ksql, a SQL-like language tool for kubernetes

Install

CGO_ENABLED=0 go install github.com/imuxin/ksql

Goal #1: bring SQL lanugage for kubernetes command line tool

Rule #1: JSONPath Support in column name and where filter

More jsonpath support details, please check kubernetes kubectl jsonpath support.

Rule #2: NAMESPACE LABEL NAME keyword support in sql statement

• ps1: NS is abbreviation for NAMESPACE
• ps2: NAME and LABEL are allowed to have multiple inputs
• ps3: NS or NAMESPACE is required once NAME is used.

Examples:

• SELECT

ksql> SELECT * FROM service NAMESPACE default NAME kubernetes
+------------+-----------+
| NAME       | NAMESPACE |
+------------+-----------+
| kubernetes | default   |
+------------+-----------+
ksql> SELECT "{ .metadata.name }" AS NAME, "{ .spec.clusterIP }" AS "CLUSTER-IP", "{ .spec.ports }" FROM svc NAMESPACE default NAME kubernetes
+------------+------------+------------------------------------------------------------------+
| NAME       | CLUSTER-IP | { .SPEC.PORTS }                                                  |
+------------+------------+------------------------------------------------------------------+
| kubernetes | 10.8.0.1   | [{"name":"https","port":443,"protocol":"TCP","targetPort":6443}] |
+------------+------------+------------------------------------------------------------------+

• DESC

ksql> DESC envoyfilters.networking.istio.io
+-------------------------------------------------------------------------------------------------+----------+
| SCHEMA                                                                                          | VERSION  |
+-------------------------------------------------------------------------------------------------+----------+
| type EnvoyFilter struct {                                                                       | v1alpha3 |
|     // Customizing Envoy configuration generated by Istio. See more details at:                 |          |
|     // https://istio.io/docs/reference/config/networking/envoy-filter.html                      |          |
|     spec struct {                                                                               |          |
|         // One or more patches with match conditions.                                           |          |
|         configPatches []struct {                                                                |          |
|             applyTo string                                                                      |          |
|             // Match on listener/route configuration/cluster.                                   |          |
|             match struct {                                                                      |          |
|                 // Match on envoy cluster attributes.                                           |          |
|                 cluster struct {                                                                |          |
|                     // The exact name of the cluster to match.                                  |          |
|                     name string                                                                 |          |
|                     // The service port for which this cluster was generated.                   |          |
|                     portNumber int                                                              |          |
|                     // The fully qualified service name for this cluster.                       |          |
|                     service string                                                              |          |
|                     // The subset associated with the service.                                  |          |
|                     subset string                                                               |          |
|                 }                                                                               |          |
|                                                                                                 |          |
|                 ...                                                                             |          |
|                                                                                                 |          |
|     status map[string]interface{}                                                               |          |
| }                                                                                               |          |
+-------------------------------------------------------------------------------------------------+----------+

more usages, see EBNF description:

ksql/pkg/parser/parser_test.go

Lines 11 to 23 in 86e6270

	const EBNF = `KSQL = UseStat* SelectStat* .
	UseStat = "USE" <ident> .
	SelectStat = "SELECT" SelectExpr "FROM" FromExpr ("WHERE" WhereExpr)? (("NAMESPACE" | "NS") (<ident> | <string>))? KubernetesFilter* .
	SelectExpr = "*" | (Column ("," Column)*) .
	Column = (<ident> | <string>) ("AS" (<ident> | <string> | "NAMESPACE" | "NS" | "NAME" | "SELECT" | "LABEL"))? .
	FromExpr = (<ident> | "NAMESPACE" | "NS" | "NAME" | "SELECT" | "LABEL") ("@" <ident>)? .
	WhereExpr = Compare Condition* .
	Compare = "NOT"? (<ident> | <string>) Operation .
	Operation = (("NOT"? "EXISTS") | (("<>" | "<=" | ">=" | "=" | "==" | "<" | ">" | "!=" | ("NOT"? "IN")) Value)) .
	Value = (<number> | <string> | <ident> | ("TRUE" | "FALSE") | "NULL" | Array) .
	Array = "(" Value ("," Value)* ")" .
	Condition = ("AND" | "OR" | "NOT") Compare .
	KubernetesFilter = ("LABEL" Compare) | ("NAME" (<ident> | <string>)) .`

Goal #2: make code easier to maintain

client-go

ksql

func list() ([]T, error) { kubeConfig := getKubeConfig() client, err := dynamic. NewForConfig(kubeConfig) if err != nil { return nil, err } gvr := schema.GroupVersionResource{ Group: "k8s.io", Version: "v1alpha1", Resource: "tttt", } s := labels.NewSelector() req, err := labels.NewRequirement( "key", selection.Equals, []string{"val"}) if err != nil { return nil, err } s = s.Add(*req) us, err := client. Resource(gvr). List(context.TODO(), metav1.ListOptions{ LabelSelector: s.String(), }) if err != nil { return nil, err } var results []T for _, item := range us.Items { obj := &T{} if err := FromUnstructured( item.Object, obj); err != nil { return nil, err } results = append(results, *obj) } return results, nil }

import "github.com/imuxin/ksql/pkg/executor" func list() ([]T, error) { kubeConfig := getKubeConfig() sql := `SELECT * FROM tttt.v1alpha1.k8s.io LABEL key = val` return executor.Execute[T](sql, kubeConfig) }

Roadmap

• Support SELECT stat
• Support FROM
• Support AS LABEL NAMESPACE NAME
• Support WHERE expr
• Support DESC expr
• Support USE stat
• Support DELETE stat
• Support UPDATE stat
• Support custom TABLE extensions
• ...