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// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.hosted.node.admin.task.util.systemd;
import com.yahoo.vespa.hosted.node.admin.component.TaskContext;
import com.yahoo.vespa.hosted.node.admin.task.util.process.Terminal;
import java.util.Objects;
import java.util.logging.Logger;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Control the systemd system and service manager
*
* @author hakonhall
*/
public class SystemCtl {
private static final Logger logger = Logger.getLogger(SystemCtl.class.getName());
// Valid systemd property names from looking at a couple of services.
private static final Pattern PROPERTY_NAME_PATTERN = Pattern.compile("^[a-zA-Z]+$");
// Last line of `systemctl list-unit-files <unit>` prints '0 unit files listed.'
private static final Pattern UNIT_FILES_LISTED_PATTERN = Pattern.compile("([0-9]+) unit files listed\\.");
// Patterns matching properties output by the 'systemctl show' command.
private static final Pattern UNIT_FILE_STATE_PROPERTY_PATTERN = createPropertyPattern("UnitFileState");
private static final Pattern ACTIVE_STATE_PROPERTY_PATTERN = createPropertyPattern("ActiveState");
private final Terminal terminal;
private static Pattern createPropertyPattern(String propertyName) {
if (!PROPERTY_NAME_PATTERN.matcher(propertyName).matches()) {
throw new IllegalArgumentException("Property name does not match " + PROPERTY_NAME_PATTERN);
}
// Make ^ and $ match beginning and end of lines.
String regex = String.format("(?md)^%s=(.*)$", propertyName);
return Pattern.compile(regex);
}
public SystemCtl(Terminal terminal) {
this.terminal = terminal;
}
public void daemonReload(TaskContext taskContext) {
terminal.newCommandLine(taskContext)
.add("systemctl", "daemon-reload")
.execute();
}
public SystemCtlEnable enable(String unit) { return new SystemCtlEnable(unit); }
public SystemCtlDisable disable(String unit) { return new SystemCtlDisable(unit); }
public SystemCtlStart start(String unit) { return new SystemCtlStart(unit); }
public SystemCtlStop stop(String unit) { return new SystemCtlStop(unit); }
public SystemCtlRestart restart(String unit) { return new SystemCtlRestart(unit); }
public boolean serviceExists(TaskContext context, String unit) {
return terminal.newCommandLine(context)
.add("systemctl").add("list-unit-files").add(unit + ".service").executeSilently()
.mapOutput(output -> {
// Last line of the form: "1 unit files listed."
Matcher matcher = UNIT_FILES_LISTED_PATTERN.matcher(output);
if (!matcher.find()) {
throw new IllegalArgumentException();
}
return !matcher.group(1).equals("0");
});
}
public class SystemCtlEnable extends SystemCtlCommand {
private SystemCtlEnable(String unit) {
super("enable", unit);
}
protected boolean isAlreadyConverged(TaskContext context) {
String unitFileState = getSystemCtlProperty(context, UNIT_FILE_STATE_PROPERTY_PATTERN);
return Objects.equals(unitFileState, "enabled");
}
}
public class SystemCtlDisable extends SystemCtlCommand {
private SystemCtlDisable(String unit) {
super("disable", unit);
}
protected boolean isAlreadyConverged(TaskContext context) {
String unitFileState = getSystemCtlProperty(context, UNIT_FILE_STATE_PROPERTY_PATTERN);
return Objects.equals(unitFileState, "disabled");
}
}
public class SystemCtlStart extends SystemCtlCommand {
private SystemCtlStart(String unit) {
super("start", unit);
}
protected boolean isAlreadyConverged(TaskContext context) {
String activeState = getSystemCtlProperty(context, ACTIVE_STATE_PROPERTY_PATTERN);
return Objects.equals(activeState, "active");
}
}
public class SystemCtlStop extends SystemCtlCommand {
private SystemCtlStop(String unit) {
super("stop", unit);
}
protected boolean isAlreadyConverged(TaskContext context) {
String activeState = getSystemCtlProperty(context, ACTIVE_STATE_PROPERTY_PATTERN);
return Objects.equals(activeState, "inactive");
}
}
public class SystemCtlRestart extends SystemCtlCommand {
private SystemCtlRestart(String unit) {
super("restart", unit);
}
protected boolean isAlreadyConverged(TaskContext context) {
return false;
}
}
public abstract class SystemCtlCommand {
private final String command;
private final String unit;
private SystemCtlCommand(String command, String unit) {
this.command = command;
this.unit = unit;
}
protected abstract boolean isAlreadyConverged(TaskContext context);
public boolean converge(TaskContext context) {
if (isAlreadyConverged(context)) {
return false;
}
terminal.newCommandLine(context)
.add("systemctl", command, unit)
.execute();
return true;
}
/**
* @param propertyPattern Pattern to match the output of systemctl show command with
* exactly 1 group. The matchng group must exist.
* @return The matched group from the 'systemctl show' output.
*/
protected String getSystemCtlProperty(TaskContext context, Pattern propertyPattern) {
return terminal.newCommandLine(context)
.add("systemctl", "show", unit)
.executeSilently()
.mapOutput(output -> extractProperty(output, propertyPattern));
}
}
/**
* Find the systemd property value of the property (given by propertyPattern)
* matching the 'systemctl show' output (given by showProcess).
*/
private static String extractProperty(String showOutput, Pattern propertyPattern) {
Matcher matcher = propertyPattern.matcher(showOutput);
if (!matcher.find()) {
throw new IllegalArgumentException("Pattern '" + propertyPattern +
"' didn't match output");
} else if (matcher.groupCount() != 1) {
throw new IllegalArgumentException("Property pattern must have exactly 1 group");
}
return matcher.group(1);
}
}
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