聊聊flink的ParameterTool

序

本文主要研究一下flink的ParameterTool

实例

fromPropertiesFile

String propertiesFilePath = "/home/sam/flink/myjob.properties";
ParameterTool parameter = ParameterTool.fromPropertiesFile(propertiesFilePath);

File propertiesFile = new File(propertiesFilePath);
ParameterTool parameter = ParameterTool.fromPropertiesFile(propertiesFile);

InputStream propertiesFileInputStream = new FileInputStream(file);
ParameterTool parameter = ParameterTool.fromPropertiesFile(propertiesFileInputStream);

• 使用ParameterTool.fromPropertiesFile从.properties文件创建ParameterTool

fromArgs

public static void main(String[] args) {
    ParameterTool parameter = ParameterTool.fromArgs(args);
    // .. regular code ..
}

• 使用ParameterTool.fromArgs从命令行创建ParameterTool(比如--input hdfs:///mydata --elements 42)

fromSystemProperties

ParameterTool parameter = ParameterTool.fromSystemProperties();

• 使用ParameterTool.fromSystemProperties从system properties创建ParameterTool(比如-Dinput=hdfs:///mydata)

获取参数值

ParameterTool parameters = // ...
parameter.getRequired("input");
parameter.get("output", "myDefaultValue");
parameter.getLong("expectedCount", -1L);
parameter.getNumberOfParameters()
// .. there are more methods available.

• 可以使用ParameterTool的get、getRequired、getLong等方法获取参数值

设置为global

env.getConfig().setGlobalJobParameters(parameters);

public static final class Tokenizer extends RichFlatMapFunction<String, Tuple2<String, Integer>> {

    @Override
    public void flatMap(String value, Collector<Tuple2<String, Integer>> out) {
    ParameterTool parameters = (ParameterTool)
        getRuntimeContext().getExecutionConfig().getGlobalJobParameters();
    parameters.getRequired("input");
    // ... do more ...
}

• 使用env.getConfig().setGlobalJobParameters将ParameterTool的访问范围设置为global

GlobalJobParameters

flink-core-1.7.1-sources.jar!/org/apache/flink/api/common/ExecutionConfig.java

    public static class GlobalJobParameters implements Serializable {
        private static final long serialVersionUID = 1L;

        /**
         * Convert UserConfig into a {@code Map<String, String>} representation.
         * This can be used by the runtime, for example for presenting the user config in the web frontend.
         *
         * @return Key/Value representation of the UserConfig
         */
        public Map<String, String> toMap() {
            return Collections.emptyMap();
        }
    }

• GlobalJobParameters里头有一个toMap方法，返回Collections.emptyMap()

ParameterTool

flink-java-1.7.1-sources.jar!/org/apache/flink/api/java/utils/ParameterTool.java

@Public
public class ParameterTool extends ExecutionConfig.GlobalJobParameters implements Serializable, Cloneable {
    private static final long serialVersionUID = 1L;

    protected static final String NO_VALUE_KEY = "__NO_VALUE_KEY";
    protected static final String DEFAULT_UNDEFINED = "<undefined>";

    //......

    // ------------------ ParameterUtil  ------------------------
    protected final Map<String, String> data;

    // data which is only used on the client and does not need to be transmitted
    protected transient Map<String, String> defaultData;
    protected transient Set<String> unrequestedParameters;

    private ParameterTool(Map<String, String> data) {
        this.data = Collections.unmodifiableMap(new HashMap<>(data));

        this.defaultData = new ConcurrentHashMap<>(data.size());

        this.unrequestedParameters = Collections.newSetFromMap(new ConcurrentHashMap<>(data.size()));

        unrequestedParameters.addAll(data.keySet());
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        ParameterTool that = (ParameterTool) o;
        return Objects.equals(data, that.data) &&
            Objects.equals(defaultData, that.defaultData) &&
            Objects.equals(unrequestedParameters, that.unrequestedParameters);
    }

    @Override
    public int hashCode() {
        return Objects.hash(data, defaultData, unrequestedParameters);
    }

    @Override
    public Map<String, String> toMap() {
        return data;
    }

    //......

