Commit Graph

17 Commits

Author SHA1 Message Date
Dennis Heimbigner
6abaab967b Fix some problems with PR https://github.com/Unidata/netcdf-c/pull/2492
re: PR https://github.com/Unidata/netcdf-c/pull/2492
re: Issue https://github.com/Unidata/netcdf-c/issues/2494

This PR fixes some problems with the pull request https://github.com/Unidata/netcdf-c/pull/2492 in response to Issue https://github.com/Unidata/netcdf-c/issues/2494.

* Found and fixed more scalar handling problems and add a test case for scalars.
* Cleanup nczarr_test/run_string.sh test
* Document *_nczarr_default_maxstrlen* and *_nczarr_maxstrlen*.

* Support both "Nan" and *Nan* as being floating point constants
  for attributes. It is unclear from the Zarr V2 spec if
  unquoted *Nan* is legal or not, but support for reading.
  Write the quoted versions when writing an attribute.  Similar
  for Infinity constants.
  So NCZarr supports the following constants for use in Attributes
    * *Nan*, "Nan", *-Nan*, "-Nan"
    * *Nanf*, "Nanf", *-Nanf*, "-Nanf"
    * *Infinity*, "Infinity", *-Infinity*, "-Infinity"
    * *Infinityf*, "Infinityf", *-Infinityf*, "-Infinityf"
2022-09-03 14:21:48 -06:00
Dennis Heimbigner
231ae96c4b Add support for Zarr string type to NCZarr
* re: https://github.com/Unidata/netcdf-c/pull/2278
* re: https://github.com/Unidata/netcdf-c/issues/2485
* re: https://github.com/Unidata/netcdf-c/issues/2474

This PR subsumes PR https://github.com/Unidata/netcdf-c/pull/2278.
Actually is a bit an omnibus covering several issues.

## PR https://github.com/Unidata/netcdf-c/pull/2278
Add support for the Zarr string type.
Zarr strings are restricted currently to be of fixed size.
The primary issue to be addressed is to provide a way for user to
specify the size of the fixed length strings. This is handled by providing
the following new attributes special:
1. **_nczarr_default_maxstrlen** —
This is an attribute of the root group. It specifies the default
maximum string length for string types. If not specified, then
it has the value of 64 characters.
2. **_nczarr_maxstrlen** —
This is a per-variable attribute. It specifies the maximum
string length for the string type associated with the variable.
If not specified, then it is assigned the value of
**_nczarr_default_maxstrlen**.

This PR also requires some hacking to handle the existing netcdf-c NC_CHAR
type, which does not exist in zarr. The goal was to choose numpy types for
both the netcdf-c NC_STRING type and the netcdf-c NC_CHAR type such that
if a pure zarr implementation read them, it would still work and an
NC_CHAR type would be handled by zarr as a string of length 1.

For writing variables and NCZarr attributes, the type mapping is as follows:
* "|S1" for NC_CHAR.
* ">S1" for NC_STRING && MAXSTRLEN==1
* ">Sn" for NC_STRING && MAXSTRLEN==n

Note that it is a bit of a hack to use endianness, but it should be ok since for
string/char, the endianness has no meaning.

For reading attributes with pure zarr (i.e. with no nczarr
atribute types defined), they will always be interpreted as of
type NC_CHAR.

## Issue: https://github.com/Unidata/netcdf-c/issues/2474
This PR partly fixes this issue because it provided more
comprehensive support for Zarr attributes that are JSON valued expressions.
This PR still does not address the problem in that issue where the
_ARRAY_DIMENSION attribute is incorrectly set. Than can only be
fixed by the creator of the datasets.

## Issue: https://github.com/Unidata/netcdf-c/issues/2485
This PR also fixes the scalar failure shown in this issue.
It generally cleans up scalar handling.
It also adds a note to the documentation describing that
NCZarr supports scalars while Zarr does not and also how
scalar interoperability is achieved.

