add alembic and store metrics at db

.dockerignore

@@ -0,0 +1 @@
+alembic/postgres_data

.gitignore

@@ -0,0 +1,2 @@
+*.pyc
+alembic/postgres_data

Dockerfile

@@ -3,6 +3,9 @@ FROM python:3-alpine
 COPY ./requirements.txt /app/requirements.txt
 RUN pip install -r /app/requirements.txt
 
-COPY ./src /app
+WORKDIR /app
+COPY ./alembic /app/alembic
+COPY ./alembic.ini /app/
+COPY ./src /app/src
 
-ENTRYPOINT fastapi run
+ENTRYPOINT fastapi run src/main.py

alembic.ini

@@ -0,0 +1,149 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts.
+# this is typically a path given in POSIX (e.g. forward slashes)
+# format, relative to the token %(here)s which refers to the location of this
+# ini file
+script_location = %(here)s/alembic
+
+# template used to generate migration file names; The default value is %%(rev)s_%%(slug)s
+# Uncomment the line below if you want the files to be prepended with date and time
+# see https://alembic.sqlalchemy.org/en/latest/tutorial.html#editing-the-ini-file
+# for all available tokens
+# file_template = %%(year)d_%%(month).2d_%%(day).2d_%%(hour).2d%%(minute).2d-%%(rev)s_%%(slug)s
+# Or organize into date-based subdirectories (requires recursive_version_locations = true)
+# file_template = %%(year)d/%%(month).2d/%%(day).2d_%%(hour).2d%%(minute).2d_%%(second).2d_%%(rev)s_%%(slug)s
+
+# sys.path path, will be prepended to sys.path if present.
+# defaults to the current working directory.  for multiple paths, the path separator
+# is defined by "path_separator" below.
+prepend_sys_path = .
+
+
+# timezone to use when rendering the date within the migration file
+# as well as the filename.
+# If specified, requires the tzdata library which can be installed by adding
+# `alembic[tz]` to the pip requirements.
+# string value is passed to ZoneInfo()
+# leave blank for localtime
+# timezone =
+
+# max length of characters to apply to the "slug" field
+# truncate_slug_length = 40
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+# set to 'true' to allow .pyc and .pyo files without
+# a source .py file to be detected as revisions in the
+# versions/ directory
+# sourceless = false
+
+# version location specification; This defaults
+# to <script_location>/versions.  When using multiple version
+# directories, initial revisions must be specified with --version-path.
+# The path separator used here should be the separator specified by "path_separator"
+# below.
+# version_locations = %(here)s/bar:%(here)s/bat:%(here)s/alembic/versions
+
+# path_separator; This indicates what character is used to split lists of file
+# paths, including version_locations and prepend_sys_path within configparser
+# files such as alembic.ini.
+# The default rendered in new alembic.ini files is "os", which uses os.pathsep
+# to provide os-dependent path splitting.
+#
+# Note that in order to support legacy alembic.ini files, this default does NOT
+# take place if path_separator is not present in alembic.ini.  If this
+# option is omitted entirely, fallback logic is as follows:
+#
+# 1. Parsing of the version_locations option falls back to using the legacy
+#    "version_path_separator" key, which if absent then falls back to the legacy
+#    behavior of splitting on spaces and/or commas.
+# 2. Parsing of the prepend_sys_path option falls back to the legacy
+#    behavior of splitting on spaces, commas, or colons.
+#
+# Valid values for path_separator are:
+#
+# path_separator = :
+# path_separator = ;
+# path_separator = space
+# path_separator = newline
+#
+# Use os.pathsep. Default configuration used for new projects.
+path_separator = os
+
+# set to 'true' to search source files recursively
+# in each "version_locations" directory
+# new in Alembic version 1.10
+# recursive_version_locations = false
+
+# the output encoding used when revision files
+# are written from script.py.mako
+# output_encoding = utf-8
+
+# database URL.  This is consumed by the user-maintained env.py script only.
+# other means of configuring database URLs may be customized within the env.py
+# file.
+sqlalchemy.url = postgresql+psycopg2://postgres:postgres@127.0.0.1/postgres
+
+
+[post_write_hooks]
+# post_write_hooks defines scripts or Python functions that are run
+# on newly generated revision scripts.  See the documentation for further
+# detail and examples
+
+# format using "black" - use the console_scripts runner, against the "black" entrypoint
+# hooks = black
+# black.type = console_scripts
+# black.entrypoint = black
+# black.options = -l 79 REVISION_SCRIPT_FILENAME
+
+# lint with attempts to fix using "ruff" - use the module runner, against the "ruff" module
+# hooks = ruff
+# ruff.type = module
+# ruff.module = ruff
+# ruff.options = check --fix REVISION_SCRIPT_FILENAME
+
+# Alternatively, use the exec runner to execute a binary found on your PATH
+# hooks = ruff
+# ruff.type = exec
+# ruff.executable = ruff
+# ruff.options = check --fix REVISION_SCRIPT_FILENAME
+
+# Logging configuration.  This is also consumed by the user-maintained
+# env.py script only.
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARNING
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARNING
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S

