Owasm executor on google cloud function

.gitignore

@@ -3,3 +3,5 @@
 *.swp
 *.pyc
 *.log
+
+cloud-function/venv/

CHANGELOG_UNRELEASED.md

@@ -10,6 +10,7 @@
 
 ### Chain
 
+- (feat) [\#1872](https://github.com/bandprotocol/bandchain/pull/1872) Add Owasm executor on Google Cloud function
 - (feat) [\#1951](https://github.com/bandprotocol/bandchain/pull/1951) Add REST endpoint to get genesis file.
 - (feat) [\#1908](https://github.com/bandprotocol/bandchain/pull/1908) Support google cloud function REST executor
 - (feat) [\#1929](https://github.com/bandprotocol/bandchain/pull/1929) Add report info of validator on CLI and REST endpoint.

cloud-function/google_cloud_function.py

@@ -0,0 +1,107 @@
+from flask import Flask, jsonify, json
+import os
+import shlex
+import subprocess
+import base64
+import werkzeug
+from marshmallow import Schema, fields, ValidationError, validate
+
+# Copy and paste this file on Google Cloud function
+# Set environment flag of MAX_EXECUTABLE, MAX_CALLDATA, MAX_TIMEOUT, MAX_STDOUT, MAX_STDERR
+
+
+def get_env(env, flag):
+    if flag not in env:
+        raise Exception(flag + " is missing")
+    return int(env[flag])
+
+
+def success(returncode, stdout, stderr, err):
+    return (
+        jsonify(
+            {"returncode": returncode, "stdout": stdout, "stderr": stderr, "err": err}
+        ),
+        200,
+    )
+
+
+def bad_request(err):
+    return jsonify({"error": err}), 400
+
+
+def execute(request):
+    """Responds to any HTTP request.
+  Args:
+      request (flask.Request): HTTP request object.
+  Returns:
+      The response text or any set of values that can be turned into a
+      Response object using
+      `make_response <http://flask.pocoo.org/docs/1.0/api/#flask.Flask.make_response>`.
+  """
+    env = os.environ.copy()
+
+    MAX_EXECUTABLE = get_env(env, "MAX_EXECUTABLE")
+    MAX_CALLDATA = get_env(env, "MAX_CALLDATA")
+    MAX_TIMEOUT = get_env(env, "MAX_TIMEOUT")
+    MAX_STDOUT = get_env(env, "MAX_STDOUT")
+    MAX_STDERR = get_env(env, "MAX_STDERR")
+
+    class Executable(fields.Field):
+        def _deserialize(self, value, attr, data, **kwargs):
+            try:
+                return base64.b64decode(value).decode()
+            except:
+                raise ValidationError("Can't decoded executable")
+
+    class RequestSchema(Schema):
+        executable = Executable(
+            required=True,
+            validate=validate.Length(max=MAX_EXECUTABLE),
+            error_messages={"required": "field is missing from JSON request"},
+        )
+        calldata = fields.Str(
+            required=True,
+            validate=validate.Length(max=MAX_CALLDATA),
+            error_messages={"required": "field is missing from JSON request"},
+        )
+        timeout = fields.Int(
+            required=True,
+            validate=validate.Range(min=0, max=MAX_TIMEOUT),
+            error_messages={"required": "field is missing from JSON request"},
+        )
+
+    try:
+        request_json = request.get_json(force=True)
+    except werkzeug.exceptions.BadRequest:
+        return bad_request("invalid JSON request format")
+
+    try:
+        loaded_request = RequestSchema().load(request_json)
+    except ValidationError as err:
+        return bad_request(err.messages)
+
+    path = "/tmp/execute.sh"
+    with open(path, "w") as f:
+        f.write(loaded_request["executable"])
+
+    os.chmod(path, 0o775)
+
+    try:
+        timeout_millisec = loaded_request["timeout"]
+        timeout_sec = timeout_millisec / 1000
+
+        proc = subprocess.Popen(
+            [path] + shlex.split(loaded_request["calldata"]),
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+        )
+
+        proc.wait(timeout=timeout_sec)
+        returncode = proc.returncode
+        stdout = proc.stdout.read(MAX_STDOUT).decode()
+        stderr = proc.stderr.read(MAX_STDERR).decode()
+        return success(returncode, stdout, stderr, "")
+    except OSError:
+        return success(126, "", "", "Execution fail")
+    except subprocess.TimeoutExpired:
+        return success(111, "", "", "Execution time limit exceeded")

cloud-function/main.py

@@ -0,0 +1,12 @@
+from flask import Flask, request
+from google_cloud_function import execute
+
+
+def create_app():
+    app = Flask(__name__)
+
+    @app.route("/execute", methods=["POST"])
+    def run():
+        return execute(request)
+
+    return app