kusto

package
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 Go to latest Published: May 8, 2022 License: MIT Imports: 30 Imported by: 21

Documentation

Overview

Package kusto provides a client for accessing Azure Data Explorer, also known as Kusto.

For details on the Azure Kusto service, see: https://azure.microsoft.com/en-us/services/data-explorer/

For general documentation on APIs and the Kusto query language, see: https://docs.microsoft.com/en-us/azure/data-explorer/

Creating an Authorizer and a Client

To begin using this package, create an Authorizer and a client targeting your Kusto endpoint: 

// auth package is: "github.com/Azure/go-autorest/autorest/azure/auth"

authorizer := kusto.Authorization{
	Config: auth.NewClientCredentialsConfig(clientID, clientSecret, tenantID),
}

client, err := kusto.New(endpoint, authorizer)
if err != nil {
	panic("add error handling")
}

For more examples on ways to create an Authorization object, see the Authorization object documentation.

Querying for Rows

Kusto provides a single method for querying, Query(). Query uses a Stmt object to provides SQL-like injection protection and accepts only string constants for arguments. 

// table package is: data/table

// Query our database table "systemNodes" for the CollectionTimes and the NodeIds.
iter, err := client.Query(ctx, "database", kusto.NewStmt("systemNodes | project CollectionTime, NodeId"))
if err != nil {
	panic("add error handling")
}
defer iter.Stop()

// .Do() will call the function for every row in the table.
err = iter.Do(
	func(row *table.Row) error {
		if row.Replace {
			fmt.Println("---") // Replace flag indicates that the query result should be cleared and replaced with this row
		}
		fmt.Println(row) // As a convenience, printing a *table.Row will output csv
		return nil
	},
)
if err != nil {
	panic("add error handling")
}

Querying Rows Into Structs

Keeping our query the same, instead of printing the Rows we will simply put them into a slice of structs 

// NodeRec represents our Kusto data that will be returned.
type NodeRec struct {
	// ID is the table's NodeId. We use the field tag here to to instruct our client to convert NodeId to ID.
	ID int64 `kusto:"NodeId"`
	// CollectionTime is Go representation of the Kusto datetime type.
	CollectionTime time.Time
}

iter, err := client.Query(ctx, "database", kusto.NewStmt("systemNodes | project CollectionTime, NodeId"))
if err != nil {
	panic("add error handling")
}
defer iter.Stop()

recs := []NodeRec{}
err = iter.Do(
	func(row *table.Row) error {
		rec := NodeRec{}
		if err := row.ToStruct(&rec); err != nil {
			return err
		}
		if row.Replace {
			recs = recs[:0]  // Replace flag indicates that the query result should be cleared and replaced with this row
		}
		recs = append(recs, rec)
		return nil
	},
)
if err != nil {
	panic("add error handling")
}

A struct object can use fields to store the Kusto values as normal Go values, pointers to Go values and as value.Kusto types. The value.Kusto types are useful when you need to distiguish between the zero value of a variable and the value not being set in Kusto.

All value.Kusto types have a .Value and .Valid field. .Value is the native Go value, .Valid is a bool which indicates if the value was set. More information can be found in the sub-package data/value.

The following is a conversion table from the Kusto column types to native Go values within a struct that are allowed: 

From Kusto Type			To Go Kusto Type
==============================================================================
bool				value.Bool, bool, *bool
------------------------------------------------------------------------------
datetime			value.DateTime, time.Time, *time.Time
------------------------------------------------------------------------------
dynamic				value.Dynamic, string, *string
------------------------------------------------------------------------------
guid				value.GUID, uuid.UUID, *uuid.UUID
------------------------------------------------------------------------------
int				value.Int, int32, *int32
------------------------------------------------------------------------------
long				value.Long, int64, *int64
------------------------------------------------------------------------------
real				value.Real, float64, *float64
------------------------------------------------------------------------------
string				value.String, string, *string
------------------------------------------------------------------------------
timestamp			value.Timestamp, time.Duration, *time.Duration
------------------------------------------------------------------------------
decimal				value.Decimal, string, *string
==============================================================================

For more information on Kusto scalar types, see: https://docs.microsoft.com/en-us/azure/kusto/query/scalar-data-types/

Stmt

Every query is done using a Stmt. A Stmt is built with Go string constants and can do variable substitution using Kusto's Query Paramaters. 

// rootStmt builds a query that will gather all nodes in the DB.
rootStmt := kusto.NewStmt("systemNodes | project CollectionTime, NodeId")

// singleNodeStmt creates a new Stmt based on rootStmt and adds a "where" clause to find a single node.
// We pass a definition that sets the word ParamNodeId to a variable that will be substituted for a
// Kusto Long type (which is a a Go int64).
singleNodeStmt := rootStmt.Add(" | where NodeId == ParamNodeId").MustDefinitions(
	kusto.NewDefinitions().Must(
		kusto.ParamTypes{
			"ParamNodeId": kusto.ParamType{Type: types.Long},
		},
	),
)

// Query using our singleNodeStmt, variable substituting for ParamNodeId
iter, err := client.Query(
	ctx,
	"database",
	singleNode.MustParameters(
		kusto.NewParameters().Must(
			kusto.QueryValues{"ParamNodeId": int64(100)},
		),
	),
)

Ingest

Support for Kusto ingestion from local files, Azure Blob Storage and streaming is supported in the sub-package ingest. See documentation in that package for more details

Mocking

To support mocking for this client in your code for hermetic testing purposes, this client supports mocking the data returned by our RowIterator object. Please see the MockRows documentation for code examples.