## Misc. Other Changes
1. Convert the nczarr special attributes and keys to be all lower case. So "_NCZARR_ATTR" now used "_nczarr_attr. Support back compatibility for the upper case names.
2. Cleanup my too-clever-by-half handling of scalars in libnczarr.
2022-08-27 20:21:13 -06:00
Dennis Heimbigner
7b09290a3a Improve filter installation process to avoid use of an extra shell script
re: https://github.com/Unidata/netcdf-c/issues/2338
re: https://github.com/Unidata/netcdf-c/issues/2294

In issue https://github.com/Unidata/netcdf-c/issues/2338,
Ed Hartnett suggested a better way to install filters to a user
defined location -- for Automake, anyway.

This PR implements that suggestion. It turns out to be more
complicated than it appears, so there are fair number of changes;
mostly to shell scripts. Most of the change is in plugins/Makefile.am.

NOTE: this PR still does NOT address the use of HDF5_PLUGIN_PATH
as the default; this turns out to be complex when dealing with NCZarr.
So this will be addressed in a subsequent post 4.9.0 PR.

## Misc. Changes
1. Record the occurrences of incomplete codecs in libnczarr so that
   they can be included in _Codecs attribute correctly. This allows
   users to see what missing filters are referenced in the Zarr file.
   Primarily affects libnczarr/zfilter.[ch]. Also required creating a
   new no-effect filter: H5Zunknown.c.
2. Move the unknown filter test to a separate test file.
3. Incorporates PR https://github.com/Unidata/netcdf-c/pull/2343
2022-05-14 16:05:48 -06:00
Sean McBride
bb03191356 Fixed Clang -Wstrict-prototypes warnings 2022-03-01 23:21:24 -05:00
Dennis Heimbigner
446348ed18 Add complete bitgroom support to NCZarr
re: PR https://github.com/Unidata/netcdf-c/pull/2088
re: PR https://github.com/Unidata/netcdf-c/pull/2130
replaces: https://github.com/Unidata/netcdf-c/pull/2140

Changes:
* Add NCZarr-specific quantize functions to the dispatch table.
* Copy (modified) quantize code from libhdf5 to NCZarr
* Add quantize invocation to zvar.c
* Add support for _QuantizeBitgroomNumberOfSignificantDigits
and _QuantizeGranularBitgroomNumberOfSignificantDigits to ncgen.
* Modify nc_test4/tst_quantize.c to allow it to be used both for hdf5
  and for nczarr.
* Make dap4 properly handle quantize functions in dispatch table.
* Add quantize attribute support to ncgen.

Other changes:
* Caught and fixed some S3 problems
* Fixed some nczarr fillvalue problems.
* Fixed some nczarr cache problems.
* Cleanup some flaws in libdispatch/dinfermodel.c
* Allow byterange requests to S3 be readable by dinfermodel.c/check_file_type
* Remove the libnczarr ztracedispatch code (big change).
2022-01-24 15:22:24 -07:00
Dennis Heimbigner
11fe00ea05 Add filter support to NCZarr
Filter support has three goals:

1. Use the existing HDF5 filter implementations,
2. Allow filter metadata to be stored in the NumCodecs metadata format used by Zarr,
3. Allow filters to be used even when HDF5 is disabled

Detailed usage directions are define in docs/filters.md.

For now, the existing filter API is left in place. So filters
are defined using ''nc_def_var_filter'' using the HDF5 style
where the id and parameters are unsigned integers.

This is a big change since filters affect many parts of the code.

In the following, the terms "compressor" and "filter" and "codec" are generally
used synonomously.

### Filter-Related Changes:
* In order to support dynamic loading of shared filter libraries, a new library was added in the libncpoco directory; it helps to isolate dynamic loading across multiple platforms.
* Provide a json parsing library for use by plugins; this is created by merging libdispatch/ncjson.c with include/ncjson.h.
* Add a new _Codecs attribute to allow clients to see what codecs are being used; let ncdump -s print it out.
* Provide special headers to help support compilation of HDF5 filters when HDF5 is not enabled: netcdf_filter_hdf5_build.h and netcdf_filter_build.h.
* Add a number of new test to test the new nczarr filters.
* Let ncgen parse _Codecs attribute, although it is ignored.

