Source - TabularWriteableSourceBuilder

Check the source outputs for validity and identify any errors. When the if predicate returns true the source will be terminated with an error message and output data will not be produced.

Parameters

Name	Type	Description
`config`	`Object`	the error message and predicate
`config.if`	(`value`: `Variable`, `inputs`: `Inputs`) => `EastFunction`	If true an error will be created
`config.message`	`string` \| (`value`: `Variable`, `inputs`: `Inputs`) => `EastFunction`	The message in the case that an error is created

Returns

a new

Example

 const source = new SourceBuilder("FloatSource")
     .input({ name: "max", stream: max_stream })
     .writeable(FloatType)
     .error({
         if: (value, { max }) => Greater(value, max),
         message: (value) => StringJoin`The value ${value} exceeds maximum`
     })

Inherited from

AbstractSourceBuilder.error

errorEvery

▸ errorEvery(config):

Add an assertion on every row of the source output to identify errors. For each row when the if predicate returns true the source will be terminated with an error message and output data will not be produced.

Parameters

Name	Type	Description
`config`	`Object`	the error message and predicate
`config.if`	(`fields`: `TypeToFields`, `key`: `Variable`, `inputs`: `Inputs`) => `EastFunction`	If true an error will be created
`config.message`	`string` \| (`fields`: `TypeToFields`, `key`: `Variable`, `inputs`: `Inputs`) => `EastFunction`	The message in the case that an error is created

Returns

a new

Example

 const maximumValue = Stream("MaximumValue", FloatType)

 const tableSource = new SourceBuilder("TableSource")
     .input({ name: "max", stream: other })
     .writeable(DictType(StringType, StructType({ id: IntegerType, value: FloatType, })))
     .errorEvery({
         if: ({ value }, { max }) => Greater(value, max),
         message: ({ id }) => StringJoin`The value for row with id ${id} exceeds maximum`
     })

input

▸ input(config):

TabularWriteableSourceBuilder<T, Inputs & { [K in string]: Variable }>

Add a stream as input to the SourceBuilder, which can be used in expressions to configure how the

Source will access the data (such as a URL or password), the output data, or any data assertions (preconditions and postconditions).

Type parameters

Name	Type
`Name`	extends `string`
`S`	extends `EastType`

Parameters

Name	Type	Description
`config`	`Object`	the configuration for the `input`
`config.name`	`Name` extends `"input"` \| keyof `Inputs` ? `never` : `Name`	the name to give the input Variable
`config.stream`	`Stream`	the input stream (the stream and associated preconditions)

Returns

TabularWriteableSourceBuilder<T, Inputs & { [K in string]: Variable }>

a new

Example

 const other = Stream("Other", FloatType)
 const source = new SourceBuilder("Source")
     .input({ name: "other", stream: other })
     .clock({ cron: "0 * * * *" })
     .toSource()

log

▸ log(config):

Produce log messages based on the source outputs and inputs. When the if predicate returns true source will register a warning with a message, but will proceed to proceed to produce output data.

Parameters

Name	Type	Description
`config`	`Object`	the log message and optional predicate
`config.if?`	(`value`: `Variable`, `inputs`: `Inputs`) => `EastFunction`	If true a log message will be produced (optional)
`config.message`	`string` \| (`value`: `Variable`, `inputs`: `Inputs`) => `EastFunction`	The message in the case that a warning is created

Returns

a new

Example

 const source = new SourceBuilder("FloatSource")
     .input({ name: "max", stream: max_stream })
     .writeable(FloatType)
     .log({
         if: (value, { max }) => Greater(value, max),
         message: (value) => StringJoin`The value ${value} exceeds maximum`
     })

Inherited from

AbstractSourceBuilder.log

logEvery

▸ logEvery(config):

Produce a long message for every row of the table. For each row when the if predicate returns true the source will register a log message and proceed to proceed to produce output data.

Parameters

Name	Type	Description
`config`	`Object`	the log message and optional predicate
`config.if?`	(`fields`: `TypeToFields`, `key`: `Variable`, `inputs`: `Inputs`) => `EastFunction`	If true a log message will be produced
`config.message`	`string` \| (`fields`: `TypeToFields`, `key`: `Variable`, `inputs`: `Inputs`) => `EastFunction`	The message in the case that a warning is create

Returns

a new

Example

 const maximumValue = Stream("MaximumValue", FloatType)

 const tableSource = new SourceBuilder("TableSource")
     .input({ name: "max", stream: other })
     .writeable(DictType(StringType, StructType({ id: IntegerType, value: FloatType, })))
     .logEvery({
         if: ({ value }, { max }) => Greater(value, max),
         message: ({ id }) => StringJoin`The value for row with id ${id} exceeds maximum`
     })

outputStream

▸ outputStream():

Return the

Stream containing the output of the data source.

Returns

Example

// Create a datastream where a password can be written by end-user at runtime.
const hourly = new SourceBuilder("DatabasePassword")
    .writeable(StringType)
    .outputStream()

Overrides

AbstractSourceBuilder.outputStream

toTemplate

▸ toTemplate():

Template

Return a

Template fragment containing the Streams and TaskDescriptions built by this builder.

Returns

Template

Example

// Create a datastream which is updated to the current time at the beginning of every hour
export default new SourceBuilder("Hourly")
    .clock({ cron: "0 * * * *" })
    .toTemplate()

Overrides

AbstractSourceBuilder.toTemplate

warn

▸ warn(config):

Check the source outputs for validity and produce warnings as necessary. When the if predicate returns true the source will register a warning with a message, but will proceed to proceed to produce output data.

Parameters

Name	Type	Description
`config`	`Object`	the warning message and predicate
`config.if`	(`value`: `Variable`, `inputs`: `Inputs`) => `EastFunction`	If true a warning will be produced
`config.message`	`string` \| (`value`: `Variable`, `inputs`: `Inputs`) => `EastFunction`	The message in the case that a warning is created

Returns

a new

Example

 const source = new SourceBuilder("FloatSource")
     .input({ name: "max", stream: max_stream })
     .writeable(FloatType)
     .warn({
         if: (value, { max }) => Greater(value, max),
         message: (value) => StringJoin`The value ${value} exceeds maximum`
     })

Inherited from

AbstractSourceBuilder.warn

warnEvery

▸ warnEvery(config):

Add an warning on every row of the source output to identify errors. For each row when the if predicate returns true the source will register a warning with a message, but will proceed to proceed to produce output data.

Parameters

Name	Type	Description
`config`	`Object`	the warning message and predicate
`config.if`	(`fields`: `TypeToFields`, `key`: `Variable`, `inputs`: `Inputs`) => `EastFunction`	If true a warning will be produced
`config.message`	`string` \| (`fields`: `TypeToFields`, `key`: `Variable`, `inputs`: `Inputs`) => `EastFunction`	The message in the case that a warning is create

Returns

a new

Example

 const maximumValue = Stream("MaximumValue", FloatType)

 const tableSource = new SourceBuilder("TableSource")
     .input({ name: "max", stream: other })
     .writeable(DictType(StringType, StructType({ id: IntegerType, value: FloatType, })))
     .warnEvery({
         if: ({ value }, { max }) => Greater(value, max),
         message: ({ id }) => StringJoin`The value for row with id ${id} exceeds maximum`
     })

writeableStream

▸ writeableStream():

Return the

Stream containing the stream end-users can write to.

Returns