alembic/README

@@ -0,0 +1 @@
+Generic single-database configuration.

alembic/compose.yaml

@@ -0,0 +1,12 @@
+version: "3.9"
+services:
+  db:
+    image: postgres
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_DB: postgres
+    volumes:
+      - ./postgres_data:/var/lib/postgresql
+    ports:
+      - "5432:5432"

alembic/env.py

@@ -0,0 +1,81 @@
+import os
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config, pool
+
+from alembic import context
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+# from myapp import mymodel
+# target_metadata = mymodel.Base.metadata
+from src.models import BaseModel
+
+target_metadata = BaseModel.metadata
+
+# other values from the config, defined by the needs of env.py,
+# can be acquired:
+# my_important_option = config.get_main_option("my_important_option")
+# ... etc.
+
+if os.getenv("DATABASE_URL") is not None:
+    config.set_main_option("sqlalchemy.url", os.getenv("DATABASE_URL"))
+
+
+def run_migrations_offline() -> None:
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL
+    and not an Engine, though an Engine is acceptable
+    here as well.  By skipping the Engine creation
+    we don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+
+    """
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online() -> None:
+    """Run migrations in 'online' mode.
+
+    In this scenario we need to create an Engine
+    and associate a connection with the context.
+
+    """
+    connectable = engine_from_config(
+        config.get_section(config.config_ini_section, {}),
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+
+    with connectable.connect() as connection:
+        context.configure(connection=connection, target_metadata=target_metadata)
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

alembic/script.py.mako

@@ -0,0 +1,28 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision: str = ${repr(up_revision)}
+down_revision: Union[str, Sequence[str], None] = ${repr(down_revision)}
+branch_labels: Union[str, Sequence[str], None] = ${repr(branch_labels)}
+depends_on: Union[str, Sequence[str], None] = ${repr(depends_on)}
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    ${downgrades if downgrades else "pass"}

alembic/versions/4000ffc08875_autogenerate_test.py

@@ -0,0 +1,37 @@
+"""autogenerate test
+
+Revision ID: 4000ffc08875
+Revises: ec51bfd7f8fe
+Create Date: 2026-02-10 11:22:01.824142
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = '4000ffc08875'
+down_revision: Union[str, Sequence[str], None] = 'ec51bfd7f8fe'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('label_usage_stats',
+    sa.Column('label', sa.String(), nullable=False),
+    sa.Column('last_used', sa.Integer(), nullable=False),
+    sa.Column('used_count', sa.Integer(), nullable=True),
+    sa.PrimaryKeyConstraint('label')
+    )
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_table('label_usage_stats')
+    # ### end Alembic commands ###

alembic/versions/ec51bfd7f8fe_initial.py

@@ -0,0 +1,28 @@
+"""initial
+
+Revision ID: ec51bfd7f8fe
+Revises: 
+Create Date: 2026-02-10 11:10:12.415722
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = 'ec51bfd7f8fe'
+down_revision: Union[str, Sequence[str], None] = None
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    pass
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    pass

