Docker environment

swh-environment/docker/ contains Dockerfiles to run a small Software Heritage instance on development machines. The end goal is to smooth the contributors/developers workflow. Focus on coding, not configuring!

Warning

Running a Software Heritage instance on your machine can consume quite a bit of resources: if you play a bit too hard (e.g., if you try to list all GitHub repositories with the corresponding lister), you may fill your hard drive, and consume a lot of CPU, memory and network bandwidth.

Dependencies

This uses docker with docker-compose, so ensure you have a working docker environment and docker-compose is installed.

We recommend using the latest version of docker, so please read https://docs.docker.com/install/linux/docker-ce/debian/ for more details on how to install docker on your machine.

On a debian system, docker-compose can be installed from Debian repositories:

~$ sudo apt install docker-compose

Quick start

First, change to the docker dir if you aren’t there yet:

~$ cd swh-environment/docker

Then, start containers:

~/swh-environment/docker$ docker-compose up -d
[...]
Creating docker_amqp_1               ... done
Creating docker_zookeeper_1          ... done
Creating docker_kafka_1              ... done
Creating docker_flower_1             ... done
Creating docker_swh-scheduler-db_1   ... done
[...]

This will build docker images and run them. Check everything is running fine with:

~/swh-environment/docker$ docker-compose ps
                         Name                                       Command               State                                      Ports
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
docker_amqp_1                                    docker-entrypoint.sh rabbi ...   Up      15671/tcp, 0.0.0.0:5018->15672/tcp, 25672/tcp, 4369/tcp, 5671/tcp, 5672/tcp
docker_flower_1                                  flower --broker=amqp://gue ...   Up      0.0.0.0:5555->5555/tcp
docker_kafka_1                                   start-kafka.sh                   Up      0.0.0.0:9092->9092/tcp
docker_swh-deposit-db_1                          docker-entrypoint.sh postgres    Up      5432/tcp
docker_swh-deposit_1                             /entrypoint.sh                   Up      0.0.0.0:5006->5006/tcp
[...]

The startup of some containers may fail the first time for dependency-related problems. If some containers failed to start, just run the docker-compose up -d command again.

If a container really refuses to start properly, you can check why using the docker-compose logs command. For example:

~/swh-environment/docker$ docker-compose logs swh-lister
Attaching to docker_swh-lister_1
[...]
swh-lister_1                      | Processing /src/swh-scheduler
swh-lister_1                      | Could not install packages due to an EnvironmentError: [('/src/swh-scheduler/.hypothesis/unicodedata/8.0.0/charmap.json.gz', '/tmp/pip-req-build-pm7nsax3/.hypothesis/unicodedata/8.0.0/charmap.json.gz', "[Errno 13] Permission denied: '/src/swh-scheduler/.hypothesis/unicodedata/8.0.0/charmap.json.gz'")]
swh-lister_1                      |

Once all containers are running, you can use the web interface by opening http://localhost:5080/ in your web browser.

At this point, the archive is empty and needs to be filled with some content. To do so, you can create tasks that will scrape a forge. For example, to inject the code from the https://0xacab.org gitlab forge:

~/swh-environment/docker$ docker-compose exec swh-scheduler \
    swh scheduler task add list-gitlab-full \
      -p oneshot url=https://0xacab.org/api/v4

Created 1 tasks

Task 1
  Next run: just now (2018-12-19 14:58:49+00:00)
  Interval: 90 days, 0:00:00
  Type: list-gitlab-full
  Policy: oneshot
  Args:
  Keyword args:
    url=https://0xacab.org/api/v4

This task will scrape the forge’s project list and register origins to the scheduler. This takes at most a couple of minutes.

Then, you must tell the scheduler to create loading tasks for these origins. For example, to create tasks for 100 of these origins:

~/swh-environment/docker$ docker-compose exec swh-scheduler \
    swh scheduler origin schedule-next git 100

This will take a bit of time to complete.

