Go Package/File Locations - package

From the looks of the go documentation, they make it seem like you have to put code you're working on under your $GOPATH-- is that correct?
I would like to set up a test project in a dir under my ~/Documents, but everytime i run go install example/newmath (like in the test example) it says the following--
λ MacBook-Air src → go install example/newmath
warning: GOPATH set to GOROOT (/usr/local/go) has no effect
can't load package: package example/newmath: import "example/newmath": cannot find package
Does that mean that i need to reset my $GOPATH/$GOROOT? I'm lost.

No need to setup GOROOT in the common situation. GOPATH, OTOH, should be set (and exported).
I would recommend to start with
export GOPATH=$HOME
Then just put a package having import "whatever" into $GOPATH/src/whatever.
You can refine your GOPATH to your needs later, when you get used to how things work with the Go build system (go {build, install}). One can have even multiple items in $GOPATH, but I really don't think it's a concern in the beginning, and sometimes never.

Related

Shows Missing library : ff while building echidna using stack install

I am trying to build echidna using stack install.
https://github.com/crytic/echidna
I am continuously getting the missing library error while installing at a progress state of 171/178.
I believe it to be more of stack error than library error. Error shown is as follows
I have tried installing the library but not getting any C library of such sort.ye
SO, i've installed every library using
sudo apt-get install lib*ff*-dev
isn't working yet.
-- While building package hevm-0.31 using:
/home/aman/.stack/setup-exe-cache/x86_64-linux/Cabal-simple_mPHDZzAJ_2.2.0.1_ghc-8.4.3 --builddir=.stack-work/dist/x86_64-linux/Cabal-2.2.0.1 configure --with-ghc=/home/aman/.stack/programs/x86_64-linux/ghc-8.4.3/bin/ghc --with-ghc-pkg=/home/aman/.stack/programs/x86_64-linux/ghc-8.4.3/bin/ghc-pkg --user --package-db=clear --package-db=global --package-db=/home/aman/.stack/snapshots/x86_64-linux/lts-12.10/8.4.3/pkgdb --package-db=/home/aman/Desktop/new/echidna2/echidna/.stack-work/install/x86_64-linux/lts-12.10/8.4.3/pkgdb --libdir=/home/aman/Desktop/new/echidna2/echidna/.stack-work/install/x86_64-linux/lts-12.10/8.4.3/lib --bindir=/home/aman/Desktop/new/echidna2/echidna/.stack-work/install/x86_64-linux/lts-12.10/8.4.3/bin --datadir=/home/aman/Desktop/new/echidna2/echidna/.stack-work/install/x86_64-linux/lts-12.10/8.4.3/share --libexecdir=/home/aman/Desktop/new/echidna2/echidna/.stack-work/install/x86_64-linux/lts-12.10/8.4.3/libexec --sysconfdir=/home/aman/Desktop/new/echidna2/echidna/.stack-work/install/x86_64-linux/lts-12.10/8.4.3/etc --docdir=/home/aman/Desktop/new/echidna2/echidna/.stack-work/install/x86_64-linux/lts-12.10/8.4.3/doc/hevm-0.31 --htmldir=/home/aman/Desktop/new/echidna2/echidna/.stack-work/install/x86_64-linux/lts-12.10/8.4.3/doc/hevm-0.31 --haddockdir=/home/aman/Desktop/new/echidna2/echidna/.stack-work/install/x86_64-linux/lts-12.10/8.4.3/doc/hevm-0.31 --dependency=QuickCheck=QuickCheck-2.11.3-3XHQpBYb83U2mMvNz2AjQX --dependency=abstract-par=abstract-par-0.3.3-Ie3MD7O3orK6ZR8i7FuBEv --dependency=aeson=aeson-1.3.1.1-7JlrwYHW7OR9ca4RRZ9oOf --dependency=ansi-wl-pprint=ansi-wl-pprint-0.6.8.2-9fh9v74MJQDJeSHE7X3Co6 --dependency=async=async-2.2.1-7DQr5PBcpiwJNOuf7ZiSPa --dependency=base=base-4.11.1.0 --dependency=base16-bytestring=base16-bytestring-0.1.1.6-I0igvRcEwRNBMqqPC2yQBh --dependency=base64-bytestring=base64-bytestring-1.0.0.1-4OCIe2BZn8jKI191JIXI37 --dependency=binary=binary-0.8.5.1 --dependency=brick=brick-0.37.2-HmDqAExuwtV4o98FRmS9eK --dependency=bytestring=bytestring-0.10.8.2 --dependency=cereal=cereal-0.5.7.0-ILaYAmVTyR1IcEsGXXUCfI --dependency=containers=containers-0.5.11.0 --dependency=cryptonite=cryptonite-0.25-GgyZs9E1viv2owjaLxA3vq --dependency=data-dword=data-dword-0.3.1.2-CMzWV6RCGtK8L6wsVSErKS --dependency=deepseq=deepseq-1.4.3.0 --dependency=directory=directory-1.3.1.5 --dependency=fgl=fgl-5.6.0.0-E3fRSNebqkULRqplV3ljSc --dependency=filepath=filepath-1.4.2 --dependency=ghci-pretty=ghci-pretty-0.0.2-I5PJbL8ge6MChp3KxZbHqH --dependency=haskeline=haskeline-0.7.4.3-5EI2v7Zmtnz57a7mmnEGOS --dependency=lens=lens-4.16.1-B0f4CyKKTUGAKBzzY965AX --dependency=lens-aeson=lens-aeson-1.0.2-Jly9eqrxMbj6GutGwOKn69 --dependency=megaparsec=megaparsec-6.5.0-G48ltiRFbVUHATB1lTnNRx --dependency=memory=memory-0.14.16-GTCi0eCrvrnI3inLDBWVMK --dependency=monad-par=monad-par-0.3.4.8-Jjk0JT5qYVK4xEO13GFUu8 --dependency=mtl=mtl-2.2.2 --dependency=multiset=multiset-0.3.4.1-DOPR5uXspss8vZY4jdOdOo --dependency=operational=operational-0.2.3.5-4jEcCWo4nKu1T4LZlKqe58 --dependency=optparse-generic=optparse-generic-1.3.0-1jcIewFKPXBLcRetZisV2l --dependency=process=process-1.6.3.0 --dependency=quickcheck-text=quickcheck-text-0.1.2.1-2lR7Kay7WBV5AMKAdKDpZZ --dependency=regex-tdfa=regex-tdfa-1.2.3.1-9PkkapJrmiKFVG38JA02jN --dependency=restless-git=restless-git-0.7-83nBoDMPYLtJIx01bvXzKs --dependency=rosezipper=rosezipper-0.2-GAlMD5j8Qb83GzjCYQknnx --dependency=s-cargot=s-cargot-0.1.4.0-J9AhWfrUxDQ6YMTyzXkHth --dependency=scientific=scientific-0.3.6.2-5di0UflhS5I1xpiiCPzjKz --dependency=semver-range=semver-range-0.2.7-dBvW3ofcsgDQf0zazTsJd --dependency=temporary=temporary-1.3-5Z6bOFbSCb7VhnH5UnI2r --dependency=text=text-1.2.3.0 --dependency=text-format=text-format-0.3.2-Fd261TSu6ptAAzilVN6BFx --dependency=time=time-1.8.0.2 --dependency=transformers=transformers-0.5.5.0 --dependency=tree-view=tree-view-0.5-Kkrk0dCM0oj2Q4xwPbd7Gg --dependency=unordered-containers=unordered-containers-0.2.9.0-IkfpzvG0LzrHAbTzfMidvY --dependency=vector=vector-0.12.0.1-4awQG9XUvVEBfJgKGHBhOb --dependency=vty=vty-5.21-A2OCwk39Wv3J3RjR3BvHey --dependency=witherable=witherable-0.2-2RYbFmOnVolGAqiDDS1CLe --dependency=wreq=wreq-0.5.2.1-IjuXB0jwsxA7O3uIVjcJXu --extra-include-dirs=/home/aman/Downloads/Compressed/ff13c/source/ --extra-include-dirs=/usr/local/opt/readline/include --extra-lib-dirs=/usr/local/opt/readline/lib
Process exited with code: ExitFailure 1
Logs have been written to: /home/aman/Desktop/new/echidna2/echidna/.stack-work/logs/hevm-0.31.log
Configuring hevm-0.31...
Cabal-simple_mPHDZzAJ_2.2.0.1_ghc-8.4.3: Missing dependency on a foreign
library:
* Missing (or bad) C library: ff
This problem can usually be solved by installing the system package that
provides this library (you may need the "-dev" version). If the library is
already installed but in a non-standard location then you can use the flags
--extra-include-dirs= and --extra-lib-dirs= to specify where it is.If the
library file does exist, it may contain errors that are caught by the C
compiler at the preprocessing stage. In this case you can re-run configure
with the verbosity flag -v3 to see the error messages.
The stack install must find this library and end up successfully installing the library I'm using.
So, it is clear from the error provided above, that the installation was not able to find the libff file.
The best solution is to build the libff library manually and copy the required builds at the place it should be.
The best way to debug the problem is to look at the executed command closely and try to find the possible places where the libff should be...
Looking into the very 2nd error line, i.e. the complete command it was trying to execute
here, I sighted the following options being executed
--extra-include-dirs=/usr/local/opt/readline/include --extra-lib-dirs=/usr/local/opt/readline/lib
In order to solve this, I looked for the required libff library and cloned it from GitHub. I cloned the required dependencies and places them in the directory it should be.
https://github.com/scipr-lab/libff
I then followed the "Build guide" to build the required library.
Then with the superuser on, I created the directories, /usr/local/opt/readline/lib and /usr/local/opt/readline/include, and it was solved. And pasted the required builds in it.
Used stack install again, and it worked.
Note:
I thought many beginners may have similar problem while installing the required tools for their use. These small ideas may help them.

