Sasha Smundak e8652d4cd1 Separate output from diagnostics in Starlark product configuration.

Some of the product configuration makefiles use `info` and `warning` Make's
builtins for diagnostics. As running Starlark configuration generates the makefile
as its output, this diagnostics has to go elsewhere. Implement `rblf_log` as
the functional equivalent of `print` that writes to stderr instead of stdout
and use it to implement `info` and `warning` counterparts.

Fixes: 201073196
Test: manual
Change-Id: Ib4d9c10566f9b20310fbee41eda67f0a621b0a84

2021-09-24 08:54:29 -07:00

2.7 KiB

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Roboleaf configuration files interpreter

Reads and executes Roboleaf product configuration files.

Usage

rbcrun options VAR=value... [ file ]

A Roboleaf configuration file is a Starlark script. Usually it is read from file. The option -c allows to provide a script directly on the command line. The option -f is there to allow the name of a file script to contain (=). (i.e., my=file.rbc sets my to file.rbc, -f my=file.rbc runs the script from my=file.rbc).

Options

-d dir
Root directory for load("//path",...)

-c text
Read script from text

--perf file
Gather performance statistics and save it to file. Use
go tool prof -topfile
to show top CPU users

-f file
File to run.

Extensions

The runner allows Starlark scripts to use the following features that Bazel's Starlark interpreter does not support:

Load statement URI

Starlark does not define the format of the load statement's first argument. The Roboleaf configuration interpreter supports the format that Bazel uses (":file" or "//path:file"). In addition, it allows the URI to end with "|symbol" which defines a single variable symbol with None value if a module does not exist. Thus,

load(":mymodule.rbc|init", mymodule_init="init")

will load the module mymodule.rbc and export a symbol init in it as mymodule_init if mymodule.rbc exists. If mymodule.rbc is missing, mymodule_init will be set to None

Predefined Symbols

rblf_env

A struct containing environment variables. E.g., rblf_env.USER is the username when running on Unix.

rblf_cli

A struct containing the variable set by the interpreter's command line. That is, running

rbcrun FOO=bar myfile.rbc

will have the value of rblf_cli.FOO be "bar"

Predefined Functions

rblf_file_exists(file)

Returns True if file exists

rblf_find_files(top, file-pattern, only_files = 0)

Returns all the paths under top whose basename matches pattern (which is a shell's glob pattern). If only_files is not zero, only the paths to the regular files are returned. The returned paths are relative to top.

rblf_wildcard(glob, top = None)

Expands glob. If top is supplied, expands "top/glob", then removes "top/" prefix from the matching file names.

rblf_regex(pattern, text)

Returns True if text matches pattern.

rblf_shell(command)

Runs sh -c "command", reads its output, converts all newlines into spaces, chops trailing newline returns this string. This is equivalent to Make's shell builtin function. This function will be eventually removed.

rblf_log(arg,..., sep=' ')

Same as print builtin but writes to stderr.

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