Platform.sh Config Reader (Python)
This library provides a streamlined and easy to use way to interact with a Platform.sh environment. It offers utility methods to access routes and relationships more cleanly than reading the raw environment variables yourself.
This library requires Python 3.5 or later.
Install
pip install platformshconfig
Usage Example
Example:
import sys
import pysolr
from platformshconfig import Config
config = Config()
if not config.is_valid_platform():
sys.exit("Not in a Platform.sh Environment.")
credentials = config.credentials('solr')
formatted = config.formatted_credentials('solr', 'pysolr')
conn = pysolr.Solr(formatted)
API Reference
Create a config object
from platformshconfig import Config
config = Config()
config
is now a Config
object that provides access to the Platform.sh environment.
The is_valid_platform()
method returns True
if the code is running in a context that has Platform.sh environment variables defined. If it returns False
then most other functions will throw exceptions if used.
Inspect the environment
The following methods return True
or False
to help determine in what context the code is running:
config.in_build()
config.in_runtime()
config.on_dedicated()
config.on_production()
Note:
Platform.sh will no longer refer to its 99.99% uptime SLA product as "Enterprise", but rather as "Dedicated". Configuration Reader libraries have in turn been updated to include an on_dedicated
method to replace on_enterprise
. For now on_enterprise
remains available. It now calls the new method and no breaking changes have been introduced.
It is recommended that you update your projects to use on_dedicated
as soon as possible, as on_enterprise
will be removed in a future version of this library.
Read environment variables
The following magic properties return the corresponding environment variable value. See the Platform.sh documentation for a description of each.
The following are available both in Build and at Runtime:
config.applicationName
config.appDir
config.project
config.treeID
config.projectEntropy
The following are available only if in_runtime()
returned True
:
config.branch
condig.documentRoot
config.smtpHost
config.environment
config.socket
config.port
Reading service credentials
Platform.sh services are defined in a services.yaml
file, and exposed to an application by listing a relationship
to that service in the application's .platform.app.yaml
file. User, password, host, etc. information is then exposed to the running application in the PLATFORM_RELATIONSHIPS
environment variable, which is a base64-encoded JSON string. The following method allows easier access to credential information than decoding the environment variable yourself.
creds = config.credentials('database')
The return value of credentials()
is a dictionary matching the relationship JSON object, which includes the appropriate user, password, host, database name, and other pertinent information. See the Service documentation for your service for the exact structure and meaning of each property. In most cases that information can be passed directly to whatever other client library is being used to connect to the service.
Formatting service credentials
In some cases the library being used to connect to a service wants its credentials formatted in a specific way; it could be a DSN string of some sort or it needs certain values concatenated to the database name, etc. For those cases you can use "Credential Formatters". A Credential Formatter is any callable
(function, anonymous function, object method, etc.) that takes a credentials array and returns any type, since the library may want different types.
Credential Formatters can be registered on the configuration object, and a few are included out of the box. That allows 3rd party libraries to ship their own formatters that can be easily integrated into the Config
object to allow easier use.
def format_my_service(credentials):
return "some string based on 'credentials'."
config.register_formatter('my_service', format_my_service)
formatted = config.formatted_credentials('database', 'my_service')
The first parameter is the name of a relationship defined in .platform.app.yaml
. The second is a formatter that was previously registered with register_formatter()
. If either the service or formatter is missing an exception will be thrown. The type of formatted
will depend on the formatter function and can be safely passed directly to the client library.
Three formatters are included out of the box:
pymongo
returns a DSN appropriate for using pymongo
to connect to MongoDB. Note that pymongo
will still need the username and password from the credentials dictionary passed as separate parameters.pysolr
returns a DSN appropriate for using pysolr
to connect to Apache Solr.postgresql_dsn
returns a DSN appropriate for postgresql connection.
Reading Platform.sh variables
Platform.sh allows you to define arbitrary variables that may be available at build time, runtime, or both. They are stored in the PLATFORM_VARIABLES
environment variable, which is a base64-encoded JSON string.
The following two methods allow access to those values from your code without having to bother decoding the values yourself:
config.variables()
This method returns a dictionary of all variables defined. Usually this method is not necessary and config.variable()
is preferred.
config.variable("foo", "default")
This method looks for the "foo" variable. If found, it is returned. If not, the optional second parameter is returned as a default.
Reading Routes
Routes on Platform.sh define how a project will handle incoming requests; that primarily means what application container will serve the request, but it also includes cache configuration, TLS settings, etc. Routes may also have an optional ID, which is the preferred way to access them.
config.get_route("main")
The get_route()
method takes a single string for the route ID ("main" in this case) and returns the corresponding route array. If the route is not found it will throw an exception.
To access all routes, or to search for a route that has no ID, the routes()
method returns an dictionary of routes keyed by their URL. That mirrors the structure of the PLATFORM_ROUTES
environment variable.
If called in the build phase an exception is thrown.
Changelog
[2.4.0] - 2021-02-03
Added
- GitHub actions for tests (
quality-assurance.yaml
) and publishing to pypi (pypi-publish.yaml
).
Changed
- named variable
prefix
on constructor renamed to var_prefix
.
Removed
[2.3.1] - 2019-11-04
Added
CHANGELOG
added.on_dedicated
method that determines if the current environment is a Platform.sh Dedicated environment. Replaces deprecated on_enterprise
method.
Changed
- Deprecates
on_enterprise
method - which is for now made to wrap around the added on_dedicated
method. on_enterprise
will be removed in a future release, so update your projects to use on_dedicated
instead as soon as possible.
[2.3.0] - 2019-09-19
Added
get_primary_route
method for accessing routes marked "primary" in routes.yaml
.get_upstream_routes
method returns an object map that includes only those routes that point to a valid upstream.
[2.2.3] - 2019-04-30
Changed
- Removes guard on
variables()
method.
[2.2.2] - 2019-04-29
Changed
- Refactors dynamic property access to be more permissive.
[2.2.1] - 2019-04-25
Changed
- More permissive check for relationships.
[2.2.0] - 2019-04-24
Added
postgresql_dsn
credential formatter; returns a DSN appropriate for PostgreSQL connection.
[2.1.1] - 2019-03-22
Changed
- Fixes build issues in
has_relationship()
and routes()
methods.
[2.1.0] - 2019-03-22
Added
has_relationship
method to determine if a relationship is defined, and thus has credentials available.
Changed
[2.0.4] - 2019-03-06
Added