Azkaban CLI
Project description
A lightweight Azkaban client providing:
A command line interface to run workflows, upload projects, and more.
A simple syntax to define jobs from a single python file.
Extensions for your favorite job types.
Installation
Using pip:
$ pip install azkaban
Command line interface
Once the package is installed, we have access to the azkaban
command.
From there, without leaving our terminal, we can:
Create and delete projects on an Azkaban server:
azkaban create
Upload a project archive:
azkaban upload
Run entire workflows, or individual jobs:
azkaban run
Running azkaban --help
shows the list of options for each of these
commands.
These previous commands all take a --url
parameter used to specify the
Azkaban server (and user). In order to avoid having to do this every time, we
can also define aliases in ~/.azkabanrc
:
[foo]
url = http://url.to.foo.server:port
[bar]
url = http://url.to.bar.server
user = baruser
We can now interact directly to each of these URLs with the shorthand:
$ azkaban upload -a foo -z project.zip
This has the added benefit that we won’t have to authenticate on every upload. The session ID is cached and reused for later connections.
Syntax
For medium to large sized projects, it quickly becomes tricky to manage the
multitude of files required for each workflow. .properties
files are
helpful but still do not provide the flexibility to generate jobs
programmatically (i.e. using for
loops, etc.). This approach also
requires us to manually bundle and upload our project to the gateway every
time.
We provide here a convenient framework to define jobs from a single python file. This framework is entirely compatible with the command line interface above, and even provides additional functionality (e.g. building and uploading projects in a single command).
Quickstart
We start by creating a configuration file for our project. Let’s call it
jobs.py
, the default file name the command line tool will look for.
Here’s a simple example of how we could define a project with a single job and
static file:
from azkaban import Job, Project
project = Project('foo')
project.add_file('/path/to/bar.txt', 'bar.txt')
project.add_job('bar', Job({'type': 'command', 'command': 'cat bar.txt'}))
The add_file
method adds a file to the project archive (the second
optional argument specifies the destination path inside the zip file). The
add_job
method will trigger the creation of a .job
file. The
first argument will be the file’s name, the second is a Job
instance
(cf. Job options).
Once we’ve saved our jobs file, the following additional commands are available to us:
azkaban list
, see the list of all jobs in the current project.azkaban view
, view the contents of the.job
file for a given job.azkaban build
, build the project archive and store it locally.
Job options
The Job
class is a light wrapper which allows the creation of
.job
files using python dictionaries.
It also provides a convenient way to handle options shared across multiple jobs: the constructor can take in multiple options dictionaries and the last definition of an option (i.e. later in the arguments) will take precedence over earlier ones.
We can use this to efficiently share default options among jobs, for example:
defaults = {'user.to.proxy': 'boo', 'retries': 0}
jobs = [
Job({'type': 'noop'}),
Job(defaults, {'type': 'noop'}),
Job(defaults, {'type': 'command', 'command': 'ls'}),
Job(defaults, {'type': 'command', 'command': 'ls -l', 'retries': 1}),
]
All jobs except the first one will have their user.to.proxy
property
set. Note also that the last job overrides the retries
property.
Alternatively, if we really don’t want to pass the defaults dictionary around,
we can create a new Job
subclass to do it for us:
class BooJob(Job):
def __init__(self, *options):
super(BooJob, self).__init__(defaults, *options)
More
Nested options
Nested dictionaries can be used to group options concisely:
# e.g. this job
Job({
'proxy.user': 'boo',
'proxy.keytab.location': '/path',
'param.input': 'foo',
'param.output': 'bar',
})
# is equivalent to this one
Job({
'proxy': {'user': 'boo', 'keytab.location': '/path'},
'param': {'input': 'foo', 'output': 'bar'},
})
Pig jobs
Because pig jobs are so common, a PigJob
class is provided which
accepts a file path (to the pig script) as first constructor argument,
optionally followed by job options. It then automatically sets the job type
and adds the corresponding script file to the project.
from azkaban import PigJob
project.add_job('baz', PigJob('/.../baz.pig', {'dependencies': 'bar'}))
Using a custom pig type is as simple as changing the PigJob.type
class
variable.
Merging projects
If you have multiple projects, you can merge them together to create a single project. The merge is done in place on the project the method is called on. The first project will retain its original name.
from azkaban import Job, Project
project1 = Project('foo')
project1.add_file('/path/to/bar.txt', 'bar.txt')
project1.add_job('bar', Job({'type': 'command', 'command': 'cat bar.txt'}))
project2 = Project('qux')
project2.add_file('/path/to/baz.txt', 'baz.txt')
project2.add_job('baz', Job({'type': 'command', 'command': 'cat baz.txt'}))
# project1 will now contain baz.txt and the baz job from project2
project2.merge_into(project1)
Next steps
Any valid python code can go inside the jobs configuration file. This includes
using loops to add jobs, subclassing the base Job
class to better suit
a project’s needs (e.g. by implementing the on_add
and
on_build
handlers), …
Extensions
Pig
Azkaban comes with a azkabanpig
utility which enables us to run pig
scripts directly. azkabanpig --help
will display the list of available
options (using UDFs, substituting parameters, running several scripts in
order, etc.).
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