### Plugin directory changes:
* Add support for the Blosc compressor; this is essential because it is the most common compressor used in Zarr datasets. This also necessitated adding a CMake FindBlosc.cmake file
* Add NCZarr support for the big-four filters provided by HDF5: shuffle, fletcher32, deflate (zlib), and szip
* Add a Codec defaulter (see docs/filters.md) for the big four filters.
* Make plugins work with windows by properly adding __declspec declaration.

### Misc. Non-Filter Changes
* Replace most uses of USE_NETCDF4 (deprecated) with USE_HDF5.
* Improve support for caching
* More fixes for path conversion code
* Fix misc. memory leaks
* Add new utility -- ncdump/ncpathcvt -- that does more or less the same thing as cygpath.
* Add a number of new test to test the non-filter fixes.
* Update the parsers
* Convert most instances of '#ifdef _MSC_VER' to '#ifdef _WIN32'
2021-09-02 17:04:26 -06:00
Dennis Heimbigner
d953899559 Move to Version 2 NCZarr Extended Meta-Data
re: https://github.com/zarr-developers/zarr-specs/issues/41

After discussions with the Zarr community, it was decided to
convert to a new representation of the NCZarr meta-data extensions: version 2.
These extensions store information necessary to mapping the Zarr data model
to the netcdf-4 data model.

The basic change is to remove the NCZarr specific objects: .nczarr, .nczgroup, .nczarray, and .nczattr.
The contents of these objects is moved into the corresponding existing Zarr objects as special keys. The mapping is as follows:

* ''.nczarr'' => ''/.zgroup/_NCZARR_SUPERBLOCK_''
* ''.nczgroup => ''.zgroup/_NCZARR_GROUP_''
* ''.nczarray => ''.zarray/_NCZARR_ARRAY_''
* ''.nczattr => ''.zattr/_NCZARR_ATTR_''

Backward compatibility is maintained by looking for the object ''/.nczarr''
and if found, then assuming that the dataset is in the older version 1 format.
This compatibility only supports reading of such version 1 datasets.

Documentation and test cases are also added.

Misc. Other Changes:
1. The json parsing code was added to the general library instead of nczarr only (ncjson.c, ncjson.h).
2. Improved support for different platform paths by allowing conversion
   to a single common path representation.
3. Add some new error codes.
4. Modify nccopy usage to mention the new chunking specification.
2021-07-17 16:55:30 -06:00
Dennis Heimbigner
74e7812d83 Improve error message when non-existent filter is encountered.
re: https://github.com/Unidata/netcdf-c/issues/1996

Improve the error message and location that is reported when reading a filter with a variable that uses a filter that is not available on the reading platform.

This requires checking the availability of the filter, recording it, and failing when any attempt is made to read or write that variable. A test case was added for this in tst_filter.sh. Also, LOG level 0 message is generated giving the variable and the filter id.

Note that by design if there is no attempt to read or write the variable, then no error is reported; this means that, for example, ncdump -h will list the filter even though it is not actually available. This is important for allowing a user to see the filter details.
2021-05-17 19:49:58 -06:00
Dennis Heimbigner
74b40fd788 Upgrade the nczarr code to match Zarr V2
Re: https://github.com/zarr-developers/zarr-python/pull/716

The Zarr version 2 spec has been extended to include the ability
to choose the dimension separator in chunk name keys. The legal
separators has been extended from {'.'} to {'.' '/'}.  So now it
is possible to use a key like "0/1/2/0" for chunk names.

