omniparser: a native Golang ETL streaming parser and transform library for CSV, JSON, XML, EDI, text, etc.



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Omniparser is a native Golang ETL parser that ingests input data of various formats (CSV, txt, fixed length/width, XML, EDI/X12/EDIFACT, JSON, and custom formats) in streaming fashion and transforms data into desired JSON output based on a schema written in JSON.

Golang Version: 1.14





In the example folders above you will find pairs of input files and their schema files. Then in the .snapshots sub directory, you'll find their corresponding output files.

Online Playground

Use (may need to wait for a few seconds for heroku instance to wake up) for trying out schemas and inputs, yours or existing samples, to see how ingestion and transform work.


  • No good ETL transform/parser library exists in Golang.
  • Even looking into Java and other languages, choices aren't many and all have limitations:
    • Smooks is dead, plus its EDI parsing/transform is too heavyweight, needing code-gen.
    • BeanIO can't deal with EDI input.
    • Jolt can't deal with anything other than JSON input.
    • JSONata still only JSON -> JSON transform.
  • Many of the parsers/transforms don't support streaming read, loading entire input into memory - not acceptable in some situations.


  • Golang 1.14

Recent Major Feature Additions/Changes

  • Added Transform.RawRecord() for caller of omniparser to access the raw ingested record.
  • Deprecated custom_parse in favor of custom_func (custom_parse is still usable for back-compatibility, it is just removed from all public docs and samples).
  • Added NonValidatingReader EDI segment reader.
  • Added fixed-length file format support in omniv21 handler.
  • Added EDI file format support in omniv21 handler.
  • Major restructure/refactoring
    • Upgrade omni schema version to omni.2.1 due a number of incompatible schema changes:
      • 'result_type' -> 'type'
      • 'ignore_error_and_return_empty_str -> 'ignore_error'
      • 'keep_leading_trailing_space' -> 'no_trim'
    • Changed how we handle custom functions: previously we always use strings as in param type as well as result param type. Not anymore, all types are supported for custom function in and out params.
    • Changed the way how we package custom functions for extensions: previously we collect custom functions from all extensions and then pass all of them to the extension that is used; This feels weird, now changed to only the custom functions included in a particular extension are used in that extension.
    • Deprecated/removed most of the custom functions in favor of using 'javascript'.
    • A number of package renaming.
  • Added CSV file format support in omniv2 handler.
  • Introduced IDR node cache for allocation recycling.
  • Introduced IDR for in-memory data representation.
  • Added trie based high performance times.SmartParse.
  • Command line interface (one-off transform cmd or long-running http server mode).
  • javascript engine integration as a custom_func.
  • JSON stream parser.
  • Extensibility:
    • Ability to provide custom functions.
    • Ability to provide custom schema handler.
    • Ability to customize the built-in omniv2 schema handler's parsing code.
    • Ability to provide a new file format support to built-in omniv2 schema handler.


  • [feature] parsing multiple nested records under fixed-length parser

    [feature] parsing multiple nested records under fixed-length parser


    Are there plans or some documentation around how to support parsing of multiple nested objects in fixed-length parser?

    i.e. format like this one, that have repeating and nested elements like NWR under GRHNWR and also SPU SPT, SWT, SWR under NWR records.

