cli improvements (#12465)

Features
- add multiple repos by their branch/repo
- generate `pip install` commands and `add_route()` code
![Screenshot 2023-10-27 at 4 49 52
PM](https://github.com/langchain-ai/langchain/assets/9557659/3aec4cbb-3f67-4f04-8370-5b54ea983b2a)

Optimizations:
- group installs by repo/branch to avoid duplicate cloning

libs/cli/tests/test_utils.py

@@ -1,3 +1,5 @@
+from typing import Dict, Optional
+
 import pytest
 
 from langchain_cli.constants import (
@@ -8,44 +10,74 @@ from langchain_cli.constants import (
 from langchain_cli.utils.git import DependencySource, parse_dependency_string
 
 
+def _assert_dependency_equals(
+    dep: DependencySource,
+    *,
+    git: Optional[str] = None,
+    ref: Optional[str] = None,
+    subdirectory: Optional[str] = None,
+    event_metadata: Optional[Dict] = None,
+) -> None:
+    assert dep["git"] == git
+    assert dep["ref"] == ref
+    assert dep["subdirectory"] == subdirectory
+    if event_metadata is not None:
+        assert dep["event_metadata"] == event_metadata
+
+
 def test_dependency_string() -> None:
-    assert parse_dependency_string(
-        "git+ssh://git@github.com/efriis/myrepo.git"
-    ) == DependencySource(
+    _assert_dependency_equals(
+        parse_dependency_string(
+            "git+ssh://git@github.com/efriis/myrepo.git", None, None, None
+        ),
         git="ssh://git@github.com/efriis/myrepo.git",
         ref=None,
         subdirectory=None,
     )
 
-    assert parse_dependency_string(
-        "git+https://github.com/efriis/myrepo.git#subdirectory=src"
-    ) == DependencySource(
+    _assert_dependency_equals(
+        parse_dependency_string(
+            "git+https://github.com/efriis/myrepo.git#subdirectory=src",
+            None,
+            None,
+            None,
+        ),
         git="https://github.com/efriis/myrepo.git",
         subdirectory="src",
         ref=None,
     )
 
-    assert parse_dependency_string(
-        "git+ssh://git@github.com:efriis/myrepo.git#develop"
-    ) == DependencySource(
-        git="ssh://git@github.com:efriis/myrepo.git", ref="develop", subdirectory=None
+    _assert_dependency_equals(
+        parse_dependency_string(
+            "git+ssh://git@github.com:efriis/myrepo.git#develop", None, None, None
+        ),
+        git="ssh://git@github.com:efriis/myrepo.git",
+        ref="develop",
+        subdirectory=None,
     )
 
     # also support a slash in ssh
-    assert parse_dependency_string(
-        "git+ssh://git@github.com/efriis/myrepo.git#develop"
-    ) == DependencySource(
-        git="ssh://git@github.com/efriis/myrepo.git", ref="develop", subdirectory=None
+    _assert_dependency_equals(
+        parse_dependency_string(
+            "git+ssh://git@github.com/efriis/myrepo.git#develop", None, None, None
+        ),
+        git="ssh://git@github.com/efriis/myrepo.git",
+        ref="develop",
+        subdirectory=None,
     )
 
     # looks like poetry supports both an @ and a #
-    assert parse_dependency_string(
-        "git+ssh://git@github.com:efriis/myrepo.git@develop"
-    ) == DependencySource(
-        git="ssh://git@github.com:efriis/myrepo.git", ref="develop", subdirectory=None
+    _assert_dependency_equals(
+        parse_dependency_string(
+            "git+ssh://git@github.com:efriis/myrepo.git@develop", None, None, None
+        ),
+        git="ssh://git@github.com:efriis/myrepo.git",
+        ref="develop",
+        subdirectory=None,
     )
 
-    assert parse_dependency_string("simple-pirate") == DependencySource(
+    _assert_dependency_equals(
+        parse_dependency_string("simple-pirate", None, None, None),
         git=DEFAULT_GIT_REPO,
         subdirectory=f"{DEFAULT_GIT_SUBDIRECTORY}/simple-pirate",
         ref=DEFAULT_GIT_REF,
@@ -53,9 +85,13 @@ def test_dependency_string() -> None:
 
 
 def test_dependency_string_both() -> None:
-    assert parse_dependency_string(
-        "git+https://github.com/efriis/myrepo.git@branch#subdirectory=src"
-    ) == DependencySource(
+    _assert_dependency_equals(
+        parse_dependency_string(
+            "git+https://github.com/efriis/myrepo.git@branch#subdirectory=src",
+            None,
+            None,
+            None,
+        ),
         git="https://github.com/efriis/myrepo.git",
         subdirectory="src",
         ref="branch",
@@ -66,7 +102,10 @@ def test_dependency_string_invalids() -> None:
     # expect error for wrong order
     with pytest.raises(ValueError):
         parse_dependency_string(
-            "git+https://github.com/efriis/myrepo.git#subdirectory=src@branch"
+            "git+https://github.com/efriis/myrepo.git#subdirectory=src@branch",
+            None,
+            None,
+            None,
         )
     # expect error for @subdirectory
 
@@ -77,16 +116,21 @@ def test_dependency_string_edge_case() -> None:
     # this could be a ssh dep with user=a, and default ref
     # or a ssh dep at a with ref=b.
     # in this case, assume the first case (be greedy with the '@')
-    assert parse_dependency_string("git+ssh://a@b") == DependencySource(
+    _assert_dependency_equals(
+        parse_dependency_string("git+ssh://a@b", None, None, None),
         git="ssh://a@b",
         subdirectory=None,
         ref=None,
     )
 
     # weird one that is actually valid
-    assert parse_dependency_string(
-        "git+https://github.com/efriis/myrepo.git@subdirectory=src"
-    ) == DependencySource(
+    _assert_dependency_equals(
+        parse_dependency_string(
+            "git+https://github.com/efriis/myrepo.git@subdirectory=src",
+            None,
+            None,
+            None,
+        ),
         git="https://github.com/efriis/myrepo.git",
         subdirectory=None,
         ref="subdirectory=src",