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/*
* Copyright 2015 TouchType Ltd
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.databricks.spark.redshift
import com.amazonaws.auth.{AWSCredentials, BasicSessionCredentials}
/**
* All user-specifiable parameters for spark-redshift, along with their validation rules and
* defaults.
*/
private[redshift] object Parameters {
val DEFAULT_PARAMETERS: Map[String, String] = Map(
// Notes:
// * tempdir, dbtable and url have no default and they *must* be provided
// * sortkeyspec has no default, but is optional
// * distkey has no default, but is optional unless using diststyle KEY
// * jdbcdriver has no default, but is optional
"overwrite" -> "false",
"diststyle" -> "EVEN",
"usestagingtable" -> "true",
"preactions" -> ";",
"postactions" -> ";"
)
/**
* Merge user parameters with the defaults, preferring user parameters if specified
*/
def mergeParameters(userParameters: Map[String, String]): MergedParameters = {
if (!userParameters.contains("tempdir")) {
throw new IllegalArgumentException("'tempdir' is required for all Redshift loads and saves")
}
if (!userParameters.contains("url")) {
throw new IllegalArgumentException("A JDBC URL must be provided with 'url' parameter")
}
if (!userParameters.contains("dbtable") && !userParameters.contains("query")) {
throw new IllegalArgumentException(
"You must specify a Redshift table name with the 'dbtable' parameter or a query with the " +
"'query' parameter.")
}
if (userParameters.contains("dbtable") && userParameters.contains("query")) {
throw new IllegalArgumentException(
"You cannot specify both the 'dbtable' and 'query' parameters at the same time.")
}
val credsInURL = userParameters.get("url")
.filter(url => url.contains("user=") || url.contains("password="))
if (userParameters.contains("user") || userParameters.contains("password")) {
if (credsInURL.isDefined) {
throw new IllegalArgumentException(
"You cannot specify credentials in both the URL and as user/password options")
}
} else if (credsInURL.isEmpty) {
throw new IllegalArgumentException(
"You must specify credentials in either the URL or as user/password options")
}
MergedParameters(DEFAULT_PARAMETERS ++ userParameters)
}
/**
* Adds validators and accessors to string map
*/
case class MergedParameters(parameters: Map[String, String]) {
/**
* A root directory to be used for intermediate data exchange, expected to be on S3, or
* somewhere that can be written to and read from by Redshift. Make sure that AWS credentials
* are available for S3.
*/
def rootTempDir: String = parameters("tempdir")
/**
* Creates a per-query subdirectory in the [[rootTempDir]], with a random UUID.
*/
def createPerQueryTempDir(): String = Utils.makeTempPath(rootTempDir)
/**
* The Redshift table to be used as the target when loading or writing data.
*/
def table: Option[TableName] = parameters.get("dbtable").map(_.trim).flatMap { dbtable =>
// We technically allow queries to be passed using `dbtable` as long as they are wrapped
// in parentheses. Valid SQL identifiers may contain parentheses but cannot begin with them,
// so there is no ambiguity in ignoring subqeries here and leaving their handling up to
// the `query` function defined below.
if (dbtable.startsWith("(") && dbtable.endsWith(")")) {
None
} else {
Some(TableName.parseFromEscaped(dbtable))
}
}
/**
* The Redshift query to be used as the target when loading data.
*/
def query: Option[String] = parameters.get("query").orElse {
parameters.get("dbtable")
.map(_.trim)
.filter(t => t.startsWith("(") && t.endsWith(")"))
.map(t => t.drop(1).dropRight(1))
}
/**
* User and password to be used to authenticate to Redshift
*/
def credentials: Option[(String, String)] = {
for (
user <- parameters.get("user");
password <- parameters.get("password")
) yield (user, password)
}
/**
* A JDBC URL, of the format:
*
* jdbc:subprotocol://host:port/database?user=username&password=password
*
* Where:
* - subprotocol can be postgresql or redshift, depending on which JDBC driver you have loaded.
