Underlying volume data may have been removed by some other tool.
Ignore and remove the reference in this case.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
For now CLI `docker stats` will not block even if the container was
not running is because there is a 2s timeout setting when waiting for
the response.
I think why we hang there waiting for the container to run is because we
want to get the stats of container immediately when it starts running.
But it will block when use the API directly, for example
- curl
- Google Chrome plugin, Postman
- Firefox plugin, RESTClient
This patch keeps the feature that getting info immediately when container
starts running and in the meantime, it will not block when using the API
directrly.
Signed-off-by: Hu Keping <hukeping@huawei.com>
TL;DR: stop building static binary that may fail
Linker flag --unresolved-symbols=ignore-in-shared-libs was added
in commit 06d0843 two years ago for the static build case, presumably
to avoid dealing with problem of missing libraries.
For the record, this is what ld(1) man page says:
> --unresolved-symbols=method
> Determine how to handle unresolved symbols. There are four
> possible values for method:
> .........
> ignore-in-shared-libs
> Report unresolved symbols that come from regular object files,
> but ignore them if they come from shared libraries. This can
> be useful when creating a dynamic binary and it is known that
> all the shared libraries that it should be referencing are
> included on the linker's command line.
Here, the flag is not used for its purpose ("creating a dynamic binary")
and does more harm than good. Instead of complaining about missing symbols
as it should do if some libraries are missing from LIBS/LDFLAGS, it lets
ld create a binary with unresolved symbols, ike this:
$ readelf -s bundles/1.7.1/binary/docker-1.7.1 | grep -w UND
........
21029: 0000000000000000 0 NOTYPE GLOBAL DEFAULT UND dlopen
.........
Such binary is working just fine -- until code calls one of those
functions, then it crashes (for apparently no reason, i.e. it is
impossible to tell why from the diagnistics printed).
In other words, adding this flag allows to build a static binary
with missing libraries, hiding the problem from both a developer
(who forgot to add a library to #cgo: LDFLAGS -- I was one such
developer a few days ago when I was working on ploop graphdriver)
and from a user (who expects the binary to work without crashing,
and it does that until the code calls a function in one of those
libraries).
Removing the flag immediately unveils the problem (as it should):
/usr/lib/gcc/x86_64-linux-gnu/4.8/../../../x86_64-linux-gnu/libsqlite3.a(sqlite3.o):
In function `unixDlError':
(.text+0x20971): undefined reference to `dlerror'
/usr/lib/gcc/x86_64-linux-gnu/4.8/../../../x86_64-linux-gnu/libsqlite3.a(sqlite3.o):
In function `unixDlClose':
(.text+0x8814): undefined reference to `dlclose'
The problem is, gosqlite package says:
#cgo LDFLAGS: -lsqlite3
which is enough for dynamic linking, as indirect dependencies (i.e.
libraries required by libsqlite3.so) are listed in .so file and will be
resolved dynamically by ldd upon executing the binary.
For static linking though, one has to list all the required libraries,
both direct and indirect. For libraries with pkgconfig support the
list of required libraries can be obtained with pkg-config:
$ pkg-config --libs sqlite3 # dynamic linking case
-lsqlite3
$ pkg-config --libs --static sqlite3 # static case
-lsqlite3 -ldl -lpthread
It seems that all one has to do is to fix gosqlite this way:
-#cgo LDFLAGS: -lsqlite3
+#cgo pkg-config: sqlite3
Unfortunately, cmd/go doesn't know that it needs to pass --static
flag to pkg-config in case of static linking
(see https://github.com/golang/go/issues/12058).
So, for one, one has to do one of these things:
1. Patch sqlite.go like this:
-#cgo LDFLAGS: -lsqlite3
+#cgo pkg-config: --static sqlite3
(this is exactly what I do in goploop, see
https://github.com/kolyshkin/goploop/commit/e9aa072f51)
2. Patch sqlite.go like this:
-#cgo LDFLAGS: -lsqlite3
+#cgo LDFLAGS: -lsqlite3 -ldl -lpthread
(I would submit this patch to gosqlite but it seems that
https://code.google.com/p/gosqlite/ is deserted and not maintained,
and patching it here is not right as it is "vendored")
3. Explicitly add -ldl for the static link case.
This is what this patch does.
4. Fork sqlite to github and maintain it there. Personally I am not
ready for that, as I'm neither a Go expert nor gosqlite user.
Now, #3 doesn't look like a clear solution, but nevertheless it makes
the build much better than it was before.
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