k8s/app.yaml

@@ -18,7 +18,38 @@ spec:
           ports:
             - name: web
               containerPort: 8000
-
+          readinessProbe:
+            exec:
+              command: ["alembic", "check"]
+            timeoutSeconds: 5
+            periodSeconds: 5
+          env:
+            - name: DATABASE_URL
+              valueFrom:
+                secretKeyRef:
+                  name: db-secrets
+                  key: url
+---
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: fastapi-app-db-migration
+spec:
+  template:
+    spec:
+      containers:
+        - name: fastapi-app-db-migration
+          image: igit.danilkolesnikov.ru/danil/playground_app
+          command: ["alembic", "upgrade", "head"]
+          env:
+            - name: DATABASE_URL
+              valueFrom:
+                secretKeyRef:
+                  name: db-secrets
+                  key: url
+      restartPolicy: OnFailure
+  backoffLimit: 5
+  ttlSecondsAfterFinished: 1
 ---
 apiVersion: v1
 kind: Service

k8s/cnpg.yaml

@@ -0,0 +1,43 @@
+apiVersion: postgresql.cnpg.io/v1
+kind: Cluster
+metadata:
+  name: fastapi-pg
+spec:
+  instances: 1
+  superuserSecret:
+    name: cluster-example-superuser
+  bootstrap:
+    initdb:
+      database: app
+      owner: app
+      secret:
+        name: cluster-example-app-user
+  storage:
+    size: 1Gi
+
+---
+apiVersion: v1
+data:
+  password: cGFzc3dvcmQxMjMK
+  username: cG9zdGdyZXM=
+kind: Secret
+metadata:
+  name: cluster-example-superuser
+type: kubernetes.io/basic-auth
+---
+apiVersion: v1
+data:
+  password: VHhWZVE0bk44MlNTaVlIb3N3cU9VUlp2UURhTDRLcE5FbHNDRUVlOWJ3RHhNZDczS2NrSWVYelM1Y1U2TGlDMg==
+  username: YXBw
+kind: Secret
+metadata:
+  name: cluster-example-app-user
+type: kubernetes.io/basic-auth
+---
+apiVersion: v1
+kind: Secret
+metadata:
+  name: db-secrets
+type: Opaque
+data:
+  url: cG9zdGdyZXNxbCtwc3ljb3BnMjovL2FwcDpUeFZlUTRuTjgyU1NpWUhvc3dxT1VSWnZRRGFMNEtwTkVsc0NFRWU5YndEeE1kNzNLY2tJZVh6UzVjVTZMaUMyQGZhc3RhcGktcGctcncvYXBw

k8s/prometheus.yaml

@@ -1,24 +0,0 @@
-apiVersion: helm.cattle.io/v1
-kind: HelmChart
-metadata:
-  name: prometheus
-  namespace: kube-system
-spec:
-  chart: kube-prometheus-stack
-  repo: https://prometheus-community.github.io/helm-charts
-  targetNamespace: monitoring
-  createNamespace: true
-  valuesContent: |-
-    prometheus:
-      prometheusSpec:
-        # Monitor all namespaces for ServiceMonitors
-        serviceMonitorSelectorNilUsesHelmValues: false
-        serviceMonitorNamespaceSelector: {}
-
-        # Monitor all namespaces for PodMonitors
-        podMonitorSelectorNilUsesHelmValues: false
-        podMonitorNamespaceSelector: {}
-
-        # Monitor all namespaces for PrometheusRules
-        ruleSelectorNilUsesHelmValues: false
-        ruleNamespaceSelector: {}

