Expose freeze-deps as a buildable target (#31)

README.md

@@ -522,7 +522,7 @@ file you need to do the following:
 
    pinned_maven_install()
    ```
-2. Run `./tools/freeze-deps.py --repo <repo name> --zip
+2. Run `bazel run //tools:freeze-deps -- --repo <repo name> --zip
    <path/to/dependency.zip>`. The `<repo name>` matches the name used
    for the `maven_install()` rule above. This will pin the
    dependencies then collect them into the zip file.

tools/BUILD.bazel

@@ -14,3 +14,11 @@ java_binary(
     main_class = "com.google.googlejavaformat.java.Main",
     runtime_deps = ["@maven//:com_google_googlejavaformat_google_java_format"],
 )
+
+py_binary(
+    name = "freeze-deps",
+    srcs = [
+        "freeze-deps.py",
+    ],
+    visibility = ["//visibility:public"],
+)

tools/freeze-deps.py

@@ -32,22 +32,28 @@
     help="Name of the zip repository used to import the zip file. Used only if compat_repositories are enabled"
 )
 
+# When run under `bazel run` this directory will be set. If not,
+# then we should assume our current directory is the right one
+# to use.
+cwd = os.environ.get("BUILD_WORKSPACE_DIRECTORY", None)
+
 args = parser.parse_args()
 
 pin_env = {"REPIN": "1"}
 pin_env.update(os.environ)
 
 # Repin our dependencies
 cmd = ["bazel", "run", "@unpinned_%s//:pin" % args.repo]
-subprocess.check_call(cmd, env=pin_env)
+subprocess.check_call(cmd, env=pin_env, cwd = cwd)
 
 # Now grab the files we need from their output locations
 cmd = ["bazel", "info", "output_base"]
-output_base = subprocess.check_output(cmd).rstrip()
+output_base = subprocess.check_output(cmd, cwd = cwd).rstrip()
 base = output_base.decode(encoding=sys.stdin.encoding)
 
 # Generate a stable-ish zip file
-output = zipfile.ZipFile(args.zip, "w", zipfile.ZIP_DEFLATED)
+zip_path = path.join(cwd, args.zip) if cwd else args.zip
+output = zipfile.ZipFile(zip_path, "w", zipfile.ZIP_DEFLATED)
 
 for f in UNCHANGED_FILES:
     p = path.join(base, "external", args.repo, f)