To increase the speed at which git repositories are imported, you can spawn more swh-loader-git workers:

~/swh-environment/docker$ docker-compose exec swh-scheduler \
    celery status
listers@50ac2185c6c9: OK
loader@b164f9055637: OK
indexer@33bc6067a5b8: OK
vault@c9fef1bbfdc1: OK

4 nodes online.
~/swh-environment/docker$ docker-compose exec swh-scheduler \
    celery control pool_grow 3 -d loader@b164f9055637
-> loader@b164f9055637: OK
        pool will grow
~/swh-environment/docker$ docker-compose exec swh-scheduler \
    celery inspect -d loader@b164f9055637 stats | grep prefetch_count
       "prefetch_count": 4

Now there are 4 workers ingesting git repositories. You can also increase the number of swh-loader-git containers:

~/swh-environment/docker$ docker-compose up -d --scale swh-loader=4
[...]
Creating docker_swh-loader_2        ... done
Creating docker_swh-loader_3        ... done
Creating docker_swh-loader_4        ... done

Updating the docker image

All containers started by docker-compose are bound to a docker image named swh/stack including all the software components of Software Heritage. When new versions of these components are released, the docker image will not be automatically updated. In order to update all Software Heritage components to their latest version, the docker image needs to be explicitly rebuilt by issuing the following command from within the docker directory:

~/swh-environment/docker$ docker build --no-cache -t swh/stack .

Details

This runs the following services on their respectively standard ports, all of the following services are configured to communicate with each other:

  • swh-storage-db: a softwareheritage instance db that stores the Merkle DAG,

  • swh-objstorage: Content-addressable object storage,

  • swh-storage: Abstraction layer over the archive, allowing to access all stored source code artifacts as well as their metadata,

  • swh-web: the Software Heritage web user interface (with a default “admin” account with password “admin”),

  • swh-scheduler: the API service as well as 2 utilities, the runner and the listener,

  • swh-lister: celery workers dedicated to running lister tasks,

  • swh-loaders: celery workers dedicated to importing/updating source code content (VCS repos, source packages, etc.),

  • swh-journal: Persistent logger of changes to the archive, with publish-subscribe support.

That means you can start doing the ingestion using those services using the same setup described in the getting-started starting directly at https://docs.softwareheritage.org/devel/getting-started.html#step-4-ingest-repositories

Exposed Ports

Several services have their listening ports exposed on the host:

  • amqp: 5072

  • kafka: 5092

  • nginx: 5080

And for SWH services:

  • scheduler API: 5008

  • storage API: 5002

  • object storage API: 5003

  • indexer API: 5007

  • web app: 5004

  • deposit app: 5006

Beware that these ports are not the same as the ports used from within the docker network. This means that the same command executed from the host or from a docker container will not use the same urls to access services. For example, to use the celery utility from the host, you may type:

~/swh-environment/docker$ CELERY_BROKER_URL=amqp://:5072// celery status
loader@61704103668c: OK
[...]

To run the same command from within a container:

~/swh-environment/docker$ docker-compose exec swh-scheduler celery status
loader@61704103668c: OK
[...]

Managing tasks

One of the main components of the Software Heritage platform is the task system. These are used to manage everything related to background process, like discovering new git repositories to import, ingesting them, checking a known repository is up to date, etc.

The task system is based on Celery but uses a custom database-based scheduler.

So when we refer to the term ‘task’, it may designate either a Celery task or a SWH one (ie. the entity in the database). When we refer to simply a “task” in the documentation, it designates the SWH task.

When a SWH task is ready to be executed, a Celery task is created to handle the actual SWH task’s job. Note that not all Celery tasks are directly linked to a SWH task (some SWH tasks are implemented using a Celery task that spawns Celery subtasks).

A (SWH) task can be recurring or oneshot. oneshot tasks are only executed once, whereas recurring are regularly executed. The scheduling configuration of these recurring tasks can be set via the fields current_interval and priority (can be ‘high’, ‘normal’ or ‘low’) of the task database entity.

Inserting a new lister task

To list the content of a source code provider like github or a Debian distribution, you may add a new task for this.