        /**
     * Returns {@link ParameterTool} for the given arguments. The arguments are keys followed by values.
     * Keys have to start with '-' or '--'
     *
     * <p><strong>Example arguments:</strong>
     * --key1 value1 --key2 value2 -key3 value3
     *
     * @param args Input array arguments
     * @return A {@link ParameterTool}
     */
    public static ParameterTool fromArgs(String[] args) {
        final Map<String, String> map = new HashMap<>(args.length / 2);

        int i = 0;
        while (i < args.length) {
            final String key;

            if (args[i].startsWith("--")) {
                key = args[i].substring(2);
            } else if (args[i].startsWith("-")) {
                key = args[i].substring(1);
            } else {
                throw new IllegalArgumentException(
                    String.format("Error parsing arguments '%s' on '%s'. Please prefix keys with -- or -.",
                        Arrays.toString(args), args[i]));
            }

            if (key.isEmpty()) {
                throw new IllegalArgumentException(
                    "The input " + Arrays.toString(args) + " contains an empty argument");
            }

            i += 1; // try to find the value

            if (i >= args.length) {
                map.put(key, NO_VALUE_KEY);
            } else if (NumberUtils.isNumber(args[i])) {
                map.put(key, args[i]);
                i += 1;
            } else if (args[i].startsWith("--") || args[i].startsWith("-")) {
                // the argument cannot be a negative number because we checked earlier
                // -> the next argument is a parameter name
                map.put(key, NO_VALUE_KEY);
            } else {
                map.put(key, args[i]);
                i += 1;
            }
        }

        return fromMap(map);
    }

    /**
     * Returns {@link ParameterTool} for the given {@link Properties} file.
     *
     * @param path Path to the properties file
     * @return A {@link ParameterTool}
     * @throws IOException If the file does not exist
     * @see Properties
     */
    public static ParameterTool fromPropertiesFile(String path) throws IOException {
        File propertiesFile = new File(path);
        return fromPropertiesFile(propertiesFile);
    }

    /**
     * Returns {@link ParameterTool} for the given {@link Properties} file.
     *
     * @param file File object to the properties file
     * @return A {@link ParameterTool}
     * @throws IOException If the file does not exist
     * @see Properties
     */
    public static ParameterTool fromPropertiesFile(File file) throws IOException {
        if (!file.exists()) {
            throw new FileNotFoundException("Properties file " + file.getAbsolutePath() + " does not exist");
        }
        try (FileInputStream fis = new FileInputStream(file)) {
            return fromPropertiesFile(fis);
        }
    }

    /**
     * Returns {@link ParameterTool} for the given InputStream from {@link Properties} file.
     *
     * @param inputStream InputStream from the properties file
     * @return A {@link ParameterTool}
     * @throws IOException If the file does not exist
     * @see Properties
     */
    public static ParameterTool fromPropertiesFile(InputStream inputStream) throws IOException {
        Properties props = new Properties();
        props.load(inputStream);
        return fromMap((Map) props);
    }

    /**
     * Returns {@link ParameterTool} for the given map.
     *
     * @param map A map of arguments. Both Key and Value have to be Strings
     * @return A {@link ParameterTool}
     */
    public static ParameterTool fromMap(Map<String, String> map) {
        Preconditions.checkNotNull(map, "Unable to initialize from empty map");
        return new ParameterTool(map);
    }

    /**
     * Returns {@link ParameterTool} from the system properties.
     * Example on how to pass system properties:
     * -Dkey1=value1 -Dkey2=value2
     *
     * @return A {@link ParameterTool}
     */
    public static ParameterTool fromSystemProperties() {
        return fromMap((Map) System.getProperties());
    }

    //......

    /**
     * Returns the String value for the given key.
     * If the key does not exist it will return null.
     */
    public String get(String key) {
        addToDefaults(key, null);
        unrequestedParameters.remove(key);
        return data.get(key);
    }

    /**
     * Returns the String value for the given key.
     * If the key does not exist it will throw a {@link RuntimeException}.
     */
    public String getRequired(String key) {
        addToDefaults(key, null);
        String value = get(key);
        if (value == null) {
            throw new RuntimeException("No data for required key '" + key + "'");
        }
        return value;
    }

    /**
     * Returns the String value for the given key.
     * If the key does not exist it will return the given default value.
     */
    public String get(String key, String defaultValue) {
        addToDefaults(key, defaultValue);
        String value = get(key);
        if (value == null) {
            return defaultValue;
        } else {
            return value;
        }
    }

    /**
     * Check if value is set.
     */
    public boolean has(String value) {
        addToDefaults(value, null);
        unrequestedParameters.remove(value);
        return data.containsKey(value);
    }

    // -------------- Integer

    /**
     * Returns the Integer value for the given key.
     * The method fails if the key does not exist or the value is not an Integer.
     */
    public int getInt(String key) {
        addToDefaults(key, null);
        String value = getRequired(key);
        return Integer.parseInt(value);
    }

    /**
     * Returns the Integer value for the given key. If the key does not exists it will return the default value given.
     * The method fails if the value is not an Integer.
     */
    public int getInt(String key, int defaultValue) {
        addToDefaults(key, Integer.toString(defaultValue));
        String value = get(key);
        if (value == null) {
            return defaultValue;
        }
        return Integer.parseInt(value);
    }