requirements.txt

@@ -1,2 +1,49 @@
-fastapi[standard]
-prometheus-fastapi-instrumentator
+alembic==1.18.3
+annotated-doc==0.0.4
+annotated-types==0.7.0
+anyio==4.12.1
+certifi==2026.1.4
+click==8.3.1
+dnspython==2.8.0
+email-validator==2.3.0
+fastapi==0.128.2
+fastapi-cli==0.0.20
+fastapi-cloud-cli==0.11.0
+fastar==0.8.0
+greenlet==3.3.1
+h11==0.16.0
+httpcore==1.0.9
+httptools==0.7.1
+httpx==0.28.1
+idna==3.11
+Jinja2==3.1.6
+Mako==1.3.10
+markdown-it-py==4.0.0
+MarkupSafe==3.0.3
+mdurl==0.1.2
+prometheus-fastapi-instrumentator==7.1.0
+prometheus_client==0.24.1
+psycopg2-binary==2.9.11
+pydantic==2.12.5
+pydantic-extra-types==2.11.0
+pydantic-settings==2.12.0
+pydantic_core==2.41.5
+Pygments==2.19.2
+python-dotenv==1.2.1
+python-multipart==0.0.22
+PyYAML==6.0.3
+rich==14.3.2
+rich-toolkit==0.18.1
+rignore==0.7.6
+sentry-sdk==2.52.0
+shellingham==1.5.4
+SQLAlchemy==2.0.46
+starlette==0.50.0
+typer==0.21.1
+typing-inspection==0.4.2
+typing_extensions==4.15.0
+urllib3==2.6.3
+uvicorn==0.40.0
+uvloop==0.22.1
+watchfiles==1.1.1
+websockets==16.0

skaffold.yaml

@@ -10,6 +10,7 @@ build:
 manifests:
   rawYaml:
     - k8s/app.yaml
+    - k8s/cnpg.yaml
 
 portForward:
   - resourceType: Service

src/main.py

@@ -1,17 +1,24 @@
+import socket
 from typing import Callable
 
 from fastapi import FastAPI
-from prometheus_client import Counter
+from prometheus_client import Gauge
 from prometheus_fastapi_instrumentator import Instrumentator
 from prometheus_fastapi_instrumentator.metrics import Info
+from sqlalchemy.orm.session import Session
 
-REQUEST_COUNT = Counter(
+import models
+
+REQUEST_COUNT = Gauge(
     "label_counter", "How many times called with specific label", labelnames=("label",)
 )
 
 
 def http_requested_languages_total() -> Callable[[Info], None]:
-    def instrumentation(info: Info) -> None: ...
+    def instrumentation(info: Info) -> None:
+        with Session(models.engine) as session:
+            for label_info in models.LabelUsageRecord.get_all_stats(session=session):
+                REQUEST_COUNT.labels(label_info.label).set(label_info.used_count)
 
     return instrumentation
 
@@ -23,5 +30,13 @@ Instrumentator().add(http_requested_languages_total()).instrument(app).expose(ap
 @app.get("/")
 async def read_root(label=None):
     if label:
-        REQUEST_COUNT.labels(label).inc()
-    return {"Hello": "World"}
+        with Session(models.engine) as session:
+            models.LabelUsageRecord.update_label_usage_record(label, session=session)
+            session.commit()
+    return {"Hello": "World", "from": socket.gethostname()}
+
+
+@app.get("/test")
+async def read_label(label):
+    with Session(models.engine) as session:
+        return models.LabelUsageRecord.get_label_usage_record(label, session=session)

src/models.py

@@ -0,0 +1,43 @@
+import os
+import time
+from typing import List
+
+from sqlalchemy import Boolean, Column, Integer, String, create_engine, select
+from sqlalchemy.orm import DeclarativeBase
+from sqlalchemy.orm.session import Session
+
+engine = create_engine(os.getenv("DATABASE_URL"), echo=True)
+
+
+class BaseModel(DeclarativeBase):
+    pass
+
+
+class LabelUsageRecord(BaseModel):
+    __tablename__ = "label_usage_stats"
+
+    label = Column(String, primary_key=True)
+    last_used = Column(Integer, nullable=False)
+    used_count = Column(Integer)
+
+    @staticmethod
+    def get_label_usage_record(label, session: Session):
+        stmt = select(LabelUsageRecord).where(LabelUsageRecord.label == label)
+        result = session.scalar(stmt)
+
+        if not result:
+            result = LabelUsageRecord(label=label, last_used=0, used_count=0)
+
+        return result
+
+    @staticmethod
+    def update_label_usage_record(label: str, session: Session):
+        usage = LabelUsageRecord.get_label_usage_record(label, session=session)
+        usage.used_count += 1
+        usage.last_used = int(time.time())
+        session.add(usage)
+
+    @staticmethod
+    def get_all_stats(session: Session) -> List[LabelUsageRecord]:
+        stmt = select(LabelUsageRecord)
+        return session.scalars(stmt)