Is there a way to run shake assuming some rule is up-to-date?

We would like to run a Shake build while assuming some target is built, e.g. something like
./Build.hs --dont-rebuild my-target
Reading the docs it seems there should be a way to do that but I can't find it.
The ShakeOptions setting you are looking for is shakeRebuild=[(RebuildLater,"my-target")]. This setting causes Shake to not rebuild my-target in this run. From the documentation of RebuildLater:
This assumption is unsafe, and may lead to incorrect build results in this run. Assume these files are clean in this run, but test them normally in future runs.
This setting can be applied using the command line --skip=my-target. A few caveats:
my-target won't rebuild in this run, by things it depends on might, if they need to.
If you next run without skipping my-target, it will rebuild if it needs to (the --skip is not sticky).

BitBake: example not found in the base feeds

I have a BitBake recipe (example_0.1.bb) with a do_install task where I attempt to install a .so file:
do_install() {
install -d ${D}${libdir}
install -m 0644 ${S}/example.so ${D}${libdir}
}
FILES_${PN} += "${libdir}/example.so"
This fails during the build process and returns:
ERROR: example not found in the base feeds
However, if I add a test file to the package, both the .so file and the test file are added to the rootfs.
do_install() {
install -d ${D}${libdir}
install -m 0644 ${S}/example.so ${D}${libdir}
echo "bar" >> ${TOPDIR}/foo
install -m 0644 ${TOPDIR}/foo ${D}${libdir}
}
FILES_${PN} += "${libdir}/libceill.so"
FILES_${PN} += "${libdir}/foo"
How can I add only the .so file without the junk test file?
So you've got a library that is non-standard in that it's not installing a versioned library (libfoo.so.1.2.3, maybe symlinks such as libfoo.so.1 -> libfoo.so.1.2.3), and then an unversioned symlink for compilation time (libfoo.so -> libfoo.so.1). The default packaging rules assume standard libraries.
What's happening is that packages are populated by their order in PACKAGES, which has PN-dev before PN. FILES_PN-dev by default contains /usr/lib/lib*.so, and FILES_PN contains /usr/lib/lib*.so.. When you add /usr/lib/lib.so to FILES_PN what you want to happen isn't happening because PN-dev has already taken the files.
If your library doesn't come with any development files at all (e.g. no headers) then you can set FILES_${PN}-dev = "" to empty that package, and then your addition of lib*.so to FILES_${PN} will work as expected.
Yes, this is something that we should make easier (I've been thinking about a small class for libraries like this) and warn in sanity checks when it happens.
Oh and I'm surprised that the library ends up in the image in your second example, as example will contain /usr/lib/foo and example-dev will contains /usr/lib/libceill.so. Unless of course you've got dev-pkgs enabled, which will automatically install example-dev if you've got example in an image.
Add the line
FILES_SOLIBSDEV = ""
An explanation from the Yocto mailing list:
I had FILES_${PN} += “${libdir}/.so” in there and that didn't work.
Maybe it was because I was missing the FILES_SOLIBSDEV = “" you mentioned.
I'll play with it some more and see what happens. I first started out with
FILES_${PN} += “${libdir}/.so” and when that didn't work I tried other
