Tag Archives: docker

mounterbank for mocking and stubbing http services (rest+graphql+grpc)

http://www.mbtest.org/docs/api/stubs can be used to stub http(s)/tcp/smtp protocols. And has community plugins for grpc, graphql, websockets. You can configure it with imposters.ejs like below:

{
  "port": 80,
  "protocol": "http",
  "defaultResponse": {
    "statusCode": 404,
    "headers": {}
  },
  "stubs": [
    <% include stubs/service1.json %>,
    <% include stubs/service2.json %>,
    <% include stubs/service3.json %>
  ]
}

{

"port": 80,

"protocol": "http",

"defaultResponse": {

"statusCode": 404,

"headers": {}

"stubs": [

<% include stubs/service1.json %>,

<% include stubs/service2.json %>,

<% include stubs/service3.json %>

]

}

docker-compose.yml

version: "3.5"

services:
  mountebank:
    container_name: mountebank
    image: jkris/mountebank:latest
    volumes:
      - ./:/mountebank
    ports:
      - "15050:80"
    command: --configfile /mountebank/imposters.ejs --allowInjection

version: "3.5"

services:

mountebank:

container_name: mountebank

image: jkris/mountebank:latest

volumes:

- ./:/mountebank

ports:

- "15050:80"

command: --configfile /mountebank/imposters.ejs --allowInjection

Fixing docker does not want to update images

If you run docker pull, and you see an error like failed to register layer: Error processing tar file(exit status 2): fatal error: runtime: out of memory, there could be 2 reasons. Obvious one — not enough disk space for docker. You can fix it with

docker system prune -af
docker volume ls -qf dangling=true

1 2	docker system prune -af docker volume ls -qf dangling=true

WARNING: It will remove your unused resources like …

Create SQS queues on localstack container start

Put this file to your filesystem as ←anyname.sh→:

#!/usr/bin/env bash

set -euo pipefail

# enable debug
# set -x


echo "configuring sqs"
echo "==================="
LOCALSTACK_HOST=localhost
AWS_REGION=eu-central-1


# https://docs.aws.amazon.com/cli/latest/reference/sqs/create-queue.html
create_queue() {
	local QUEUE_NAME_TO_CREATE=$1
	awslocal --endpoint-url=http://${LOCALSTACK_HOST}:4566 sqs create-queue --queue-name ${QUEUE_NAME_TO_CREATE} --region ${AWS_REGION} --attributes VisibilityTimeout=30
}

create_queue "queue2"
create_queue "queue1"

#!/usr/bin/env bash

set -euo pipefail

# enable debug

# set -x

echo "configuring sqs"

echo "==================="

LOCALSTACK_HOST=localhost

AWS_REGION=eu-central-1

# https://docs.aws.amazon.com/cli/latest/reference/sqs/create-queue.html

create_queue() {

local QUEUE_NAME_TO_CREATE=$1

awslocal --endpoint-url=http://${LOCALSTACK_HOST}:4566 sqs create-queue --queue-name ${QUEUE_NAME_TO_CREATE} --region ${AWS_REGION} --attributes VisibilityTimeout=30

}

create_queue "queue2"

create_queue "queue1"

For instance, ./localstack_bootstrap/sqs_bootstrap.sh. Don’t forget to run chmod +x ./localstack_bootstrap/sqs_bootstrap.sh. Add this line to your docker-compose.yml: — ./localstack_bootstrap:/docker-entrypoint-initaws.d/. So it could look like this:

services:
  localstack:
    container_name: aws_sqs
    hostname: sqs
    image: localstack/localstack:latest
    environment:
      - AWS_DEFAULT_REGION=ap-southeast-1
      - EDGE_PORT=4566
      - SERVICES=sqs
    ports:
      - '4566:4566'
    volumes:
      - "${TMPDIR:-/tmp/localstack}:/tmp/localstack"
      - "/var/run/docker.sock:/var/run/docker.sock"
      - ./localstack_bootstrap:/docker-entrypoint-initaws.d/

services:

localstack:

container_name: aws_sqs

hostname: sqs

image: localstack/localstack:latest

environment:

- AWS_DEFAULT_REGION=ap-southeast-1

- EDGE_PORT=4566

- SERVICES=sqs

ports:

- '4566:4566'

volumes:

- "${TMPDIR:-/tmp/localstack}:/tmp/localstack"

- "/var/run/docker.sock:/var/run/docker.sock"

- ./localstack_bootstrap:/docker-entrypoint-initaws.d/

Then your queues can be reached by URLs http://localhost:4566/000000000000/queue1 and http://localhost:4566/000000000000/queue2. Further reading: https://docs.aws.amazon.com/cli/latest/reference/sqs/create-queue.html https://joerg-pfruender.github.io/software/docker/microservices/testing/2020/01/25/Localstack_in_Docker.html

Using tcpdump for k8s pods

You need wireshark to be installed on your local machine — download (more on this below). If you don’t have tcpdump installed inside the pod, you can install it with

# get pod name
kubectl get po -Lversion,cfg,infra-cfg -lapp=<pod-tag>
kubectl exec -it <pod-name> sh
# inside the pod, alpine
apk add tcpdump

# get pod name

kubectl get po -Lversion,cfg,infra-cfg -lapp=<pod-tag>

kubectl exec -it <pod-name> sh

# inside the pod, alpine

apk add tcpdump

Then, on your local machine:

kubectl exec <pod-name> -- tcpdump -i eth0 -w - | wireshark -k -i -

1	kubectl exec <pod-name> -- tcpdump -i eth0 -w - \| wireshark -k -i -

If you want to see packets in grpc/http2, you can add a rule in Wireshark. For this, click …

DOCKER_CONTENT_TRUST=1 docker run --rm --name dd-agent -p 8126:8126 -v /var/run/docker.sock:/var/run/docker.sock:ro -v /proc/:/host/proc/:ro -v /sys/fs/cgroup/:/host/sys/fs/cgroup:ro -e DD_API_KEY=REPLACE_WITH_NEW_KEY -e DD_SITE=datadoghq.eu datadog/agent

1	DOCKER_CONTENT_TRUST=1 docker run --rm --name dd-agent -p 8126:8126 -v /var/run/docker.sock:/var/run/docker.sock:ro -v /proc/:/host/proc/:ro -v /sys/fs/cgroup/:/host/sys/fs/cgroup:ro -e DD_API_KEY=REPLACE_WITH_NEW_KEY -e DD_SITE=datadoghq.eu datadog/agent

mmock for mocking microservices

It is a very easy to set up though pretty powerful tool with support for delays and handling query params. It also has a console for checking all the requests and corresponding responses matched. Here it is https://github.com/jmartin82/mmock. Below I describe a way to use it with docker-compose for local development.

XDebug inside a docker container

That’s how you can debug your php app running in a docker container.

Integration tests with testcontainers-go

Here is the go library that simplifies integration tests with docker containers — https://github.com/testcontainers/testcontainers-go. That’s how you can use it to test sql — https://github.com/testcontainers/testcontainers-go/blob/master/docs/examples/cockroachdb.md. Project documentation — https://golang.testcontainers.org/features/docker_compose/ The idea is to prepare the environment, build your app, then make requests and check the DB state.

Read logs from docker container

tail -f `docker inspect --format='{{.LogPath}}' [containername]`

1	tail -f `docker inspect --format='{{.LogPath}}' [containername]`

Postgres in docker: random «unique violation» errors

While running postgres in docker (for development, of course), from time to time I just run into errors like «Duplicate Key Value Violates Unique Constraint». I found the solution (thanks to this answer, for sure — https://stackoverflow.com/a/47089825/801426): if you have a table called «[table]», just do this

SELECT setval('[table]_id_seq', (SELECT MAX(id) FROM [table]));

1	SELECT setval('[table]_id_seq', (SELECT MAX(id) FROM [table]));