    HDRPB123456789SAMPLE MEDIA MUSIC                        01.1000000003200123412340713
    NWR0000000000000000Song 1 - 1 Pub1/ 0 Wrt                                        00000000100001T000000000100000000            POP000000Y      ORI         TM (BULK)
    SPU000000000000000101Pub10    Publisher 10                         E 00000000000700000010              010012000340120009901200 N                                          OG
    SPT0000000000000002RMM            002090041800000I2136N001
    NWR0000000100000000Song 2 - 1 Pub2/ 0 Wrt // 1 SPU-AM                            00000000100002T000000000200000000            POP000000Y      ORI         TM (BULK)
    SPU000000010000000101Pub20    Publisher 20                         E 00000000000700000020              010012000340120009901200 N                                          OG
    SPU000000010000000201RMM      SAMPLE MEDIA MUSIC                   AM000000000005470437533745610       010000000340000009900000 N                            5594837       PG
    SPT0000000100000003RMM            002090041800000I2136N001
    NWR0000000300000000Song 4 - 1 Pub1/ 1 Wrt1                                       00000000100004T000000000400000000            POP000000Y      ORI         TM (BULK)
    SPU000000030000000101Pub10    Publisher 10                         E 00000000000700000010              010012000340120009901200 N                                          OG
    SPT0000000300000002RMM            002090041800000I2136N001
    SWR0000000300000003Wrt100   Writer 100                                   Controlled                     CA00000000000700000100010040000340400009904000 N
    SWT0000000300000004Wrt100   004180000000000I2136N001
    NWR0000000500000000Song 5 - 2 Pub1,2 / 2 Wrt - 1 new 1 old                       00000000100005T000000000500000000            POP000000Y      ORI         TM (BULK)
    SPU000000050000000101Pub10    Publisher 10                         E 00000000000700000010              010010000340100009901000 N                                          OG
    SPT0000000500000002RMM            002090041800000I2136N001
    SPU000000050000000301Pub50    Publisher 50                         E 00000000000700000050              010010000340100009901000 N                                          OG
    SPT0000000500000004RMM            002090041800000I2136N001
    SWR0000000500000005Wrt100   Writer 100                                   Controlled                     CA00000000000700000100010030000340300009903000 N
    SWT0000000500000006Wrt100   004180000000000I2136N001
    SWR0000000500000007Wrt500   Writer 500                                   Controlled                     CA00000000000700000500010030000340300009903000 N
    SWT0000000500000008Wrt500   004180000000000I2136N001
    opened by cavke 37
  • [EDI] Huge memory leak when parsing ~20MB EDI file

    [EDI] Huge memory leak when parsing ~20MB EDI file

    Hi, we found a huge memory leak on parsing the EDI file with a size of over 20Mb

    • EDI is a sample INVOIC type with millions of LIN items.
    • attaching SVG of export --memprofile of benchmark,
    • it allocates over 5GB memory for the single ~23MB EDI file

    is there any alternative to rather than calling ingester.Parse() for the large files?

    opened by jurabek 10
  • CSV Example

    CSV Example

    I am following the CSV Example. The schema includes a header of "header": "^DATE|HIGH TEMP C|LOW TEMP F|WIND DIR|WIND SPEED KMH|NOTE|LAT|LONG|UV INDEX$".

    In package csv, decl.go's RowsBased (called from reader.go ReadAndMatch) function says if r.Header == nil then it's rows based but the line above makes the header not nil? So now it thinks my CSV is Header and Footer based.

    What am I missing?

    opened by bjordan2010 8
  • Return unique hash for input

    Return unique hash for input

    So i'm busy ingesting shipments, they arrive as either csv, json, xml or edi

    The interface I'm working should take an array of shipments, divide that into individual shipments, hash those and store the original input for success/audit/retry/failure tracking reasons. This would make it easier to ingest 99/100 shipments and retry (after localizing and fixing the issue) that one shipment that's invalid for whatever reason.

    In order to decide whether something has been ingested correctly I thought a solution could be hashing it 'unit' of input and storing the original input somewhere as well

    Quite easy for csv

    Weird python-and-bash-esque psuedocode:

    for line in csv:
      process(line) && hash(line) && gzip(line) -> store result, hash, line in db

    It becomes less so for json and xml, even marshal and unmarshal is not 100% identical to the input

    Even worse is EDI

    So, even though I liked the idea of storing the original it quickly becomse cumbersome. A decent alternative is is hashing and storing the output of transform.Read()

    But that comes with several issues

    • I can change the output and thus the hash using the schema (not really an issue)
    • its not original (but it is more consistent (all json)), so kind of bug/feature
    • I don't see what I haven't told omniparser to see, so new fields that might have been added

    None of these are a major issue, but part of hashing a new representation of the input, not the input itself

    I was wondering how hard would it be to hash the input of whatever generates the output would be? So: hash, data, err := transform.Read

    Is your internal data stable enough? That you could say 'for loop' the IDR input through the sha256 encoder (it supports streaming) and return a stable/unchanging hash?

