I have a target in waf defined like this:
bld(...,
target='asdf',
export_includes='.'
)
I want to get the value of the export_includes for that target (for use in some custom commands).
How do I get it?
Use a custom rule with the features for whatever target you're processing. Ex, let's say I'm processing C:
def print_includes(t):
print(t.env.INCPATHS)
bld(features='c', use='asdf', rule=print_includes)
The task t's env will contain all relevant environment variables as derived from the bld.env, but with all the additional flags stemming from use-ing the target.
i.e. if I originally had bld.env.INCPATHS == ['old-path' 'other-old-path'], it'll end up being printed out as ['old-path', 'other-old-path', 'export_include_for_asdf_here'].
Related
I would like to be able to do the following in a Bazel BUILD file:
alpha(
name = "hello world",
color = "blue"
)
beta(
name = "hello again"
)
Where alpha and beta are custom rules. I want beta to be able to access the color attribute of the alpha rule, without adding a label attribute. In Bazel query, I can do something like this:
bazel query 'kind(beta, siblings(kind(alpha, //...)))'
which gives me the beta which is side by side to alpha. Can I achieve the same somehow from within the implementation function of the beta rule?
def _beta_rule_impl(ctx):
# This does not exist, I wish it did: ctx.siblings(kind='alpha')
I've seen this been done with a label like this
beta(
name = "hello again",
alpha_link = ":hello world" # explicitly linking
)
but I find this a bit verbose, especially since there is a sibling query support.
The way the question is formulated, the answer is no. It is not possible.
Bazel design philosophy is to be explicit about target dependencies. Providers mechanism is meant to provide the access to the dependency graph information during the analysis phase.
It is difficult to tell what is the actual use case is. Using Aspects might be the answer.
In my scenario, I'm trying to get a genrule to call a test rule before proceeding:
genrule(
name = "generate_buf_image",
srcs = [":protos", "cookie"],
outs = ["buf-image.json"],
cmd = "$(location //third_party/buf:cas_buf_image) //example-grpc/proto/v1:proto_backwards_compatibility_check $(SRCS) >$(OUTS)",
tools = [
"//third_party/buf:cas_buf_image",
"#buf",
],
)
If cas_buf_image.sh has ls -l "example-grpc/proto/v1" >&2, it shows:
… cookie -> …/example-grpc/proto/v1/cookie
… example.proto -> …/example-grpc/proto/v1/example.proto
IOW, examining what example-grpc/proto/v1/cookie is linked to and cding to its directory then performing the git commands should work.
In Bazel, how do I fetch a remote file as a build rule not as a WORKSPACE rule?
I want to use a build rule because WORKSPACE rules are not loaded for transitively.
e.g. this fails
load("#bazel_tools//tools/build_defs/repo:http.bzl", "http_file")
http_file(
name = "foo",
urls = [ "https://example.com" ],
sha256 = "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
executable = True,
)
Error in repository_rule: 'repository rule http_file' can only be called during workspace loading
If you really want to do that, you have to implement your own rule, a naïve trivial example relying on curl to fetch could be:
def _impl(ctx):
args = ctx.actions.args()
args.add("-o", ctx.outputs.out)
args.add(ctx.attr.url)
ctx.actions.run(
outputs = [ctx.outputs.out],
executable = "curl",
arguments = [args],
)
get_stuff = rule(
_impl,
attrs = {
"url": attr.string(
mandatory = True,
),
},
outputs = {"out": "%{name}.out"},
)
But (and esp. in such a trivial) for, it comes with problems. Apart from, do you want to step out of sandbox during the build? And do you want to talk to someone across the network during the build (out of the sandbox)? Bypassing repository_cache, and possibly getting remote_cache involved (networked caching of networked fetching). Specifically in this example, if content of the file pointed to by url changes... build has no idea and only fetches it when it either hasn't done so or the url itself has changed. I.e. the implementation would need to be more robust (mimic that of http_file for instance).
But it actually sounds like you're trying to address a different problem (transitive external dependencies, for which there could be another solution). One trick used for that is to define a macro (in your first level dependency to load define the next hop) and after declaring that first step as an external dependency in your parent project, load the that macro and use it from parent project WORKSPACE. This too has a price though, namely the first level dependency has to always be present (fetched or already cached), even if build target asked for does not actually need it (as that load and macro call will always pull it in).
I'm working on implementing a feature like Strict Java Deps for rules_scala.
I'd really like to have the ability to configure in runtime if this uses warn or error.
I seem to recall skylark rules can't create and access command-line flags but I don't recall if they can access existing ones?
Main difference is that existing ones are already parsed so maybe they are also passed in some ctx.
The flag you want (strict_java_deps) isn't available through Skylark at the moment. There's no reason we can't add it, though, filed #3295 to track.
For other flags, the context can access the configuration fragments, which can access some of the parsed command line flags. I think what you'd want is ctx.fragments, then use the fragments to get the java fragments, and then get the default_javac_flags from that:
# rules.bzl
def _impl(ctx):
print("flags: %s" % ctx.fragments.java.default_javac_flags)
...
frag = rule(
implementation = _impl,
fragments = ["java"], # Declare that this rule uses java fragments
)
Then:
$ bazel build --javacopt="-g:source,lines" :x
WARNING: /home/kchodorow/test/a/tester.bzl:2:3: flags: ["-g:source,lines"].
I need to find the name of the Lua executeable from within a Lua script as it sets up a task for later execution.
Using arg I can find out the name, however this becomes un reliable if options are used. For example, if no arguments are used running within a script print( arg[-1]) would print lua53. However if options are used they would be printed instead, such as -i, and to get the exe I would have change the line to print( arg[-2]).
What method will reliably get the name of the lua binary?
Try this
i=0
repeat i=i-1 until arg[i]==nil
i=i+1
print(i,arg[i])
I am trying to minimize my Robot Keywords and in my URL testing I sometimes have to build up a URL from a group of inputs, that can vary depending on the test. The length can be anywhere from 4 to 7 input parameters that I am catenating to pass back one URL with whatever input parameters are passed in.
If I have a keyword that does the following:
inputs: ${location01} ${location02} ${location03}=${EMPTY} ${location04}=${EMPTY}
${my_url} = Catenate SEPARATOR=/ ${location01} ${location02} ${location03} ${location04}
[Return] ${my_url}
What is the best method to test if ${location03} is empty, and I can therefore skip the rest?
When I have tried to test for ${EMPTY}, so that the following will be false
${my_url} Run Keyword IF '${location03}'!='${EMPTY} Catenate SEPARATOR=/ ${location01} ${location02} ${location03} ${location04}
I still get a catenated string but end up with extra /'s at the end, so ${my_url} looks like:
${my_url} = ${location01}/${location02}//
When I want:
${my_url} = ${location01}/${location02}
I may be missing how Robot is doing checks, and initializing my variables, I'm sure there is a way to do this that is eluding me at the moment.
Sounds like you need to use #{args} to handle variable number of parameters:
*** Keywords ***
Create URL
[Arguments] #{args}
${url}= Catenate SEPARATOR=/ #{args}
*** Test Cases ***
Test Url
Create URL http://stackoverflow.com questions robotframework
Create URL http://stackoverflow.com questions