Package Examples

Below you will find a simple and complex example of doing Query() the represent compiled code:

Example (Complex) 
// This example sets up a Query where we want to query for nodes that have a NodeId (a Kusto Long type) that has a
// particular NodeId. The will require inserting a value where ParamNodeId is in the query. We create the query
// and attach a Definition to it that indicates which words we will be substituing for and what the expected type will be.
// the MustDefinitions() will panic if the Definition is not valid. There is a non-panicing version that returns an
// error instead.
rootStmt := NewStmt("systemNodes | project CollectionTime, NodeId | where NodeId == ParamNodeId").MustDefinitions(
	NewDefinitions().Must(
		ParamTypes{
			"ParamNodeId": ParamType{Type: types.Long},
		},
	),
)

// This takes our rootStmt and creates a new Stmt that will insert 100 where ParamNodeId is in the rootStmt.
// rootStmt will remain unchanged. The Must() will panic if the QueryValues{} passed is not valid. This can
// happen because you use a type that isn't valid, like a string or int32.
// There is a non-panicing version that returns an error instead.
stmt, err := rootStmt.WithParameters(NewParameters().Must(QueryValues{"ParamNodeId": int64(100)}))
if err != nil {
	panic("add error handling")
}

// NodeRec represents our Kusto data that will be returned.
type NodeRec struct {
	// ID is the table's NodeId. We use the field tag here to to instruct our client to convert NodeId in the Kusto
	// table to ID in our struct.
	ID int64 `kusto:"NodeId"`
	// CollectionTime is Go representation of the Kusto datetime type.
	CollectionTime time.Time
}

authorizer := Authorization{Config: auth.NewClientCredentialsConfig("clientID", "clientSecret", "tenantID")}

client, err := New("endpoint", authorizer)
if err != nil {
	panic("add error handling")
}
// Be sure to close the client when you're done. (Error handling omitted for brevity.)
defer client.Close()

ctx := context.Background()

// Query our database table "systemNodes" for our specific node. We are only doing a single query here as an example,
// normally you would take in requests of some type for different NodeIds.
iter, err := client.Query(ctx, "database", stmt)
if err != nil {
	panic("add error handling")
}
defer iter.Stop()

rec := NodeRec{} // We are assuming unique NodeId, so we will only get 1 row.
err = iter.Do(
	func(row *table.Row) error {
		return row.ToStruct(&rec)
	},
)

if err != nil {
	panic("add error handling")
}

fmt.Println(rec.ID)

Output:
Example (Simple) 
// Query and capture the values and put them in a slice of structs representing the row.

// NodeRec represents our Kusto data that will be returned.
type NodeRec struct {
	// ID is the table's NodeId. We use the field tag here to to instruct our client to convert NodeId to ID.
	ID int64 `kusto:"NodeId"`
	// CollectionTime is Go representation of the Kusto datetime type.
	CollectionTime time.Time
}

authorizer := Authorization{
	Config: auth.NewClientCredentialsConfig("clientID", "clientSecret", "tenantID"),
}

client, err := New("endpoint", authorizer)
if err != nil {
	panic("add error handling")
}

// Be sure to close the client when you're done. (Error handling omitted for brevity.)
defer client.Close()

ctx := context.Background()

// Query our database table "systemNodes" for the CollectionTimes and the NodeIds.
iter, err := client.Query(ctx, "database", NewStmt("systemNodes | project CollectionTime, NodeId"))
if err != nil {
	panic("add error handling")
}
defer iter.Stop()

recs := []NodeRec{}

err = iter.Do(
	func(row *table.Row) error {
		rec := NodeRec{}
		if err := row.ToStruct(&rec); err != nil {
			return err
		}
		if row.Replace {
			recs = recs[:0]
		}
		recs = append(recs, rec)
		return nil
	},
)

if err != nil {
	panic("add error handling")
}

for _, rec := range recs {
	fmt.Println(rec.ID)
}

Output:

Index

Examples

Constants

This section is empty.

Variables

This section is empty.

Functions

This section is empty.

Types

type Authorization 

type Authorization struct {
	// Authorizer provides an authorizer to use when talking to Kusto. If this is set, the
	// Authorizer must have its Resource (also called Resource ID) set to the endpoint passed
	// to the New() constructor. This will be something like "https://somename.westus.kusto.windows.net".
	// This package will try to set that automatically for you.
	Authorizer autorest.Authorizer
	// Config provides the authorizer's config that can create the authorizer. We recommending setting
	// this instead of Authorizer, as we will automatically set the Resource ID with the endpoint passed.
	Config auth.AuthorizerConfig
}

Authorization provides the ADAL authorizer needed to access the resource. You can set Authorizer or Config, but not both.