    As in, in theory ["a", "b", "c"] should return the same hash for a, b and c regardless of ordering

    Also, I imagine being able to verify whether a file has been fully processed is interesting for more than one usecase

    opened by DGollings 8
  • [EDI] Handle segment compression

    [EDI] Handle segment compression

    Disclaimer: I only assume this is segment compression, as defined in the manual

    7.1 Exclusion of segments Conditional segments containing no data shall be omitted (including their segment tags).

    This is what I encountered in the schema, basically a mandatory/conditional sandwich.

    SG25 R 99
    43 NAD M 1
    44 LOC Orts 9 O
    SG25 R 99
    45 NAD M 1
    46 LOC O 9
        SG29 C 9
        47 RFF M 1
    SG25 O 99
    48 NAD M 1
    SG25 D 99
    49 NAD M 1
    SG25 D 99
    50 NAD M 1
    SG25 O 99
    51 NAD M 1
    SG25 M 99
    52 NAD M 1
        SG29 C 9
        53 RFF M 1
    SG25 D 99
    54 NAD M 1
    SG25 R 99
    55 NAD M 1
    SG25 R 99
    56 NAD M 1
        SG26 C 9
        57 CTA O 1
        58 COM O 9

    None of the conditional statements were present in the data I was trying to parse, ended up fixing it using:

                        "name": "SG25-SENDER",
                        "min": 1,
                        "type": "segment_group",
                        "child_segments": [
                            "name": "NAD",
                            "min": 1,
                            "elements": [
                              { "name": "cityName", "index": 1 },
                              { "name": "provinceCode", "index": 2 },
                              { "name": "postalCode", "index": 3 },
                              { "name": "countryCode", "index": 4 }
                          { "name": "LOC", "min": 0 }
                        "name": "SG25-RECEIVER",
                        "min": 1,
                        "type": "segment_group",
                        "child_segments": [
                          { "name": "NAD", "min": 1 },
                          { "name": "LOC", "min": 0 },
                            "name": "SG29",
                            "min": 0,
                            "type": "segment_group",
                            "child_segments": [{ "name": "RFF", "min": 1 }]
                        "name": "SG25-OTHERS",
                        "min": 0,
                        "max": 99,
                        "type": "segment_group",
                        "child_segments": [
                            "name": "SG26",
                            "min": 0,
                            "type": "segment_group",
                            "child_segments": [
                              { "name": "CTA", "min": 0 },
                              { "name": "COM", "min": 0, "max": -1 }
                          { "name": "NAD", "min": 0, "max": -1 },
                          { "name": "LOC", "min": 0 },
                            "name": "SG29",
                            "min": 0,
                            "type": "segment_group",
                            "child_segments": [{ "name": "RFF", "min": 1 }]

    The message I'm trying to parse

    NAD+CZ+46388514++Foo A/S+Foo 2+Foo++Foo+DK'
    NAD+CN+46448510++NL01001 Foo Foo Foo:Foo+Foo 6+Foo++Foo+NL'
    CTA+CN+AS:NL01001 Foo'
    [email protected]:EM'

    Which basically means, grab the two explicit ones (luckily at top), and do as you wish with the others in whatever order you encounter them. I'm not sure how I would have handled it if I did care about NAD+LP

    Also had to use min/max 1 instead of the specified 99, as it only considers NAD, not NAD+FIRSTVALUE when 'collapsing' similar but not same segments.