This PR implements this for NCZarr. The V2 spec now says that
this separator can be set on a per-variable basis. For now, I
have chosen to allow this be set only globally by adding a key
named "ZARR.DIMENSION_SEPARATOR=<char>" in the
.daprc/.dodsrc/ncrc file. Currently, the only legal separator
characters are '.' (the default) and '/'. On writing, this key
will only be written if its value is different than the default.
This change caused problems because supporting a separator of '/'
is difficult to parse when keys/paths use '/' as the path separator.
A test case was added for this.

Additionally, make nczarr be enabled default by default. This required
some additional changes so that if zip and/or AWS S3 sdk are unavailable,
then they are disabled for NCZarr.

In addition the following unrelated changes were made.

1. Tested that pure-zarr mode could read an nczarr formatted store.
1. The .rc file handling now merges all known .rc files (.ncrc,.daprc, and .dodsrc) in that order and using those in HOME first, then in current directory. For duplicate entries, the later ones override the earlier ones. This change is to remove some of the conflicts inherent in the current .rc file load process. A set of test cases was also added.
1. Re-order tests in configure.ac and CMakeLists.txt so that if libcurl
   is not found then the other options that depend upon it properly
   are disabled.
1. I decided that xarray support should be enabled by default for pure
   zarr. In order to allow disabling, I added a new mode flag "noxarray".
1. Certain test in nczarr_test depend on use of .dodsrc. In order for these
   to work when testing in parallel, some inter-test dependencies needed to
   be added.
1. Improved authorization testing to use changes in thredds.ucar.edu
2021-04-24 19:48:15 -06:00
Dennis Heimbigner
2afbdbd18f Add support for the XArray Zarr _ARRAY_DIMENSIONS attribute
The XArray implementation that uses Zarr for storage
provides a mechanism to simulate named dimensions.
It does this by adding a per-variable attribute called
_ARRAY_DIMENSIONS. This attribute contains a list of names
to be matched against the shape values of the variable.
In effect a named dimension is created with the name
_ARRAY_DIMENSIONS(i) and length shape(i) for all i
in range 0..rank(variable).
Both read and write support is provided.

This XArray support is only invoked if the mode value
of "xarray" is defined. So for example, as in this URL.
````
https://s3.us-west-1.amazonaws.com/bucket/dataset#mode=nczarr,xarray,s3
````
Note that the "xarray" mode flag also implies mode flag "zarr", so the above
is equivalent to this URL.
````
https://s3.us-west-1.amazonaws.com/bucket/dataset#mode=nczarr,zarr,xarray,s3
````

The primary change to implement this was to unify the handling
of dimension references in libnczarr/zsync.

A test for this and other pure-zarr features was added as
nczarr_test/run_purezarr.sh

Other changes:
* Make sure distcheck leaves no files around.
* Change the special attribute flag DIMSCALEFLAG to HIDDENATTRFLAG
  to support the xarray attribute.
* Annotate the zmap implementations with feature flags such as
  WRITEONCE (for zip files).
2021-02-24 13:46:11 -07:00
Dennis Heimbigner
e7d5f24078 Add zip file support
The primary change is to support the use of a zip file as a
storage format. Simultaneously the .nz4 support is made obsolete

Use of zip requires the libzip support library, so a number of
changes to the build files (Makefile.am, CMakeLists.txt) are
necessary to locate and incorporate libzip.  The nczarr_tests
tests are also changed to add zip testing.

Other changes:
* Make sure distcheck leaves no files around.
* Add some functions to netcdf_aux to export some functions of libnetcdf.
* Add a new error NC_EFOUND as the complement of NC_EEMPTY.
* Add tracing support to nclog and use it in libnczarr.
* Modify the zmap interface to support the writeonce semantics of zip.
* Create a new s3util.c to support a variety of S3 auxilliary functions.
* EXTERNL'ize a number of functions so they can be used in s3util.
* Add support for the S3 ListObjects CommonPrefixes mechanism
  to improve search.
* Add experimental support for running nczarr X s3 tests against
  the actual Amazon S3 cloud.
2021-01-28 20:11:01 -07:00
Dennis Heimbigner
eb3d9eb0c9 Provide a Number of fixes/improvements to NCZarr
Primary changes:
* Add an improved cache system to speed up performance.
* Fix NCZarr to properly handle scalar variables.

