salty-dog/README.md

SALTY DOG

Rule-based YAML validator using JSON schemas. Capable of filtering elements to validate partial documents, supports multiple documents per stream or file, inserting defaults, and other magic.

• SALTY DOG
  • Usage
    • Docker
    • Check Mode
    • Fix Mode
      • Default Values
      • Coercing Values
  • Rules
    • Enabling Rules
    • Validate Rules
  • Build

Usage

salty-dog is distributed as a package or container.

While the container is the preferred way of running salty-dog, it has a serious limitation: docker run combines stdout and stderr, making it impossible to separate logs and the output document. Writing either the logs or dest to a file works around this.

To download, validate, and apply a Kubernetes resource:

> curl https://raw.githubusercontent.com/ssube/k8s-shards/master/roles/apps/gitlab/server/templates/ingress.yml |\
    salty-dog \
    --rules rules/kubernetes.yml \
    --source - \
    --tag important | kubectl apply --dry-run -f -

...
{"name":"salty-dog","hostname":"cerberus","pid":7860,"level":30,"msg":"all rules passed","time":"2019-06-16T02:04:37.797Z","v":0}
ingress.extensions/gitlab created (dry run)

Docker

To run with Docker: docker run --rm ssube/salty-dog:master

The latest semi-stable image is ssube/salty-dog:master. All tags are listed here.

The Docker container is published for each branch and git tag, tagged with the version slug (. replaced with -, mostly).

Rules are baked into the image in /salty-dog/rules. To use custom rules, mount them with -v $(pwd)/rules:/salty-dog/rules:ro and load with --rules /rules/foo.yml.

Check Mode

By default, salty-dog will validate the structure and contents of the --source document. If all rules pass, the document will be printed to --dest.

> cat examples/kubernetes-resources-pass.yml | salty-dog \
    --rules rules/kubernetes.yml \
    --tag important

...
[2019-06-15T23:53:34.223Z]  INFO: salty-dog/19839 on cerberus: all rules passed

> cat examples/kubernetes-resources-fail.yml | salty-dog \
    --rules rules/kubernetes.yml \
    --tag important

...
[2019-06-15T23:56:04.764Z] ERROR: salty-dog/22211 on cerberus: some rules failed (errors=1)

The --source and --dest default to stdin and stdout, respectively, but a path may be provided:

> salty-dog \
    --rules rules/kubernetes.yml \
    --tag important \
    --source examples/kubernetes-resources-pass.yml \
    --dest /tmp/kubernetes-resource.yml

...
[2019-06-15T23:53:34.223Z]  INFO: salty-dog/19839 on cerberus: all rules passed

Fix Mode

salty-dog can also add default values to missing properties with --mode fix. If a rule does not immediately pass with the --source document, but defaults are provided in the schema, the defaults will be inserted before printing to --dest.

Default Values

Properties that appear in the schema with a default provided will be added to each element as it is checked. Rules apply in order, as do their defaults.

Coercing Values

Properties that appear in the document with a different type than they have in the schema may be coerced, if the value is compatible with the schema type. The full matrix of valid type coercions is documented by Ajv.

Rules

Rules combine a jsonpath expression and JSON schema to select and validate the document.

The rule's select expression is used to select nodes that should be validated, which are filtered, then checked.

The structure of rule files and the rules within them are documented here.

Enabling Rules

All rules are disabled by default and must be enabled by name, level, or tag.

To enable a single rule by name, --include-name foo-rule.

To enable a group of rules by level, --include-level warn.

To enable a group of rules by tag, --include-tag foo.

Validate Rules

To validate the rules in the rules/ directory using the meta-rules:

> make run-rules

...
{"name":"salty-dog","hostname":"cerberus","pid":29403,"level":30,"msg":"all rules passed","time":"2019-06-16T00:56:55.132Z","v":0}

Build

This project is written in Typescript and requires node and yarn to build.

> git clone git@github.com:ssube/salty-dog.git
> cd salty-dog
> make

After building, run with: node out/main.js

make targets are provided for some common arguments:

> curl https://raw.githubusercontent.com/ssube/k8s-shards/master/roles/apps/gitlab/server/templates/ingress.yml | make run-stream 2> >(./node_modules/.bin/bunyan) > >(kubectl apply --dry-run -f -)

...
[2019-06-16T03:23:56.645Z]  INFO: salty-dog/8015 on cerberus: all rules passed
ingress.extensions/gitlab created (dry run)