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Working with Pipeline Services

The pipelines local runner supports services since version 0.0.37 (the special docker service from version 0.0.25 is not covered by this document, see Pipelines inside Pipeline).

Introduction | Example | Validate | Trouble-Shoot | Debug

Introduction to Services in Pipelines

A service is another container that is started before the step script using host networking both for the service as well as for the pipeline step container.

The step script can then access on localhost the started service.

After the step script is run (and any optional after-script), the step container is shut down and removed; afterwards any service containers are shut down and removed.

Services are defined in the bitbucket-pipelines.yml file and then referenced by a pipeline step.

Next to running bitbucket pipelines locally with services, the pipelines runner has options for validating, trouble-shooting and debugging services.

Service Example

Here a simple service example with a redis service in a step script that pings it.

Defining a Service

A service definition in bitbucket-pipelines.yml is required to make use of the service in a pipeline step:

      image: redis:6.0.4-alpine
Pipelines YAML fragment: Definition of the redis service

The service named redis is then defined and ready to use by the step services.

Use a Service in a Pipeline Step

As now defined, the step is ready to use by the steps' services list by referencing the defined service name, here redis.

A default pipeline named redis service example as an example:

    - step:
        name: redis service example
        image: redis:alpine
          - redis-cli -h localhost ping
          - redis
Pipelines YAML fragment: Default pipeline step with the redis service

Note the services list at the very end, it has the redis entry. This tells pipelines to start it for the step.

Run the Pipeline with the Example Redis Service

That is it for the configuration, let us run it:

$ pipelines
+++ step #1

    name...........: "redis service example"
    effective-image: redis:alpine
    container......: pipelines-1.redis-service-example.default.pipelines
    container-id...: 1fd11cdf4291

+++ copying files into container...

+ redis-cli -h localhost ping
Command line example: Running the default pipeline with the redis service successfully pinging the service.

Validate Pipeline Services

To verify the services are defined and properly wired to pipeline steps, use the --show-services switch, it specifically shows the services by step and checks if services are defined:

$ pipelines --show-services
default        1       redis      redis:6.0.4-alpine
Command line example: Default pipeline first step uses the redis service defined with the redis:6.0.4-alpine image.

In case of an error, e.g. the service definition is missing or variables are not well-defined, this would be shown:

default        1       ERROR      Undefined service: "redis"
                       ERROR      variable MYSQL_RANDOM_ROOT_PASSWORD \
                                  should be a string (it is currently \
                                  defined as a boolean)
Command line examples: Services validation errors with --show-services

The --show-services option exits with zero status or non-zero in case an error was found.

Part of this service information is also available with the --show command, errors in the file are highlighted more prominently thought:

$ pipelines --show
pipelines: file parse error: variable MYSQL_RANDOM_ROOT_PASSWORD \
should be a string (it is currently defined as a boolean)
Command line example: Bogus variable with --show

Without any errors the --show option displays the information and exits:

$ pipelines --show
PIPELINE ID    STEP    IMAGE                 NAME
default        1       redis:alpine          "redis service example"
default        1       redis:6.0.4-alpine    service:redis
Command line example: Pipelines shows services for each pipeline step

Trouble-Shoot Starting Service Containers

Sometimes service containers do not start properly, the service container exits prematurely or other unintended things are happening setting up a service.

It is possible to start a pipelines service container manually to review the start sequence.

The --service <service> option

To start any defined service use the --service option with the name of the service in the definitions section.

$ pipelines --service mysql
error: database is uninitialized and password option is not specified
  You need to specify one of MYSQL_ROOT_PASSWORD, \
Command-line example: Missing variable for pipelines mysql service

Fixing the service definition (here by adding a variable to it) and running the pipelines --service mysql again, will show the service properly running by displaying the output of the service.

Press ctrl + z to suspend the process and either $ bg to send the service in the background or $ kill % which will shut down the service container.

Note: If the --keep or --error-keep option has been used to run the pipeline and the service exited in error, the stopped service container needs to be removed before --service can successfully run the service:

$ docker rm pipelines-service-mysql.pipelines

Debug Pipeline Services

As the pipelines utility is designed to run bitbucket pipelines locally, trouble-shooting and debugging pipeline services is easily possible and supported with various options re-iterating quickly locally.

Keep Service Containers with --keep

To leave service containers on the system for inspection and re- iteration, use the --keep (or --error-keep) option. The step container and all service containers are then kept and not removed:

$ pipelines --keep
+++ step #1

    name...........: "redis service example"
    effective-image: redis:alpine
+ redis-cli -h localhost ping
keeping container id 0aa93bcf3b7b
keeping service container pipelines-service-redis.pipelines
Command line example: Keeping service containers for inspection

Inspect Kept Containers with Docker

With the containers still running, service configuration problems can be reviewed, e.g. in case a service didn't start well. For example by inspecting the logs:

$ docker logs pipelines-service-redis.pipelines
1:C 01 Jun 2020 08:42:42.739 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
1:C 01 Jun 2020 08:42:42.739 # Redis version=6.0.4, bits=64, commit=00000000, modified=0, pid=1, just started
1:C 01 Jun 2020 08:42:42.739 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
1:M 01 Jun 2020 08:42:42.740 * Running mode=standalone, port=6379.
1:M 01 Jun 2020 08:42:42.740 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
1:M 01 Jun 2020 08:42:42.740 # Server initialized
1:M 01 Jun 2020 08:42:42.740 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
1:M 01 Jun 2020 08:42:42.740 # WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' as root, and add it to your /etc/rc.local in order to retain the setting after a reboot. Redis must be restarted after THP is disabled.
1:M 01 Jun 2020 08:42:42.740 * Ready to accept connections
Command line example: Reviewing logs of a pipeline service

Clean with --docker-zap

Running the pipeline again will re-use the existing step and service containers for a fast re-iteration. In case this is unwanted and a fresh run is preferred, just "zap" all kept pipeline containers:

$ pipelines --docker-zap
Command line example: Remove all pipeline containers incl. service containers

Afterwards all pipelines containers are gone and will be re-created on next pipelines run.