This task will (generally) scrape a web page or use a public API to identify the list of published software artefacts (git repos, debian source packages, etc.)

Then, for each repository, a new task will be created to ingest this repository and keep it up to date.

For example, to add a (one shot) task that will list git repos on the 0xacab.org gitlab instance, one can do (from this git repository):

~/swh-environment/docker$ docker-compose exec swh-scheduler \
    swh scheduler task add list-gitlab-full \
      -p oneshot url=https://0xacab.org/api/v4

Created 1 tasks

Task 12
  Next run: just now (2018-12-19 14:58:49+00:00)
  Interval: 90 days, 0:00:00
  Type: list-gitlab-full
  Policy: oneshot
  Args:
  Keyword args:
    url=https://0xacab.org/api/v4

This will insert a new task in the scheduler. To list existing tasks for a given task type:

~/swh-environment/docker$ docker-compose exec swh-scheduler \
  swh scheduler task list-pending list-gitlab-full

Found 1 list-gitlab-full tasks

Task 12
  Next run: 2 minutes ago (2018-12-19 14:58:49+00:00)
  Interval: 90 days, 0:00:00
  Type: list-gitlab-full
  Policy: oneshot
  Args:
  Keyword args:
    url=https://0xacab.org/api/v4

To list all existing task types:

~/swh-environment/docker$ docker-compose exec swh-scheduler \
  swh scheduler task-type list

Known task types:
load-svn-from-archive:
  Loading svn repositories from svn dump
load-svn:
  Create dump of a remote svn repository, mount it and load it
load-deposit:
  Loading deposit archive into swh through swh-loader-tar
check-deposit:
  Pre-checking deposit step before loading into swh archive
cook-vault-bundle:
  Cook a Vault bundle
load-hg:
  Loading mercurial repository swh-loader-mercurial
load-hg-from-archive:
  Loading archive mercurial repository swh-loader-mercurial
load-git:
  Update an origin of type git
list-github-incremental:
  Incrementally list GitHub
list-github-full:
  Full update of GitHub repos list
list-debian-distribution:
  List a Debian distribution
list-gitlab-incremental:
  Incrementally list a Gitlab instance
list-gitlab-full:
  Full update of a Gitlab instance's repos list
list-pypi:
  Full pypi lister
load-pypi:
  Load Pypi origin
index-mimetype:
  Mimetype indexer task
index-mimetype-for-range:
  Mimetype Range indexer task
index-fossology-license:
  Fossology license indexer task
index-fossology-license-for-range:
  Fossology license range indexer task
index-origin-head:
  Origin Head indexer task
index-revision-metadata:
  Revision Metadata indexer task
index-origin-metadata:
  Origin Metadata indexer task

Monitoring activity

You can monitor the workers activity by connecting to the RabbitMQ console on http://localhost:5080/rabbitmq or the grafana dashboard on http://localhost:5080/grafana.

If you cannot see any task being executed, check the logs of the swh-scheduler-runner service (here is a failure example due to the debian lister task not being properly registered on the swh-scheduler-runner service):

~/swh-environment/docker$ docker-compose logs --tail=10 swh-scheduler-runner
Attaching to docker_swh-scheduler-runner_1
swh-scheduler-runner_1    |     "__main__", mod_spec)
swh-scheduler-runner_1    |   File "/usr/local/lib/python3.7/runpy.py", line 85, in _run_code
swh-scheduler-runner_1    |     exec(code, run_globals)
swh-scheduler-runner_1    |   File "/usr/local/lib/python3.7/site-packages/swh/scheduler/celery_backend/runner.py", line 107, in <module>
swh-scheduler-runner_1    |     run_ready_tasks(main_backend, main_app)
swh-scheduler-runner_1    |   File "/usr/local/lib/python3.7/site-packages/swh/scheduler/celery_backend/runner.py", line 81, in run_ready_tasks
swh-scheduler-runner_1    |     task_types[task['type']]['backend_name']
swh-scheduler-runner_1    |   File "/usr/local/lib/python3.7/site-packages/celery/app/registry.py", line 21, in __missing__
swh-scheduler-runner_1    |     raise self.NotRegistered(key)
swh-scheduler-runner_1    | celery.exceptions.NotRegistered: 'swh.lister.debian.tasks.DebianListerTask'

