chore(symdb): upload compressed symbol payloads (#11404)

We add support for compressed symbol database payloads.

## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

ddtrace/internal/symbol_db/symbols.py

@@ -3,6 +3,7 @@
 from dataclasses import field
 import dis
 from enum import Enum
+import gzip
 from http.client import HTTPResponse
 from inspect import CO_VARARGS
 from inspect import CO_VARKEYWORDS
@@ -484,13 +485,18 @@ def upload(self) -> HTTPResponse:
                 ),
                 FormData(
                     name="file",
-                    filename="symdb_export.json",
-                    data=json.dumps(self.to_json()),
-                    content_type="json",
+                    filename=f"symbols_{os.getpid()}.json.gz",
+                    data="[symbols_placeholder]",
+                    content_type="gzip",
                 ),
             ]
         )
 
+        # DEV: The as_bytes method ends up writing the data line by line, which
+        # breaks the final payload. We add a placeholder instead and manually
+        # replace it with the compressed JSON.
+        body = body.replace(b"[symbols_placeholder]", gzip.compress(json.dumps(self.to_json()).encode("utf-8")))
+
         with connector(get_trace_url(), timeout=5.0)() as conn:
             log.debug("[PID %d] SymDB: Uploading symbols payload", os.getpid())
             conn.request("POST", "/symdb/v1/input", body, headers)
@@ -527,7 +533,7 @@ def is_module_included(module: ModuleType) -> bool:
 
 
 class SymbolDatabaseUploader(BaseModuleWatchdog):
-    __scope_limit__ = 100
+    __scope_limit__ = 400
 
     def __init__(self) -> None:
         super().__init__()

ddtrace/internal/utils/http.py

@@ -1,5 +1,6 @@
 from contextlib import contextmanager
 from dataclasses import dataclass
+from email.encoders import encode_noop
 from json import loads
 import logging
 import os
@@ -418,7 +419,7 @@ def parse_message(msg):
 class FormData:
     name: str
     filename: str
-    data: str
+    data: Union[str, bytes]
     content_type: str
 
 
@@ -431,12 +432,12 @@ def multipart(parts: List[FormData]) -> Tuple[bytes, dict]:
     del msg["MIME-Version"]
 
     for part in parts:
-        app = MIMEApplication(part.data, part.content_type, lambda _: _)
+        app = MIMEApplication(part.data, part.content_type, encode_noop)
         app.add_header("Content-Disposition", "form-data", name=part.name, filename=part.filename)
         del app["MIME-Version"]
         msg.attach(app)
 
     # Split headers and body
-    headers, _, body = msg.as_string(policy=HTTP).partition("\r\n\r\n")
+    headers, _, body = msg.as_bytes(policy=HTTP).partition(b"\r\n\r\n")
 
-    return body.encode("utf-8"), dict(_.split(": ") for _ in headers.splitlines())
+    return body, dict(_.split(": ") for _ in headers.decode().splitlines())