things in the FILES_${PN} = line to try and get it picked up. When I
couldn't get any of it to work and then saw others (well, at least the link
I provided) were seeing the same thing I figured it was time to quit
spinning my wheels and consult the big guns :)
Heh :) The issue there is that the patterns are matched in the order of the
PACKAGES variable. The first package to include a file gets it, and
${PN}-dev is in PACKAGES before ${PN}. By emptying FILES_SOLIBSDEV, that’ll
remove the .so from FILES_${PN}-dev, letting the ${PN} package get it
instead.
Add the line:
FILES_${PN}_dev_remove="${FILES_SOLIBDEV} "
It will move out the package for development path.

Osgviewer cow does not view a cow?

I installed OpenSceneGraph 3.0.1using MacPorts.
I've tried osgversion -> OpenSceneGraph Library 3.0.1. I downloaded the OpenSceneGraph-Data.
Everything seems working well than osgviewer cow.osg takes hours without viewing anything !
please I need help ? is there a way to debug ?
Make sure you have defined the OSG_FILE_PATH environment variable and that it points to the data directory (the one with 'cow.osg').
You can then set OSG_NOTIFY_LEVEL to DEBUG_INFO to get extended information printed to the console. If for any reason the file could not be loaded correctly you will see where to start to troubleshoot.
You can also try to run
$ osgviewer --image /path/to/an/image.png
to test if the plugins work correctly.
Plugins are named e.g. osgdb_jpeg.dylib so you can look for these to make sure they have been built properly along with the core libraries and programs.
Try setting the notify level to DEBUG : Tips And Tricks
$ export OSG_NOTIFY_LEVEL=DEBUG
and run it and see if it says what's going on/going wrong.

How to find the "current" source file in Python 3?

What's the simplest way to find the path to the file in which I am "executing" some code? By this, I mean that if I have a file foo.py that contains:
print(here())
I would like to see /some/path/foo.py (I realise that in practice what file is "being executed" is complicated, but I think the above is well defined - a source file that contains some function that, when executed, gives the path to said file).
I have needed this in the past to make tests (that require some external file) self-contained, and I am currently wondering if it would be a useful way to locate some support files needed by a program. But I have never found a good way of doing this. The inspect module sounds like it should work, but you seem to need a class or function that is defined in that module.
In particular, the module instances contain __file__ attributes, but I can't see how to get the "current" module. Objects have a __module__ attribute, but that's the module name, not a module instance.
I guess one way is to throw and catch an exception and inspect the contents, but that seems like hard work. Surely there is a simple, easy way that I have missed?
To get the absolute path of the current file:
import os
os.path.abspath(__file__)
To get content of external file distributed with your package you could use pkg_util.get_data()(stdlib) or pkg_resources.resouce_string() (setuptools) to support execution from zip-archives or standalone executables created by py2exe, PyInstaller or similar, example.

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