## S3 Related Fixes
* Add comprehensive support for specifying AWS profiles to provide access credentials.
* Parse the files "~/.aws/config" and "~/.aws/credentials to provide credentials for the HDF5 ROS3 driver and to locate default region.
* Add a function to obtain the currently active S3 credentials. The search rules are defined in docs/nczarr.md.
* Provide documentation for the new features.
* Modify the struct NCauth (in include/ncauth.h) to replace specific S3 credentials with a profile name.
* Add a unit test to test the operation of profile and credentials management.
* Add support for URLS of the form "s3://<bucket>/<key>"; this requires obtaining a default region.
* Allows the specification of profile and/or region in a URL of the form "#mode=nczarr,...&aws.region=...&aws.profile=..."
## Misc. Fixes
* Move the ezxml code to libdispatch so that it can be used both by DAP4 and nczarr.
* Modify nclist to provide a deep clone operation.
* Modify ncuri to provide a deep clone operation.
* Modify the .rc file format to allow the specification of a path to be tested when looking for an entry in the .rc file.
* Ensure that the NC_rcload function is called.
* Modify nchttp to support setting request headers.
GCC warns if the length parameter to `strncpy` is computed from the
source since it is actually the destination that is relevant here. Since
these allocations are all made with the right amount, other string
functions may be used instead.
re: https://github.com/Unidata/netcdf-c/issues/1827
The issue is partly resolved by this PR. The proximate problem appears to be that the semantics of mkstemp in **nix is different than the semantics of _mktemp_s in Windows. I had thought they were the same but that is incorrect. The _mktemp_s function will only produce 26 different files and so the netcdf temp file code will fail after about that many iterations.
So, to solve this, I created my own version of mkstemp for windows that uses a random number generator. This appears to solve the reported issue. I also added the testcase ncdap_test/test_manyurls but made it conditional on --enable-dap-long-tests because it is very slow.
I did note that the provided test program now fails after some 800 iterations with a libcurl error claiming it cannot resolve the host name. My belief is that the library is just running out of resources at this point: too many open curl handles or some such. I doubt if this failure is fixable.
So bottom line is that it is really important to do nc_close when you are finished with a file.
Misc. Other Changes:
1. I took the opportunity to clean up some bad string hacks in the code. Specifically
* change all uses of strncat to strlcat
* remove old string hacks: occoncat and occopycat
2. Add heck to see if test.opendap.org is running and if not, then skip test
3. Make CYGWIN use TEMP environment variable
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.
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.
re: https://github.com/Unidata/netcdf-c/issues/1684
re: e-support VZL-904142
Two issues:
1. As of libcurl 7.66, the semantics of CURLOPT_SSL_VERIFYHOST
changed so that the non-zero values affects certificate processing.
2. The current library was forcing the values of VERIFYPEER
and VERIFYHOST to zero instead of leaving them to the default values.
Solution was first to leave the defaults in place for VERIFYPEER and VERIFYHOST
as long as they are not set in .ocrc/.dodsrc file.
Second, the value of HTTP.SSL.VERIFYPEER or HTTP.SSL.VERIFYHOST
as set in .ocrc/.dodrc is used to set the corresponding CURLOPT flags.
So for example, adding
> HTTP.SSL.VERIFYHOST=2
will set the value of CURLOPT_SSL_VERIFYHOST to 2, the default.
Using
> HTTP.SSL.VERIFYHOST=0
will set the value of CURLOPT_SSL_VERIFYHOST to 0, which disables it.
Similarly for VERIFYPEER.
Finally the semantics of HTTP.SSL.VALIDATE is now equivalent to
> HTTP.SSL.VERIFYPEER=1
> HTTP.SSL.VERIFYHOST=2
I see that there is no way to set CURLOPT_CONNECTTIMEOUT,
but there is support for CURLOPT_TIMEOUT.
So, accept the line 'HTTP.CONNECTTIMEOUT'
in .rc file to allow user to set CURLOPT_CONNECTTIMEOUT.
* For URL paths, the new approach essentially centralizes all information
in the URL into the "#mode=" fragment key and uses that value
to determine the dispatcher for (most) URLs.
* The new approach has the following steps:
1. canonicalize the path if it is a URL.
2. use the mode= fragment key to determine the dispatcher
3. if dispatcher still not determined, then use the mode flags
argument to nc_open/nc_create to determine the dispatcher.
4. if the path points to something readable, attempt to read the
magic number at the front, and use that to determine the dispatcher.
this case may override all previous cases.
* Misc changes.
1. Update documentation
2. Moved some unit tests from libdispatch to unit_test directory.
3. Fixed use of wrong #ifdef macro in test_filter_reg.c
[I think this may fix an previously reported esupport query].
re: https://github.com/Unidata/netcdf-c/issues/1373 (partial)
* Mark some global constants be const to indicate to make them easier to track.
* Hide direct access to the ncrc_globalstate behind a function call.
* Convert dispatch tables to constants (except the user defined ones)
This has some consequences in terms of function arguments needing to be marked
as const also.
* Remove some no longer needed global fields
* Aggregate all the globals in nclog.c
* Uniformly replace nc_sizevector{0,1} with NC_coord_{zero,one}
* Uniformly replace nc_ptrdffvector1 with NC_stride_one
* Remove some obsolete code
re: esupport (DVK-211460)
Turns out it was a typo in libdispatch/dauth.c
Fix is to Change:
HTTP.USERNAME -> HTTP.CREDENTIALS.USERNAME
and
HTTP.PASSWORD-> HTTP.CREDENTIALS.PASSWORD
re: github issue https://github.com/Unidata/netcdf-c/issues/1111
One of the less common use cases for the in-memory feature is
apparently failing with HDF5-1.10.x. The fix is complicated and
requires significant changes to libhdf5/nc4memcb.c. The current
setup is detailed in the file docs/inmeminternal.dox.
Additionally, it was discovered that the program
nc_test/tst_inmemory.c, which is invoked by
nc_test/run_inmemory.sh, actually was failing because of the
above problem. But the failure is not detected since the script
does not return non-zero value.
Other Changes:
1. Fix nc_test_tst_inmemory to return errors correctly.
2. Make ncdap_tests/findtestserver.c and dap4_tests/findtestserver4.c
be generated from ncdap_test/findtestserver.c.in.
3. Make LOG() print output to stderr instead of stdout to
avoid contaminating e.g. ncdump output.
4. Modify the handling of NC_INMEMORY and NC_DISKLESS flags
to properly handle that NC_DISKLESS => NC_INMEMORY. This
affects a number of code pieces, especially memio.c.
Primary change is to cleanup code and remove duplicated code.
1. Unify the rc file reading into libdispatch/drc.c. Eventually extend
if we need rc file for netcdf itself as opposed to the dap code.
2. Unify the extraction from the rc file of DAP authorization info.
3. Misc. other small unifications: make temp file, read file.
4. Avoid use of libcurl when reading file:// because
there is some kind of problem with the Visual Studio version.
Might be related to the winpath problem.
In any case, do direct read instead.
5. Add new error code NC_ERCFILE for errors in reading RC file.
6. Complete documentation cleanup as indicated in this comment
https://github.com/Unidata/netcdf-c/pull/472#issuecomment-325926426
7. Convert some occurrences of #ifdef _WIN32 to #ifdef _MSC_VER
