Writing to the container execution log

Written by

Yandex Cloud

Updated at July 1, 2026

View in Markdown

Structured logs
- Applications and Dockerfile examples

Note

Logging is not free of charge. For more information, see Yandex Cloud Logging pricing.

Management console

CLI

Terraform

API

In the management console, select the folder with your container.
Navigate to Serverless Containers.
Select the container you want to configure logging for.
Navigate to the Editor tab.
Under Logging:
1. Enable Write logs.
2. In the Destination field, select:
  - Folder: To write logs to the default log group for the folder containing the container.
  - Log group: To write logs to a custom log group.
    
    Select the log group to write logs to or create a new one.
3. Optionally, select the minimum logging level.
At the top of the page, click Create revision.

If you set the minimum logging level, the execution log will contain logs of this level or higher. With no minimum logging level set, all container logs will be written to the execution log.

If you do not have the Yandex Cloud CLI yet, install and initialize it.

The folder used by default is the one specified when creating the CLI profile. To change the default folder, use the yc config set folder-id <folder_ID> command. You can also specify a different folder for any command using --folder-name or --folder-id. If you access a resource by its name, the search will be limited to the default folder. If you access a resource by its ID, the search will be global, i.e., through all folders based on access permissions.

Logging destination

If no custom log group is specified in the container revision settings or logging remains enabled, the container automatically writes all logs to the default log group of the folder it resides in.

To write logs to another folder's default log group, provide that folder's ID in the --log-folder-id parameter when creating a container revision. The account used to run the command must have the logging.editor role or higher for the folder.

To write logs a custom log group, provide that log group's ID in the --log-group-id parameter when creating a container revision. The log group may reside in a different folder. The account used to run the command must have the logging.editor role or higher for that folder.

Minimum logging level

To set the minimum logging level, specify it in the --min-log-level parameter when creating a container revision.

If you set the minimum logging level, the execution log will contain logs of this level or higher. With no minimum logging level set, all container logs will be written to the execution log.

Disabling logging

To disable logging, specify the --no-logging parameter when creating a container revision.

Command example

To write logs to a custom log group, run this command:

yc serverless container revision deploy \
  --container-id <container_ID> \
  --image <Docker_image_URL> \
  --service-account-id <service_account_ID> \
  --log-folder-id <folder_ID> \
  --min-log-level <minimum_logging_level>

Where:

--container-id: Container ID. To find out the ID, get the list of containers.
--image: Docker image URL.
--service-account-id: ID of the service account with Docker image pull permissions.
--log-group-id: ID of the log group to write logs to.
--min-log-level: Minimum logging level. This is an optional setting.

Result:

done (5s)
id: bba9vrtrjlld********
container_id: bbanb9mvu1dl********
created_at: "2024-05-08T07:22:45.378Z"
image:
  image_url: cr.yandex/crprip91p1q9********/ubuntu:hello
  image_digest: sha256:aa55c46fba9b14b8d8de16e2f8a07d716edfb1dbbb9433b827214ad2********
resources:
  memory: "1073741824"
  cores: "1"
  core_fraction: "100"
execution_timeout: 3s
service_account_id: ajeh91ebakk1********
status: ACTIVE
log_options:
  log_group_id: e23824sf51g5********
  min_level: ERROR

With Terraform, you can quickly create a cloud infrastructure in Yandex Cloud and manage it using configuration files. These files store the infrastructure description written in HashiCorp Configuration Language (HCL). If you change the configuration files, Terraform automatically detects which part of your configuration is already deployed, and what should be added or removed.

Terraform is distributed under the Business Source License. The Yandex Cloud provider for Terraform is distributed under the MPL-2.0 license.

For more information about the provider resources, see the relevant documentation on the Terraform website or its mirror.

If you do not have Terraform yet, install it and configure the Yandex Cloud provider.

To manage infrastructure using Terraform under a service account or user accounts (a Yandex account, a federated account, or a local user), authenticate using the appropriate method.

Logging destination

If no custom log group is specified in the container revision settings or logging remains enabled, the container automatically writes all logs to the default log group of the folder it resides in.

To write logs to another folder's default log group, provide that folder's ID under log_options in the folder_id parameter when creating a container revision. The account used to run the command must have the logging.editor role or higher for the folder.

To write logs a custom log group, provide that log group's ID under log_options in the log_group_id parameter when creating a container revision. The log group may reside in a different folder. The account used to run the command must have the logging.editor role or higher for that folder.

