this method allow for migration step execution: - in case the history already contains the given stepKey as COMPLETED, then the step won't be executed - in case the history doesn't contain the given stepKey, then the step will be executed Also this method is keeping track of the history by persisting it on the FileSystem.
void	printException(String msg)	Same as above without stacktrace
void	printException(String msg, Throwable t)	Print an exception along with a message in the console.
void	printMessage(String msg)	Print a message in the console.
String	promptMessageToUser(String msg)	This method allow you to prompt a message to the user.
protected void	setHttpClient(org.apache.http.impl.client.CloseableHttpClient httpClient)
protected void	tryRecoverFromHistory()	Try to recover from a previous run I case we found an existing history we will ask if we want to recover or if we want to restart from the beginning (it is also configurable using the conf: recoverFromHistory)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MigrationContext

protected MigrationContext(org.apache.karaf.shell.api.console.Session session,
                           MigrationConfig migrationConfig)

Method Detail

tryRecoverFromHistory

protected void tryRecoverFromHistory()
                              throws IOException

Try to recover from a previous run I case we found an existing history we will ask if we want to recover or if we want to restart from the beginning (it is also configurable using the conf: recoverFromHistory)

Throws:

IOException

performMigrationStep

public void performMigrationStep(String stepKey,
                                 MigrationContext.MigrationStep step)
                          throws Exception

this method allow for migration step execution: - in case the history already contains the given stepKey as COMPLETED, then the step won't be executed - in case the history doesn't contain the given stepKey, then the step will be executed Also this method is keeping track of the history by persisting it on the FileSystem.

Parameters:

stepKey - the key of the given step

step - the step to be performed

Throws:

IOException

Exception

cleanHistory

protected void cleanHistory()
                     throws IOException

Clean history from FileSystem

Throws:

IOException

askUserWithDefaultAnswer

public String askUserWithDefaultAnswer(String msg,
                                       String defaultAnswer)
                                throws IOException

This will ask a question to the user and return the default answer if the user does not answer.

Parameters:

msg - String message to ask

defaultAnswer - String default answer

Returns:

the user's answer

Throws:

IOException - if there was a problem reading input from the console

askUserWithAuthorizedAnswer

public String askUserWithAuthorizedAnswer(String msg,
                                          List<String> authorizedAnswer)
                                   throws IOException

This method allow you to ask a question to the user. The answer is controlled before being return so the question will be ask until the user enter one the authorized answer

Parameters:

msg - String message to ask

authorizedAnswer - Array of possible answer, all answer must be in lower case

Returns:

the user answer

Throws:

IOException - if there was an error retrieving an answer from the user on the console

promptMessageToUser

public String promptMessageToUser(String msg)

This method allow you to prompt a message to the user. No control is done on the answer provided by the user.

Parameters:

msg - String message to prompt

Returns:

the user answer

printMessage

public void printMessage(String msg)

Print a message in the console.

Parameters:

msg - the message to print out with a newline

printException

public void printException(String msg,
                           Throwable t)

Print an exception along with a message in the console.

Parameters:

msg - the message to print out with a newline

t - the exception to dump in the shell console after the message

printException

public void printException(String msg)

Same as above without stacktrace

Parameters:

msg - the message to print out with a newline

getConfigString

public String getConfigString(String name)
                       throws IOException

Get config for property name, in case the property doesn't exist on file system config file Best effort will be made to prompt question in karaf shell to get the needed information

Parameters:

name - the name of the property

Returns:

the value of the property

Throws:

IOException

getConfigBoolean

public boolean getConfigBoolean(String name)
                         throws IOException

Get config for property name, in case the property doesn't exist on file system config file Best effort will be made to prompt question in karaf shell to get the needed information

Parameters:

name - the name of the property

Returns:

the value of the property

Throws:

IOException

getHttpClient

public org.apache.http.impl.client.CloseableHttpClient getHttpClient()

This HTTP client is configured to be used for ElasticSearch requests to be able to perform migrations requests.

Returns:

the http client.

setHttpClient

protected void setHttpClient(org.apache.http.impl.client.CloseableHttpClient httpClient)