Misc. Related Changes:
* Added unit tests for extendible hash and for the generic cache.
* Add config parameter to set size of the NCZarr cache.
* Add initial performance tests but leave them unused.
* Add CRC64 support.
* Move location of ncdumpchunks utility from /ncgen to /ncdump.
* Refactor auth support.

Misc. Unrelated Changes:
* More cleanup of the S3 support
* Add support for S3 authentication in .rc files: HTTP.S3.ACCESSID and HTTP.S3.SECRETKEY.
* Remove the hashkey from the struct OBJHDR since it is never used.
2020-11-19 17:01:04 -07:00
Dennis Heimbigner
aeb3ac2809 Mostly revert the filter code to reduce its complexity of use.
re: https://github.com/Unidata/netcdf-c/issues/1836

Revert the internal filter code to simplify it. From the user's
point of view, the only visible changes should be:

1. The functions that convert text to filter specs have had their signature reverted and have been moved to netcdf_aux.h
2. Some filter API functions now return NC_ENOFILTER when inquiry is made about some filter.

Internally,the dispatch table has been modified to get rid of the filter_actions
entry and associated complex structures. It has been replaced with
inq_var_filter_ids and inq_var_filter_info entries and the dispatch table
version has been bumped to 3. Corresponding NOOP and NOTNC4 functions
were added to libdispatch/dnotnc4.c. Also, the filter_action entries
in dispatch tables were replaced for all dispatch code bases (HDF5, DAP2,
etc). This should only impact UDF users.

In the process, it became clear that the form of the filters
field in NC_VAR_INFO_T was format dependent, so I converted it to
be of type void* and pushed its management into the various dispatch
code bases. Specifically libhdf5 and libnczarr now manage the filters
field in their own way.

The auxilliary functions for parsing textual filter specifications
were moved to netcdf_aux.h and were renamed to the following:
* ncaux_h5filterspec_parse
* ncaux_h5filterspec_parselist
* ncaux_h5filterspec_free
* ncaux_h5filter_fix8

Misc. Other Changes:

1. Document NUG/filters.md updated to reflect the changes above.
2. All the old data types (structs and enums)
   used by filter_actions actions were deleted.
   The exception is the NC_H5_Filterspec because it is needed
   by ncaux_h5filterspec_parselist.
3. Clientside filters were removed -- another enhancement
   for which no-one ever asked.
4. The ability to remove filters was itself removed.
5. Some functionality needed by nczarr was moved from libhdf5
   to libsrc4 e.g. nc4_find_default_chunksizes
6. All the filterx code was removed
7. ncfilter.h and nc4filter.c no longer used

Misc. Unrelated Changes:

1. The nczarr_test makefile clean was leaving some directories; so
   add clean-local to take care of them.
2020-09-27 12:43:46 -06:00
Ward Fisher
31dee0c4da
Revert "Revert "Fix nczarr-experimental: improve build support, disengage hdf5 vs netcdf4 flags, and find AWS libraries"" 2020-08-17 19:15:47 -06:00
Ward Fisher
16c27ca13f
Revert "Fix nczarr-experimental: improve build support, disengage hdf5 vs netcdf4 flags, and find AWS libraries" 2020-08-17 15:51:01 -06:00
Dennis Heimbigner
d85bb6fe20 The big change for this commit is complete the
disengagement of enable-netcdf4 from enable-hdf5.
That is, with the advent of nczarr, it is possible
to turn off hdf5 but still need netcdf-4 enabled
because nczarr uses libsrc4, but not libhdf5.
This change involves a bunch of things:
1. Modify configure.ac and CMakelist to make enable_hdf5
   control if hdf5 support is provided. For back compatibility,
   disable-netcdf4 is treated as disable-hdf5. But internally,
   netcdf4 support is controlled only by the enabling of formats
   that require it.
2. In support of #1, modify .travis.yml to use enable/disable-hdf5
   instead of enable/disable-netcdf4.
3. test_common.in is modified to track selected features,
   including enable-hdf5 and enable-s3-tests. This is used in
   selected tests that mix netcdf-3 and netcdf4 tests.
4. The conflation of USE_HDF5 and USE_NETCDF4 is common in
   code, tests, and build files, so all of those had to be weeded out.
5. It turns out that some of the NC4_dim functions really are HDF5 specific,
   but are not treated as such. So they are moved from nc4dim.c to
   hdf5dim.c or hdf5dispatch.c
6. Some generic functions in libhdf5 can be (and were) moved to libsrc4.
2020-08-12 15:42:50 -06:00
Dennis Heimbigner
59e04ae071 This PR adds EXPERIMENTAL support for accessing data in the
cloud using a variant of the Zarr protocol and storage
format. This enhancement is generically referred to as "NCZarr".