Open the Terraform configuration file and add the log_options section to the yandex_serverless_container resource description:

Here is an example of the configuration file structure:
```
resource "yandex_serverless_container" "<container_name>" {
  name               = "<container_name>"
  service_account_id = "<service_account_ID>"
  memory             = <RAM_amount>
  image {
    url = "<Docker_image_URL>"
  }
  log_options {
    folder_id = "<folder_ID>"
    min_level = "<minimum_logging_level>"
  }
}
```
Where:
- name: Container name.
- service_account_id: ID of the service account with Docker image pull permissions.
- memory: Required memory. The default value is 128 MB.
- image: Docker image settings:
  - url: Docker image URL.
- log_options: Logging settings:
  - folder_id: Folder ID.
  - min_level: Minimum logging level. This is an optional setting.
For more information about yandex_serverless_container properties, see this provider guide.
Create the resources:
1. In the terminal, navigate to the configuration file directory.
2. Make sure the configuration is correct using this command:
```
terraform validate
```
  If the configuration is valid, you will get this message:
```
Success! The configuration is valid.
```
3. Run this command:
```
terraform plan
```
  You will see a list of resources and their properties. No changes will be made at this step. Terraform will show any errors in the configuration.
4. Apply the configuration changes:
```
terraform apply
```
5. Type yes and press Enter to confirm the changes.

To write logs to the container execution log, use the deployRevision REST API method for the Container resource or the ContainerService/DeployRevision gRPC API call.

Structured logs

Apart from text, you can write structured logs to the standard output (stdout) and standard error output (stderr).

Applications and Dockerfile examples

Node.js

Python

index.js

const winston = require('winston');
const express = require('express');

const logger = winston.createLogger({
    level: 'debug',
    format: winston.format.json(),
    transports: [new winston.transports.Console()],
});

const app = express();
app.use(express.urlencoded({ extended: true }));
app.use(express.json());

app.get("/", (req, res) => {
    logger.info({"message": "My log message", "my-key": "my-value"})
    return res.send("Hello, world!");
});

app.listen(process.env.PORT);

Dockerfile

FROM node:16-slim

WORKDIR /app
RUN npm install winston express
COPY ./index.js .

CMD [ "node", "index.js" ]

requirements.txt

python-json-logger==2.0.4
sanic==22.12.0

index.py

import logging
import os

from pythonjsonlogger import jsonlogger
from sanic import Sanic
from sanic.response import text


class YcLoggingFormatter(jsonlogger.JsonFormatter):
    def add_fields(self, log_record, record, message_dict):
        super(YcLoggingFormatter, self).add_fields(log_record, record, message_dict)
        log_record['logger'] = record.name
        log_record['level'] = str.replace(str.replace(record.levelname, "WARNING", "WARN"), "CRITICAL", "FATAL")


app = Sanic(__name__)

logHandler = logging.StreamHandler()
logHandler.setFormatter(YcLoggingFormatter('%(message)s %(level)s %(logger)s'))

logger = logging.getLogger('MyLogger')
logger.propagate = False
logger.addHandler(logHandler)
logger.setLevel(logging.DEBUG)


@app.route("/")
async def hello(request):
    logger.info("My log message", extra={"my-key": "my-value"})
    return text("Hello, world!", status=200)


if __name__ == "__main__":
    app.run(host='0.0.0.0', port=int(os.environ['PORT']), motd=False, access_log=False)

Dockerfile

FROM python:3.10-slim

WORKDIR /app
COPY ./index.py .
COPY ./requirements.txt .
RUN pip install --no-cache-dir --prefer-binary --requirement=./requirements.txt

CMD [ "python", "index.py" ]

index.go

package main

import (
    "go.uber.org/zap"
    "net/http"
    "os"
)

func main() {
    zapConfig := zap.NewProductionConfig()
    zapConfig.DisableCaller = true
    zapConfig.Level.SetLevel(zap.DebugLevel)
    logger, _ := zapConfig.Build()

    portStr := os.Getenv("PORT")
    http.Handle("/", handler{logger})
    http.ListenAndServe(":"+portStr, nil)
}

type handler struct {
    logger *zap.Logger
}

func (h handler) ServeHTTP(writer http.ResponseWriter, _ *http.Request) {
    h.logger.Info(
        "My log message",
        zap.String("my-key", "my-value"),
    )

    writer.WriteHeader(200)
    _, _ = writer.Write([]byte("Hello, world!"))
}

Dockerfile

FROM golang:latest AS build

WORKDIR /app
ADD index.go .
ADD go.mod .
ADD go.sum .
RUN go build -a -tags netgo -ldflags '-w -extldflags "-static"' -o server-app *.go

FROM scratch
COPY --from=build /app/server-app /server-app

ENTRYPOINT ["/server-app"]

Writing to the container execution log

Logging destination

Minimum logging level

Disabling logging

Command example

Logging destination

Minimum logging level

Disabling logging

Example

Structured logs

Applications and Dockerfile examples

Was the article helpful?

Writing to the container execution log

Logging destinationLogging destination

Minimum logging levelMinimum logging level

Disabling loggingDisabling logging

Command exampleCommand example

Logging destinationLogging destination

Minimum logging levelMinimum logging level

Disabling loggingDisabling logging

ExampleExample

Structured logsStructured logs

Applications and Dockerfile examplesApplications and Dockerfile examples

Was the article helpful?

Logging destination

Minimum logging level

Disabling logging

Command example

Logging destination

Minimum logging level

Disabling logging

Example

Structured logs

Applications and Dockerfile examples