Using docker setup development and integration testing

If you hack the code of one or more archive components with a virtual env based setup as described in the [[https://docs.softwareheritage.org/devel/developer-setup.html|developer setup guide]], you may want to test your modifications in a working Software Heritage instance. The simplest way to achieve this is to use this docker-based environment.

If you haven’t followed the [[https://docs.softwareheritage.org/devel/developer-setup.html|developer setup guide]], you must clone the the [swh-environment] repo in your swh-environment directory:

~/swh-environment$ git clone https://forge.softwareheritage.org/source/swh-environment.git .

Note the . at the end of this command: we want the git repository to be cloned directly in the ~/swh-environment directory, not in a sub directory. Also note that if you haven’t done it yet and you want to hack the source code of one or more Software Heritage packages, you really should read the [[https://docs.softwareheritage.org/devel/developer-setup.html|developer setup guide]].

From there, we will checkout or update all the swh packages:

~/swh-environment$ ./bin/update

Install a swh package from sources in a container

It is possible to run a docker container with some swh packages installed from sources instead of using the latest published packages from pypi. To do this you must write a docker-compose override file (docker-compose.override.yml). An example is given in the docker-compose.override.yml.example file:

version: '2'

services:
  swh-objstorage:
    volumes:
      - "$HOME/swh-environment/swh-objstorage:/src/swh-objstorage"

The file named docker-compose.override.yml will automatically be loaded by docker-compose.

This example shows the simplest case of the swh-objstorage package: you just have to mount it in the container in /src and the entrypoint will ensure every swh-* package found in /src/ is installed (using pip install -e so you can easily hack your code). If the application you play with has autoreload support, there is no need to restart the impacted container.)

Using locally installed swh tools with docker

In all examples above, we have executed swh commands from within a running container. Now we also have these swh commands locally available in our virtual env, we can use them to interact with swh services running in docker containers.

For this, we just need to configure a few environment variables. First, ensure your Software Heritage virtualenv is activated (here, using virtualenvwrapper):

~$ workon swh
(swh) ~/swh-environment$ export SWH_SCHEDULER_URL=http://127.0.0.1:5008/
(swh) ~/swh-environment$ export CELERY_BROKER_URL=amqp://127.0.0.1:5072/

Now we can use the celery command directly to control the celery system running in the docker environment:

(swh) ~/swh-environment$ celery status
vault@c9fef1bbfdc1: OK
listers@ba66f18e7d02: OK
indexer@cb14c33cbbfb: OK
loader@61704103668c: OK

4 nodes online.
(swh) ~/swh-environment$ celery control -d loader@61704103668c pool_grow 3

And we can use the swh-scheduler command all the same:

(swh) ~/swh-environment$ swh scheduler task-type list
Known task types:
index-fossology-license:
  Fossology license indexer task
index-mimetype:
  Mimetype indexer task
[...]

Make your life a bit easier

When you use virtualenvwrapper, you can add postactivation commands:

(swh) ~/swh-environment$ cat >>$VIRTUAL_ENV/bin/postactivate <<'EOF'
# unfortunately, the interface cmd for the click autocompletion
# depends on the shell
# https://click.palletsprojects.com/en/7.x/bashcomplete/#activation

shell=$(basename $SHELL)
case "$shell" in
    "zsh")
        autocomplete_cmd=source_zsh
        ;;
    *)
        autocomplete_cmd=source
        ;;
esac

eval "$(_SWH_COMPLETE=$autocomplete_cmd swh)"
export SWH_SCHEDULER_URL=http://127.0.0.1:5008/
export CELERY_BROKER_URL=amqp://127.0.0.1:5072/
export COMPOSE_FILE=~/swh-environment/docker/docker-compose.yml:~/swh-environment/docker/docker-compose.override.yml
alias doco=docker-compose