    // -------------- LONG

    /**
     * Returns the Long value for the given key.
     * The method fails if the key does not exist.
     */
    public long getLong(String key) {
        addToDefaults(key, null);
        String value = getRequired(key);
        return Long.parseLong(value);
    }

    /**
     * Returns the Long value for the given key. If the key does not exists it will return the default value given.
     * The method fails if the value is not a Long.
     */
    public long getLong(String key, long defaultValue) {
        addToDefaults(key, Long.toString(defaultValue));
        String value = get(key);
        if (value == null) {
            return defaultValue;
        }
        return Long.parseLong(value);
    }

    // -------------- FLOAT

    /**
     * Returns the Float value for the given key.
     * The method fails if the key does not exist.
     */
    public float getFloat(String key) {
        addToDefaults(key, null);
        String value = getRequired(key);
        return Float.valueOf(value);
    }

    /**
     * Returns the Float value for the given key. If the key does not exists it will return the default value given.
     * The method fails if the value is not a Float.
     */
    public float getFloat(String key, float defaultValue) {
        addToDefaults(key, Float.toString(defaultValue));
        String value = get(key);
        if (value == null) {
            return defaultValue;
        } else {
            return Float.valueOf(value);
        }
    }

    // -------------- DOUBLE

    /**
     * Returns the Double value for the given key.
     * The method fails if the key does not exist.
     */
    public double getDouble(String key) {
        addToDefaults(key, null);
        String value = getRequired(key);
        return Double.valueOf(value);
    }

    /**
     * Returns the Double value for the given key. If the key does not exists it will return the default value given.
     * The method fails if the value is not a Double.
     */
    public double getDouble(String key, double defaultValue) {
        addToDefaults(key, Double.toString(defaultValue));
        String value = get(key);
        if (value == null) {
            return defaultValue;
        } else {
            return Double.valueOf(value);
        }
    }

    // -------------- BOOLEAN

    /**
     * Returns the Boolean value for the given key.
     * The method fails if the key does not exist.
     */
    public boolean getBoolean(String key) {
        addToDefaults(key, null);
        String value = getRequired(key);
        return Boolean.valueOf(value);
    }

    /**
     * Returns the Boolean value for the given key. If the key does not exists it will return the default value given.
     * The method returns whether the string of the value is "true" ignoring cases.
     */
    public boolean getBoolean(String key, boolean defaultValue) {
        addToDefaults(key, Boolean.toString(defaultValue));
        String value = get(key);
        if (value == null) {
            return defaultValue;
        } else {
            return Boolean.valueOf(value);
        }
    }

    // -------------- SHORT

    /**
     * Returns the Short value for the given key.
     * The method fails if the key does not exist.
     */
    public short getShort(String key) {
        addToDefaults(key, null);
        String value = getRequired(key);
        return Short.valueOf(value);
    }

    /**
     * Returns the Short value for the given key. If the key does not exists it will return the default value given.
     * The method fails if the value is not a Short.
     */
    public short getShort(String key, short defaultValue) {
        addToDefaults(key, Short.toString(defaultValue));
        String value = get(key);
        if (value == null) {
            return defaultValue;
        } else {
            return Short.valueOf(value);
        }
    }

    // -------------- BYTE

    /**
     * Returns the Byte value for the given key.
     * The method fails if the key does not exist.
     */
    public byte getByte(String key) {
        addToDefaults(key, null);
        String value = getRequired(key);
        return Byte.valueOf(value);
    }

    /**
     * Returns the Byte value for the given key. If the key does not exists it will return the default value given.
     * The method fails if the value is not a Byte.
     */
    public byte getByte(String key, byte defaultValue) {
        addToDefaults(key, Byte.toString(defaultValue));
        String value = get(key);
        if (value == null) {
            return defaultValue;
        } else {
            return Byte.valueOf(value);
        }
    }

    //......
}

• ParameterTool里头有data、defaultData、unrequestedParameters等属性，toMap方法返回的是data属性
• ParameterTool提供了fromPropertiesFile、fromArgs、fromSystemProperties、fromMap静态方法用于创建ParameterTool
• ParameterTool提供了get、getRequired、getInt、getLong、getFloat、getDouble、getBoolean、getShort、getByte等方法，每种类型的get均提供了一个支持defaultValue的方法

小结

• ParameterTool提供了fromPropertiesFile、fromArgs、fromSystemProperties、fromMap静态方法用于创建ParameterTool
• ParameterTool提供了get、getRequired、getInt、getLong、getFloat、getDouble、getBoolean、getShort、getByte等方法，每种类型的get均提供了一个支持defaultValue的方法
• ParameterTool继承了ExecutionConfig.GlobalJobParameters，其toMap方法返回的是data属性；使用env.getConfig().setGlobalJobParameters可以将ParameterTool的访问范围设置为global

doc

• Parsing command line arguments and passing them around in your Flink application