Timestamp format filter plugin for Embulk

A filter plugin for Embulk to change timestamp format

Configuration

• columns: columns to retain (array of hash)
  • name: name of column (required)
  • type: type to cast (string, timestamp, long (unixtimestamp), double (unixtimestamp), default is string)
  • from_format: specify the format of the input string (array of strings, default is default_from_timestamp_format)
  • from_timezone: specify the timezone of the input string (string, default is default_from_timezone)
  • to_format: specify the format of the output string (string, default is default_to_timestamp_format)
  • to_timezone: specify the timezone of the output string (string, default is default_to_timezone)
  • from_unit: specify the time unit of the input unixtimestamp (string, default is default_from_timestamp_unit)
  • to_unit: specify the time unit of the output unixtimestamp (string, default is default_to_timestamp_unit)
• default_from_timestamp_format: default timestamp format for the input string (array of strings, default is ["%Y-%m-%d %H:%M:%S.%N %z"])
• default_from_timezone: default timezone for the input string (string, default is UTC)
• default_to_timestamp_format: default timestamp format for the output string (string, default is %Y-%m-%d %H:%M:%S.%N %z)
• default_to_timezone: default timezone for the output string (string, default is UTC)
• default_from_timetamp_unit: default time unit such as second, ms, us, ns for the input unixtimestamp (string, default is second)
• default_to_timetamp_unit: default time unit such as second, ms, us, ns for the output unixtimestamp (string, default is second)
• stop_on_invalid_record: stop bulk load transaction if a invalid record is found (boolean, default is false)

Example

Say example.jsonl is as follows (this is a typical format which Exporting BigQuery table outputs):

{"timestamp":"2015-07-12 15:00:00 UTC","nested":{"timestamp":"2015-07-12 15:00:00 UTC"}}
{"timestamp":"2015-07-12 15:00:00.1 UTC","nested":{"timestamp":"2015-07-12 15:00:00.1 UTC"}}

in:
  type: file
  path_prefix: example/example.jsonl
  parser:
    type: jsonl
    columns:
    - {name: timestamp, type: string}
    - {name: nested, type: json}
filters:
  - type: timestamp_format
    default_to_timezone: "Asia/Tokyo"
    default_to_timestamp_format: "%Y-%m-%d %H:%M:%S.%N"
    columns:
      - {name: timestamp, from_format: ["%Y-%m-%d %H:%M:%S.%N %z", "%Y-%m-%d %H:%M:%S %z"]}
      - {name: $.nested.timestamp, from_format: ["%Y-%m-%d %H:%M:%S.%N %z", "%Y-%m-%d %H:%M:%S %z"]}
  type: stdout

Output will be as:

{"timestamp":"2015-07-13 00:00:00.0","nested":{"timestamp":"2015-07-13 00:00:00.0}}
{"timestamp":"2015-07-13 00:00:00.1","nested":{"timestamp":"2015-07-13 00:00:00.1}}

See ./example for more examples.

Timestamp Parser/Formatter Performance Issue

Embulk's timestamp parser/formatter originally uses jruby implementation, but it is slow. To improve performance, this plugin also supports Java's SimpleDateFormat format as:

in:
  type: file
  path_prefix: example/example.jsonl
  parser:
    type: jsonl
    columns:
    - {name: timestamp, type: string}
    - {name: nested, type: json}
filters:
  - type: timestamp_format
    default_from_timezone: "Asia/Taipei"
    default_from_timestamp_format: ["yyyy-MM-dd HH:mm:ss.SSS z", "yyyy-MM-dd HH:mm:ss z", "yyyy-MM-dd HH:mm:ss"]
    default_to_timezone: "Asia/Taipei"
    default_to_timestamp_format: "yyyy-MM-dd HH:mm:ss.SSS Z"
    columns:
      - {name: timestamp}
      - {name: $.nested.timestamp}
out:
  type: stdout

If format strings contain %, jruby parser/formatter is used. Otherwirse, java parser/formatter is used

COMPARISON:

Benchmark test sets are available at ./bench. In my environment (Mac Book Pro), for 1000000 timestamps:

• jruby parser/formatter: 65.06s
• java parser/formatter: 1.3s

NOTICE:

• JRuby parser has micro second resolution, but Java parser (SimpleDateFormat) has only milli second resolution
• S requires three digits always. For example, yyyy-MM-dd HH:mm::ss.S for 2015-12-17 01:02:03.1 gives 001 milli seconds wrongly, but it is the specification of SimpleDateFormat.

ToDo

• Write test

Development

Run example:

$ ./gradlew classpath
$ embulk preview -I lib example/example.yml

Run test:

$ ./gradlew test

Run checkstyle:

$ ./gradlew check

Release gem:

$ ./gradlew gemPush