Merge pull request #47 from lumapps/fix_go_lib

fix: fixed a bug making impossible to install the Go lib

Author: Ilan Piperno

.circleci/config.yml

@@ -32,7 +32,7 @@ jobs:
           name: Check dependencies
           command: |
             source venv/bin/activate && \
-            PYTHONPATH=. GOPATH=dep_check/lib python3.7 dep_check/main.py check dep_check
+            PYTHONPATH=. python3.7 dep_check/main.py check dep_check
 
   # Run the unit tests
   tests:

dep_check/infra/go_parser.py

@@ -1,64 +1,33 @@
 import logging
-from ctypes import Structure, c_char_p, c_longlong, cdll
-from os import environ
+from os import chdir
 from subprocess import CalledProcessError, run
 
 from dep_check.dependency_finder import IParser
 from dep_check.models import Dependencies, Dependency, ModuleWildcard, SourceFile
 
-
-class GoString(Structure):  # pylint: disable=too-few-public-methods
-    _fields_ = [("data", c_char_p), ("n", c_longlong)]
+try:
+    from dep_check.lib import goparse
+except ImportError:
+    chdir("dep_check/lib")
+    try:
+        run(["go", "build", "-buildmode=c-shared", "-o", "goparse.so"], check=True)
+        from dep_check.lib import goparse  # pylint: disable=no-name-in-module
+    except (CalledProcessError, FileNotFoundError):
+        logging.warning(
+            "Couldn't load GO library, you won't be able to use dep-check on GO projects."
+        )
+    except ImportError:
+        logging.warning(
+            "Couldn't importy GO library, you won't be able to use dep-check on GO projects."
+        )
+    chdir("../..")
 
 
 class GoParser(IParser):
     """
     Implementation of the interface, to parse go
     """
 
-    def __init__(self):
-        self.lib_path = environ.get("GOLIB", f'{environ["HOME"]}/.dep-check')
-
-        try:
-            self.lib = cdll.LoadLibrary(f"{self.lib_path}/go_parse.so")
-        except OSError:
-            logging.info("go_parse.so not found. Building...")
-            try:
-                run(
-                    ["go", "get", "-d", "github.com/lumapps/dep-check/dep_check/lib"],
-                    check=True,
-                )
-                run(
-                    [
-                        "go",
-                        "build",
-                        "-o",
-                        f"{self.lib_path}/go_parse.so",
-                        "-buildmode=c-shared",
-                        "$GOPATH/src/github.com/lumapps/dep-check/dep_check/lib/go_parse.go",
-                    ],
-                    check=True,
-                )
-                environ["GOLIB"] = self.lib_path
-                logging.info("GO lib go_parse.so built")
-
-            except CalledProcessError:
-                logging.error(
-                    "Unable to build the GO lib from "
-                    "github.com/lumapps/dep-check/dep_check/lib"
-                )
-                raise
-
-            try:
-                self.lib = cdll.LoadLibrary(f"{self.lib_path}/go_parse.so")
-                # After building the lib, we try to load it again
-            except OSError:
-                logging.error("Error while loading the library. Please try again")
-                raise
-
-        self.lib.FindDependencies.argtypes = [GoString]
-        self.lib.FindDependencies.restype = GoString
-
     def wildcard_to_regex(self, module: ModuleWildcard) -> str:
         """
         Return a regex expression for the Module from wildcard
@@ -71,12 +40,10 @@ def wildcard_to_regex(self, module: ModuleWildcard) -> str:
         return module_regex
 
     def find_dependencies(self, source_file: SourceFile) -> Dependencies:
-        if source_file.code == "":
+        if not source_file.code:
             return set()
-        deps_string = self.lib.FindDependencies(
-            GoString(source_file.code.encode(), len(source_file.code))
-        )
-        deps_list = deps_string.data.decode("utf-8").replace('"', "").split(";")[:-1]
+        deps_string = goparse.find_dependencies(source_file.code)
+        deps_list = deps_string.replace('"', "").split(";")[:-1]
 
         dependecies: Dependencies = {Dependency(dep) for dep in deps_list}
         return dependecies

dep_check/lib/find_dependencies.go

@@ -0,0 +1,41 @@
+package main
+
+// #cgo pkg-config: python3
+// #define Py_LIMITED_API
+// #include <Python.h>
+// int PyArg_ParseTuple_str(PyObject *, char **);
+// PyObject * Py_BuildValue_str(PyObject * args, char * src);
+import "C"
+
+import (
+	"fmt"
+	"go/parser"
+	"go/token"
+)
+
+//export find_dependencies
+func find_dependencies(self, args *C.PyObject) *C.PyObject {
+	var src *C.char
+	if C.PyArg_ParseTuple_str(args, &src) == 0 {
+		return nil
+	}
+
+	fset := token.NewFileSet() // positions are relative to fset
+
+	// Parse src but stop after processing the imports.
+	f, err := parser.ParseFile(fset, "", C.GoString(src), parser.ImportsOnly)
+	if err != nil {
+		fmt.Println(err)
+		return nil
+	}
+
+	// Print the imports from the file's AST.
+	dependencies := ""
+	for _, s := range f.Imports {
+		dependencies += s.Path.Value + ";"
+	}
+
+	return C.Py_BuildValue_str(self, C.CString(dependencies))
+}
+
+func main() {}

dep_check/lib/go_parse.go

@@ -0,0 +1,29 @@
+#define Py_LIMITED_API
+#include <Python.h>
+
+PyObject * find_dependencies(PyObject *, PyObject *);
+
+// Workaround missing variadic function support
+// https://github.com/golang/go/issues/975
+int PyArg_ParseTuple_str(PyObject * args, char ** src) {
+    return PyArg_ParseTuple(args, "s", src);
+}
+
+static PyMethodDef GoParseMethods[] = {
+    {"find_dependencies", find_dependencies, METH_VARARGS, "Parses a file and returns its dependencies."},
+    {NULL, NULL, 0, NULL}
+};
+
+static struct PyModuleDef goparsemodule = {
+   PyModuleDef_HEAD_INIT, "goparse", NULL, -1, GoParseMethods
+};
+
+PyObject * Py_BuildValue_str(PyObject * args, char * src) {
+    return Py_BuildValue("s", src);
+}
+
+PyMODINIT_FUNC
+PyInit_goparse(void)
+{
+    return PyModule_Create(&goparsemodule);
+}

dep_check/lib/goparse.c

@@ -136,8 +136,7 @@ def main(self) -> int:
         self.create_app_configuration()
         try:
             use_case = DEP_CHECK_FEATURES[self.feature].use_case_factory(self)
-            use_case.run()
-
+            code = use_case.run()
         except KeyError:
             raise MissingOptionError()
 

dep_check/main.py

@@ -14,6 +14,9 @@ dependency_rules:
   dep_check.infra.std_lib_filter:
     - dep_check.use_cases.interfaces
 
+  dep_check.infra.go_parser:
+    - dep_check.lib.goparse
+
   dep_check.use_cases%:
     - dep_check.use_cases.app_configuration
     - dep_check.use_cases.interfaces

dependency_config.yaml

@@ -55,3 +55,6 @@ known_third_party=flask,google,marshmallow,sqlalchemy,yaml,structlog
 line_length=88
 multi_line_output=3
 use_parentheses=True
+
+[mypy-dep_check.lib]
+ignore_missing_imports = True