Feat harp linter (#1)

* feat(linter): bundle linter.

* feat(lint): add more tests.

* doc(readme): add samples.

cmd/harp-linter/README.md

@@ -0,0 +1,138 @@
+# Harp Linter
+
+`harp` plugin that allows you to :
+
+* Lint a `Bundle` content
+
+## Build
+
+```sh
+export PATH=<harp-repository-path>/tools/bin:$PATH
+mage
+```
+
+## Install
+
+Stable release
+
+```sh
+brew install elastic/harp-plugins/harp-linter
+```
+
+Built from source
+
+```sh
+brew install --from-source elastic/harp-plugins/harp-linter
+```
+
+## Constraint Language
+
+In order to produce package constraints, `harp-linter` uses [CEL](https://github.com/google/cel-go).
+
+For complete language specification, consult this repository - <https://github.com/google/cel-spec>
+
+### Extensions
+
+* `p` exposes the current package that match the `path` filter;
+* `p.match_path(string)` return true or false if current package match the given [glob](https://github.com/gobwas/glob) path filter;
+* `p.is_cso_compliant()` return true or false according to CSO Compliance state of the current package;
+* `p.has_secret(string)` return true or false according to secret key `string` existence;
+* `p.has_all_secrets(list)` return true or false if package has all given secret keys;
+
+### RuleSet
+
+[Definition](api/proto/harp/linter/v1/linter.proto)
+
+```yaml
+apiVersion: harp.elastic.co/linter/v1
+kind: RuleSet
+meta:
+  name: harp-server
+  description: Package and secret constraints for harp-server
+  owner: [email protected]
+spec:
+  rules:
+    # Rule identifier used to violation report
+    - name: HARP-SRV-0001
+      # Human readable definition of the rule.
+      description: All package paths must be CSO compliant
+      # Package path matcher.
+      path: "*"
+      # CEL constraints expressions (implicit AND between all contraints)
+      constraints:
+        - p.is_cso_compliant()
+        - p.match_path("app/*")
+```
+
+## Sample
+
+### Check is all packages are CSO compliant
+
+```yaml
+apiVersion: harp.elastic.co/linter/v1
+kind: RuleSet
+meta:
+  name: harp-server
+  description: Package and secret constraints for harp-server
+  owner: [email protected]
+spec:
+  rules:
+    - name: HARP-SRV-0001
+      description: All package paths must be CSO compliant
+      path: "*"
+      constraints:
+        - p.is_cso_compliant()
+```
+
+Lint an empty bundle will raise an error.
+
+```sh
+$ echo '{}' | harp from jsonmap \
+  | harp-linter bundle lint --spec test/fixtures/ruleset/valid/cso.yaml
+{"level":"fatal","@timestamp":"2021-02-23T10:24:45.852Z","@caller":"[email protected]/command.go:856","@message":"unable to execute task","@appName":"harp-bundle-lint","@version":"","@revision":"8ebf40d","@appID":"BfGZbI8QYmSaXsBMWj8j0EASE67QcoP4OnC8nLl8xSXXtsY3PFEaABdfvm6c9yb3","@fields":{"error":"unable to validate given bundle: rule 'HARP-SRV-0001' didn't match any packages"}}
+```
+
+Lint valid bundle
+
+```sh
+$ echo '{"infra/aws/security/eu-central-1/ec2/ssh/default/authorized_keys":{"admin":"..."}}' \
+  | harp from jsonmap \
+  | harp-linter bundle lint --spec test/fixtures/ruleset/valid/cso.yaml
+```
+
+> No output and exit code (0) when everything is ok
+
+### Validate a secret structure
+
+```yaml
+apiVersion: harp.elastic.co/linter/v1
+kind: RuleSet
+meta:
+  name: harp-server
+  description: Package and secret constraints for harp-server
+  owner: [email protected]
+spec:
+  rules:
+    - name: HARP-SRV-0002
+      description: Database credentials
+      path: "app/qa/security/harp/v1.0.0/server/database/credentials"
+      constraints:
+        - p.has_all_secrets(['DB_HOST','DB_NAME','DB_USER','DB_PASSWORD'])
+```
+
+Lint an empty bundle will raise an error.
+
+```sh
+$ echo '{}' | harp from jsonmap \
+  | harp-linter bundle lint --spec test/fixtures/ruleset/valid/database-secret-validator.yaml
+{"level":"fatal","@timestamp":"2021-02-23T10:31:05.792Z","@caller":"[email protected]/command.go:856","@message":"unable to execute task","@appName":"harp-bundle-lint","@version":"","@revision":"8ebf40d","@appID":"2kl6OWqgNTHkBumvlEtelxpJ4V1uDQCtE5MlOS1hXaUbOYtU1rrXbEL2zswx65y4","@fields":{"error":"unable to validate given bundle: rule 'HARP-SRV-0002' didn't match any packages"}}
+```
+
+Lint an invalid bundle
+
+```sh
+echo '{"app/qa/security/harp/v1.0.0/server/database/credentials":{}}' \
+  | harp from jsonmap \
+  | harp-linter bundle lint --spec test/fixtures/ruleset/valid/database-secret-validator.yaml
+{"level":"fatal","@timestamp":"2021-02-23T10:31:24.287Z","@caller":"[email protected]/command.go:856","@message":"unable to execute task","@appName":"harp-bundle-lint","@version":"","@revision":"8ebf40d","@appID":"7pflS7bCAAsDcAiPJWm36pypWY3nHhqOQwCc9Vp1ABCm8ZUWbmGinGL5zbP1EWvn","@fields":{"error":"unable to validate given bundle: package 'app/qa/security/harp/v1.0.0/server/database/credentials' doesn't validate rule 'HARP-SRV-0002'"}}
+```

cmd/harp-linter/Taskfile.yml

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+version: '3'
+
+vars:
+  ARTIFACT: harp-aws
+
+tasks:
+  default:
+    cmds:
+      - task: build
+
+  compile:
+    desc: Compile artefact
+    cmds:
+      - go mod vendor
+      - mage compile
+
+  test:
+    desc: Test artefact
+    cmds:
+      - mage test
+
+  release:
+    desc: Generate a release
+    cmds:
+      - go mod vendor
+      - mage release
+
+  release-pack:
+    desc: Generate final artefact to publish to GH
+    cmds:
+      - rm -rf dist && mkdir dist
+      - "tar cfJ dist/{{.ARTIFACT}}-darwin-amd64-$RELEASE.tar.xz -C bin {{.ARTIFACT}}-darwin-amd64"
+      - "tar cfJ dist/{{.ARTIFACT}}-linux-amd64-$RELEASE.tar.xz -C bin {{.ARTIFACT}}-linux-amd64"
+      - "tar cfJ dist/{{.ARTIFACT}}-windows-amd64-$RELEASE.tar.xz -C bin {{.ARTIFACT}}-windows-amd64.exe"
+      - cd dist && sha256sum {{.ARTIFACT}}-*.tar.xz > {{.ARTIFACT}}-checksum.txt
+      - cd dist && gpg --detach-sign --armor {{.ARTIFACT}}-checksum.txt
+      - cat dist/{{.ARTIFACT}}-checksum.txt
+      - mage homebrew > dist/{{.ARTIFACT}}.rb