EOF

This postactivate script does:

  • install a shell completion handler for the swh-scheduler command,

  • preset a bunch of environment variables

    • SWH_SCHEDULER_URL so that you can just run swh scheduler against the scheduler API instance running in docker, without having to specify the endpoint URL,

    • CELERY_BROKER so you can execute the celery tool (without cli options) against the rabbitmq server running in the docker environment,

    • COMPOSE_FILE so you can run docker-compose from everywhere,

  • create an alias doco for docker-compose because this is way too long to type,

So now you can easily:

  • Start the SWH platform:

    (swh) ~/swh-environment$ doco up -d
    [...]
    
  • Check celery:

    (swh) ~/swh-environment$ celery status
    listers@50ac2185c6c9: OK
    loader@b164f9055637: OK
    indexer@33bc6067a5b8: OK
    
  • List task-types:

    (swh) ~/swh-environment$ swh scheduler task-type list
    [...]
    
  • Get more info on a task type:

    (swh) ~/swh-environment$ swh scheduler task-type list -v -t load-hg
    Known task types:
    load-hg: swh.loader.mercurial.tasks.LoadMercurial
      Loading mercurial repository swh-loader-mercurial
      interval: 1 day, 0:00:00 [1 day, 0:00:00, 1 day, 0:00:00]
      backoff_factor: 1.0
      max_queue_length: 1000
      num_retries: None
      retry_delay: None
    
  • Add a new task:

    (swh) ~/swh-environment$ swh scheduler task add load-hg \
      origin_url=https://hg.logilab.org/master/cubicweb
    Created 1 tasks
    Task 1
       Next run: just now (2019-02-06 12:36:58+00:00)
       Interval: 1 day, 0:00:00
       Type: load-hg
       Policy: recurring
       Args:
       Keyword args:
         origin_url: https://hg.logilab.org/master/cubicweb
    
  • Respawn a task:

    (swh) ~/swh-environment$ swh scheduler task respawn 1
    

Data persistence for a development setting

The default docker-compose.yml configuration is not geared towards data persistence, but application testing.

Volumes defined in associated images are anonymous and may get either unused or removed on the next docker-compose up.

One way to make sure these volumes persist is to use named volumes. The volumes may be defined as follows in a docker-compose.override.yml. Note that volume definitions are merged with other compose files based on destination path.

services:
  swh-storage-db:
    volumes:
      - "swh_storage_data:/var/lib/postgresql/data"
  swh-objstorage:
    volumes:
      - "swh_objstorage_data:/srv/softwareheritage/objects"

volumes:
  swh_storage_data:
  swh_objstorage_data:

This way, docker-compose down without the -v flag will not remove those volumes and data will persist.

Additional components

We provide some extra modularity in what components to run through additional docker-compose.*.yml files.

They are disabled by default, because they add layers of complexity and increase resource usage, while not being necessary to operate a small Software Heritage instance.

Starting a kafka-powered mirror of the storage

This repo comes with an optional docker-compose.storage-mirror.yml docker compose file that can be used to test the kafka-powered mirror mechanism for the main storage.

This can be used like:

~/swh-environment/docker$ docker-compose -f docker-compose.yml -f docker-compose.storage-mirror.yml up -d
[...]

Compared to the original compose file, this will:

  • overrides the swh-storage service to activate the kafka direct writer on swh.journal.objects prefixed topics using the swh.storage.master ID,

  • overrides the swh-web service to make it use the mirror instead of the master storage,

  • starts a db for the mirror,

  • starts a storage service based on this db,

  • starts a replayer service that runs the process that listen to kafka to keeps the mirror in sync.

When using it, you will have a setup in which the master storage is used by workers and most other services, whereas the storage mirror will be used to by the web application and should be kept in sync with the master storage by kafka.

Note that the object storage is not replicated here, only the graph storage.