The data model supported by NCZarr is netcdf-4 minus the user-defined
types and the String type. In this sense it is similar to the CDF-5
data model.

More detailed information about enabling and using NCZarr is
described in the document NUG/nczarr.md and in a
[Unidata Developer's blog entry](https://www.unidata.ucar.edu/blogs/developer/en/entry/overview-of-zarr-support-in).

WARNING: this code has had limited testing, so do use this version
for production work. Also, performance improvements are ongoing.
Note especially the following platform matrix of successful tests:

Platform | Build System | S3 support
------------------------------------
Linux+gcc      | Automake     | yes
Linux+gcc      | CMake        | yes
Visual Studio  | CMake        | no

Additionally, and as a consequence of the addition of NCZarr,
major changes have been made to the Filter API. NOTE: NCZarr
does not yet support filters, but these changes are enablers for
that support in the future.  Note that it is possible
(probable?) that there will be some accidental reversions if the
changes here did not correctly mimic the existing filter testing.

In any case, previously filter ids and parameters were of type
unsigned int. In order to support the more general zarr filter
model, this was all converted to char*.  The old HDF5-specific,
unsigned int operations are still supported but they are
wrappers around the new, char* based nc_filterx_XXX functions.
This entailed at least the following changes:
1. Added the files libdispatch/dfilterx.c and include/ncfilter.h
2. Some filterx utilities have been moved to libdispatch/daux.c
3. A new entry, "filter_actions" was added to the NCDispatch table
   and the version bumped.
4. An overly complex set of structs was created to support funnelling
   all of the filterx operations thru a single dispatch
   "filter_actions" entry.
5. Move common code to from libhdf5 to libsrc4 so that it is accessible
   to nczarr.

Changes directly related to Zarr:
1. Modified CMakeList.txt and configure.ac to support both C and C++
   -- this is in support of S3 support via the awd-sdk libraries.
2. Define a size64_t type to support nczarr.
3. More reworking of libdispatch/dinfermodel.c to
   support zarr and to regularize the structure of the fragments
   section of a URL.

Changes not directly related to Zarr:
1. Make client-side filter registration be conditional, with default off.
2. Hack include/nc4internal.h to make some flags added by Ed be unique:
   e.g. NC_CREAT, NC_INDEF, etc.
3. cleanup include/nchttp.h and libdispatch/dhttp.c.
4. Misc. changes to support compiling under Visual Studio including:
   * Better testing under windows for dirent.h and opendir and closedir.
5. Misc. changes to the oc2 code to support various libcurl CURLOPT flags
   and to centralize error reporting.
6. By default, suppress the vlen tests that have unfixed memory leaks; add option to enable them.
7. Make part of the nc_test/test_byterange.sh test be contingent on remotetest.unidata.ucar.edu being accessible.

Changes Left TO-DO:
1. fix provenance code, it is too HDF5 specific.
2020-06-28 18:02:47 -06:00