* Note however that one Redshift-compatible driver must be on the classpath and match this
* URL.
* - host and port should point to the Redshift master node, so security groups and/or VPC will
* need to be configured to allow access from the Spark driver
* - database identifies a Redshift database name
* - user and password are credentials to access the database, which must be embedded in this
* URL for JDBC
*/
def jdbcUrl: String = parameters("url")
/**
* The JDBC driver class name. This is used to make sure the driver is registered before
* connecting over JDBC.
*/
def jdbcDriver: Option[String] = parameters.get("jdbcdriver")
/**
* Set the Redshift table distribution style, which can be one of: EVEN, KEY or ALL. If you set
* it to KEY, you'll also need to use the distkey parameter to set the distribution key.
*
* Default is EVEN.
*/
def distStyle: Option[String] = parameters.get("diststyle")
/**
* The name of a column in the table to use as the distribution key when using DISTSTYLE KEY.
* Not set by default, as default DISTSTYLE is EVEN.
*/
def distKey: Option[String] = parameters.get("distkey")
/**
* A full Redshift SORTKEY specification. For full information, see latest Redshift docs:
* http://docs.aws.amazon.com/redshift/latest/dg/r_CREATE_TABLE_NEW.html
*
* Examples:
* SORTKEY (my_sort_column)
* COMPOUND SORTKEY (sort_col1, sort_col2)
* INTERLEAVED SORTKEY (sort_col1, sort_col2)
*
* Not set by default - table will be unsorted.
*
* Note: appending data to a table with a sort key only makes sense if you know that the data
* being added will be after the data already in the table according to the sort order. Redshift
* does not support random inserts according to sort order, so performance will degrade if you
* try this.
*/
def sortKeySpec: Option[String] = parameters.get("sortkeyspec")
/**
* DEPRECATED: see PR #157.
*
* When true, data is always loaded into a new temporary table when performing an overwrite.
* This is to ensure that the whole load process succeeds before dropping any data from
* Redshift, which can be useful if, in the event of failures, stale data is better than no data
* for your systems.
*
* Defaults to true.
*/
def useStagingTable: Boolean = parameters("usestagingtable").toBoolean
/**
* Extra options to append to the Redshift COPY command (e.g. "MAXERROR 100").
*/
def extraCopyOptions: String = parameters.get("extracopyoptions").getOrElse("")
/**
* Description of the table, set using the SQL COMMENT command.
*/
def description: Option[String] = parameters.get("description")
/**
* List of semi-colon separated SQL statements to run before write operations.
* This can be useful for running DELETE operations to clean up data
*
* If the action string contains %s, the table name will be substituted in, in case a staging
* table is being used.
*
* Defaults to empty.
*/
def preActions: Array[String] = parameters("preactions").split(";")
/**
* List of semi-colon separated SQL statements to run after successful write operations.
* This can be useful for running GRANT operations to make your new tables readable to other
* users and groups.
*
* If the action string contains %s, the table name will be substituted in, in case a staging
* table is being used.
*
* Defaults to empty.
*/
def postActions: Array[String] = parameters("postactions").split(";")
/**
* The IAM role to assume for Redshift COPY/UNLOAD operations. This takes precedence over
* other forms of authentication.
*/
def iamRole: Option[String] = parameters.get("aws_iam_role")
/**
* Temporary AWS credentials which are passed to Redshift. These only need to be supplied by
* the user when Hadoop is configured to authenticate to S3 via IAM roles assigned to EC2
* instances.
*/
def temporaryAWSCredentials: Option[AWSCredentials] = {
for (
accessKey <- parameters.get("temporary_aws_access_key_id");
secretAccessKey <- parameters.get("temporary_aws_secret_access_key");
sessionToken <- parameters.get("temporary_aws_session_token")
) yield new BasicSessionCredentials(accessKey, secretAccessKey, sessionToken)
}
}
}