Starting the backfiller

Reading from the storage the objects from within range [start-object, end-object] to the kafka topics.

(swh)$ docker-compose \
             -f docker-compose.yml \
             -f docker-compose.storage-mirror.yml \
             -f docker-compose.storage-mirror.override.yml \
             run \
             swh-journal-backfiller \
             snapshot \
             --start-object 000000 \
             --end-object 000001 \
             --dry-run

Cassandra

We are working on an alternative backend for swh-storage, based on Cassandra instead of PostgreSQL.

This can be used like:

~/swh-environment/docker$ docker-compose -f docker-compose.yml -f docker-compose.cassandra.yml up -d
[...]

This launches two Cassandra servers, and reconfigures swh-storage to use them.

Efficient counters

The web interface shows counters of the number of objects in your archive, by counting objects in the PostgreSQL or Cassandra database.

While this should not be an issue at the scale of your local Docker instance, counting objects can actually be a bottleneck at Software Heritage’s scale. So swh-storage uses heuristics, that can be either not very efficient or inaccurate.

So we have an alternative based on Redis’ HyperLogLog feature, which you can test with:

~/swh-environment/docker$ docker-compose -f docker-compose.yml -f docker-compose.counters.yml up -d
[...]

Efficient graph traversals

swh-graph is a work-in-progress alternative to swh-storage to perform large graph traversals/queries on the merkle DAG.

For example, it can be used by the vault, as it needs to query all objects in the sub-DAG of a given node.

You can use it with:

~/swh-environment/docker$ docker-compose -f docker-compose.yml -f docker-compose.graph.yml up -d

On the first start, it will run some precomputation based on all objects already in your local SWH instance; so it may take a long time if you loaded many repositories. (Expect 5 to 10s per repository.)

It does not update automatically when you load new repositories. You need to restart it every time you want to update it.

You can mount a docker volume on /srv/softwareheritage/graph to avoid recomputing this graph on every start. Then, you need to explicitly request recomputing the graph before restarts if you want to update it:

~/swh-environment/docker$ docker-compose -f docker-compose.yml -f docker-compose.graph.yml run swh-graph update
~/swh-environment/docker$ docker-compose -f docker-compose.yml -f docker-compose.graph.yml stop swh-graph
~/swh-environment/docker$ docker-compose -f docker-compose.yml -f docker-compose.graph.yml up swh-graph -d

Keycloak

If you really want to hack on swh-web’s authentication features, you will need to enable Keycloak as well, instead of the default Django-based authentication:

~/swh-environment/docker$ docker-compose -f docker-compose.yml -f docker-compose.keycloak.yml up -d
[...]

User registration in Keycloak database is available by following the Register link in the page located at http://localhost:5080/oidc/login/.

Please note that email verification is required to properly register an account. As we are in a testing environment, we use a MailHog instance as a fake SMTP server. All emails sent by Keycloak can be easily read from the MailHog Web UI located at http://localhost:8025/.

Using Sentry

All entrypoints to SWH code (CLI, gunicorn, celery, …) are, or should be, instrumented using Sentry. By default this is disabled, but if you run your own Sentry instance, you can use it.

To do so, you must get a DSN from your Sentry instance, and set it as the value of SWH_SENTRY_DSN in the file env/common_python.env. You may also set it per-service in the environment section of each services in docker-compose.override.yml.

Caveats

Running a lister task can lead to a lot of loading tasks, which can fill your hard drive pretty fast. Make sure to monitor your available storage space regularly when playing with this stack.

Also, a few containers (swh-storage, swh-xxx-db) use a volume for storing the blobs or the database files. With the default configuration provided in the docker-compose.yml file, these volumes are not persistent. So removing the containers will delete the volumes!

Also note that for the swh-objstorage, since the volume can be pretty big, the remove operation can be quite long (several minutes is not uncommon), which may mess a bit with the docker-compose command.

If you have an error message like:

Error response from daemon: removal of container 928de3110381 is already in progress

it means that you need to wait for this process to finish before being able to (re)start your docker stack again.