From affa0f0149ec5423656eb9c966974b3741e530db Mon Sep 17 00:00:00 2001
From: Iain Learmonth <irl@sr2.uk>
Date: Mon, 29 Aug 2022 19:16:35 +0100
Subject: [PATCH] tfstate: very basic terraform state backend in flask

---
 app/__init__.py                               |  2 +
 app/models/tfstate.py                         |  7 +++
 app/tfstate.py                                | 51 +++++++++++++++++++
 .../665e340dbe09_add_terraform_state.py       | 28 ++++++++++
 4 files changed, 88 insertions(+)
 create mode 100644 app/models/tfstate.py
 create mode 100644 app/tfstate.py
 create mode 100644 migrations/versions/665e340dbe09_add_terraform_state.py

diff --git a/app/__init__.py b/app/__init__.py
index ada98d7..0bb8b95 100644
--- a/app/__init__.py
+++ b/app/__init__.py
@@ -6,6 +6,7 @@ from app.extensions import db
 from app.extensions import migrate
 from app.extensions import bootstrap
 from app.portal import portal
+from app.tfstate import tfstate
 
 app = Flask(__name__)
 app.config.from_file("../config.yaml", load=yaml.safe_load)
@@ -14,6 +15,7 @@ migrate.init_app(app, db, render_as_batch=True)
 bootstrap.init_app(app)
 
 app.register_blueprint(portal, url_prefix="/portal")
+app.register_blueprint(tfstate, url_prefix="/tfstate")
 
 
 @app.route('/')
diff --git a/app/models/tfstate.py b/app/models/tfstate.py
new file mode 100644
index 0000000..62dbf9a
--- /dev/null
+++ b/app/models/tfstate.py
@@ -0,0 +1,7 @@
+from app.extensions import db
+
+
+class TerraformState(db.Model):
+    key = db.Column(db.String, primary_key=True)
+    state = db.Column(db.String)
+    lock = db.Column(db.String)
diff --git a/app/tfstate.py b/app/tfstate.py
new file mode 100644
index 0000000..bfa58dd
--- /dev/null
+++ b/app/tfstate.py
@@ -0,0 +1,51 @@
+import json
+
+from flask import Blueprint, request, Response
+
+from app.extensions import db
+from app.models.tfstate import TerraformState
+
+tfstate = Blueprint("tfstate", __name__)
+
+
+@tfstate.route("/<key>", methods=['GET'])
+def handle_get(key):
+    state = TerraformState.query.filter(TerraformState.key == key).first()
+    if state is None or state.state is None:
+        return "Not Found", 404
+    return Response(state.state, content_type="application/json")
+
+
+@tfstate.route("/<key>", methods=['POST', 'DELETE', 'UNLOCK'])
+def handle_update(key):
+    state = TerraformState.query.filter(TerraformState.key == key).first()
+    if not state:
+        if request.method in ["DELETE", "UNLOCK"]:
+            return "OK", 200
+        state = TerraformState(key=key)
+    if state.lock and not (request.method == "UNLOCK" and request.args.get('ID') is None):
+        if json.loads(state.lock)['ID'] != request.args.get('ID'):
+            return Response(state.lock, status=409, content_type="application/json")
+    if request.method == "POST":
+        state.state = json.dumps(request.json)
+    elif request.method == "DELETE":
+        db.session.delete(state)
+    elif request.method == "UNLOCK":
+        state.lock = None
+    db.session.commit()
+    return "OK", 200
+
+
+@tfstate.route("/<key>", methods=['LOCK'])
+def handle_lock(key):
+    state = TerraformState.query.filter(TerraformState.key == key).with_for_update().first()
+    if state is None:
+        state = TerraformState(key=key)
+        db.session.add(state)
+    if state.lock is not None:
+        lock = state.lock
+        db.session.rollback()
+        return Response(lock, status=423, content_type="application/json")
+    state.lock = json.dumps(request.json)
+    db.session.commit()
+    return "OK", 200
diff --git a/migrations/versions/665e340dbe09_add_terraform_state.py b/migrations/versions/665e340dbe09_add_terraform_state.py
new file mode 100644
index 0000000..efd1247
--- /dev/null
+++ b/migrations/versions/665e340dbe09_add_terraform_state.py
@@ -0,0 +1,28 @@
+"""add terraform state
+
+Revision ID: 665e340dbe09
+Revises: c644bb20d0e3
+Create Date: 2022-08-29 17:10:05.447985
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers, used by Alembic.
+revision = '665e340dbe09'
+down_revision = 'c644bb20d0e3'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.create_table('terraform_state',
+                    sa.Column('key', sa.String(), nullable=False),
+                    sa.Column('state', sa.String(), nullable=True),
+                    sa.Column('lock', sa.String(), nullable=True),
+                    sa.PrimaryKeyConstraint('key', name=op.f('pk_terraform_state'))
+                    )
+
+
+def downgrade():
+    op.drop_table('terraform_state')