    Basically, the EDI specification has a lot of implicitness which I think is quite hard to easily parse.

    opened by DGollings 6
  • supports a

    supports a "segment_prefix" in the edi parser file declaration

    I'm working with a non-standard EDI format that includes a segment prefix. For example, a message might be:


    where every segment begins with a pipe. I thought that I could get around this by making the segment delimiter include the next pipe (ie |\n|), but this doesn't catch the very first pipe.

    I propose including a new (optional) "segment_prefix" field in the file_declaration to catch segment prefixes.

    opened by samolds 5
  • Edi parsing failing, with error segment needs min occur 1, but only got 0

    Edi parsing failing, with error segment needs min occur 1, but only got 0

    opened by rohanbr 5
  • [EDI] Handle (or ignore?) line endings

    [EDI] Handle (or ignore?) line endings

    Consider the header

    UNA:+.? '

    This wouldn't be

        "component_delimiter": ":",
        "element_delimiter": "+",
        "segment_delimiter": "'",
        "release_character": "?",

    But instead is

        "component_delimiter": ":",
        "element_delimiter": "+",
        "segment_delimiter": "'\n", <--
        "release_character": "?",

    If the file you're trying to read contains line endings. Maybe the safest/easiest option would be removing all line endings?

    opened by DGollings 5
  • Error in go get install latest version

    Error in go get install latest version


    I am getting following error while installing the latest version v1.0.2 of omniparser

    extensions/omniv21/fileformat/flatfile/fixedlength/.snapshots/TestReadAndMatchRowsBasedEnvelope-non-empty_buf;_no_read;_match;_create_IDR: malformed file path "extensions/omniv21/fileformat/flatfile/fixedlength/.snapshots/TestReadAndMatchRowsBasedEnvelope-non-empty_buf;_no_read;_match;_create_IDR": invalid char ';'

    probably accidental typo in file name is checked in

    opened by deokapil 4
  • JSON/XML to EDI conversion

    JSON/XML to EDI conversion

    Could you please clarify if JSON / XML data can be converted to EDI EDIFACT data? If feasible, could you please provide a small example? Thank you in advance.

    opened by sankethpb 4
  • Ignore blank rows CSV

    Ignore blank rows CSV


    encountered a csv (converted from xlsx) where one line was all blank (,,,,,,)

    Errored on 'cannot convert "" to int'

    Now I fixed it at the source, but in general, it might be useful to add the option 'ignore blank row' or be able to set a default (like you can in EDI) for empty values? Especially when casting? (in this case, setting '' to 0)

    opened by DGollings 4
  • Is it possible to chain javascript custom functions?

    Is it possible to chain javascript custom functions?

    Hello. I was wondering if Is it possible to chain javascript or javascript_with_context custom functions? I haven't been able to get the right syntax if so. If I swap the value for name below from concat to javascript and add javascript args I get either invalid number of args or ILLEGAL javascript or cannot specify 'xpath' or 'xpath_dynamic' on both [sic: field and template].

    I was able to figure out how to chain javascript and built in functions below. If not is the only solution to attempt to code both operations in a single javascript function?

    "left_pad_with_zero_for_7_and_append_dash_old": {
    	"custom_func": {
    		"name": "concat",
    		"args": [
    				"custom_func": {
    					"name": "javascript",
    					"args": [
    							"const": "if (x.length < 7) { i=0; b=7-x.length; for (i=0; i < b; i++) { x = '0' + x}} else { x };"
    							"const": "x"
    							"xpath": "."
    				"const": "-old"
    opened by bjordan2010 1
  • Converting JSON to EDI X12

    Converting JSON to EDI X12

    Hi all, first of all I would say this tool is great, thanks for all that you have done. I just have a simple question if there is a way to convert json to EDI (X12), or whether something like that is on a roadmap somewhere?

    opened by djorgji 6
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