Example (Config) 
// Create an authorizer with your Azure ClientID, Secret and TenantID.
authorizer := Authorization{
	Config: auth.NewClientCredentialsConfig("clientID", "clientSecret", "tenantID"),
}

// Normally here you take a client.
_, err := New("endpoint", authorizer)
if err != nil {
	panic("add error handling")
}

Output:
Example (Msi) 
// Create an authorizer with an Azure MSI (managed identities).
msi := auth.NewMSIConfig()

authorizer := Authorization{
	Config: msi,
}

// Normally here you take a client.
_, err := New("endpoint", authorizer)
if err != nil {
	panic("add error handling")
}

Output:

func (*Authorization) Validate 

func (a *Authorization) Validate(endpoint string) error

Validate validates the Authorization object against the endpoint an preps it for use. For internal use only.

type Client 

type Client struct {
	// contains filtered or unexported fields
}

Client is a client to a Kusto instance.

func New 

func New(endpoint string, auth Authorization, options ...Option) (*Client, error)

New returns a new Client. endpoint is the Kusto endpoint to use, example: https://somename.westus.kusto.windows.net .

func NewMockClient added in v0.6.0 

func NewMockClient() *Client

func (*Client) Auth 

func (c *Client) Auth() Authorization

Auth returns the Authorization passed to New().

func (*Client) Close added in v0.7.0 

func (c *Client) Close() error

func (*Client) Endpoint 

func (c *Client) Endpoint() string

Endpoint returns the endpoint passed to New().

func (*Client) HttpClient added in v0.7.0 

func (c *Client) HttpClient() *http.Client

func (*Client) Mgmt 

func (c *Client) Mgmt(ctx context.Context, db string, query Stmt, options ...MgmtOption) (*RowIterator, error)

Mgmt is used to do management queries to Kusto. Details can be found at: https://docs.microsoft.com/en-us/azure/kusto/management/ Mgmt accepts a Stmt, but that Stmt cannot have any query parameters attached at this time. Note that the server has a timeout of 10 minutes for a management call by default unless the context deadline is set. There is a maximum of 1 hour.

func (*Client) Query 

func (c *Client) Query(ctx context.Context, db string, query Stmt, options ...QueryOption) (*RowIterator, error)

Query queries Kusto for data. context can set a timeout or cancel the query. query is a injection safe Stmt object. Queries cannot take longer than 5 minutes by default and have row/size limitations. Note that the server has a timeout of 4 minutes for a query by default unless the context deadline is set. Queries can take a maximum of 1 hour.

Example (Do) 
// This is similar to our (Row) example. In this one though, we use the RowIterator.Do() method instead of
// manually iterating over the row. This makes for shorter code while maintaining readability.

authorizer := Authorization{
	Config: auth.NewClientCredentialsConfig("clientID", "clientSecret", "tenantID"),
}

client, err := New("endpoint", authorizer)
if err != nil {
	panic("add error handling")
}
// Be sure to close the client when you're done. (Error handling omitted for brevity.)
defer client.Close()

ctx := context.Background()

// Query our database table "systemNodes" for the CollectionTimes and the NodeIds.
iter, err := client.Query(ctx, "database", NewStmt("systemNodes | project CollectionTime, NodeId"))
if err != nil {
	panic("add error handling")
}
defer iter.Stop()

// Iterate through the returned rows until we get an error or receive an io.EOF, indicating the end of
// the data being returned.

err = iter.Do(
	func(row *table.Row) error {
		if row.Replace {
			fmt.Println("---") // Replace flag indicates that the query result should be cleared and replaced with this row
		}
		for _, v := range row.Values {
			fmt.Printf("%s,", v)
		}
		fmt.Println("") // Add a carriage return
		return nil
	},
)
if err != nil {
	panic("add error handling")
}

Output:
Example (Rows) 
authorizer := Authorization{
	Config: auth.NewClientCredentialsConfig("clientID", "clientSecret", "tenantID"),
}

client, err := New("endpoint", authorizer)
if err != nil {
	panic("add error handling")
}
// Be sure to close the client when you're done. (Error handling omitted for brevity.)
defer client.Close()

ctx := context.Background()

// Query our database table "systemNodes" for the CollectionTimes and the NodeIds.
iter, err := client.Query(ctx, "database", NewStmt("systemNodes | project CollectionTime, NodeId"))
if err != nil {
	panic("add error handling")
}
defer iter.Stop()

// Iterate through the returned rows until we get an error or receive an io.EOF, indicating the end of
// the data being returned.
for {
	row, err := iter.Next()
	if err != nil {
		if err == io.EOF {
			break
		}
		if err != nil {
			panic("add error handling")
		}
	}

	// Print out the row values
	for _, v := range row.Values {
		fmt.Printf("%s,", v)
	}
	fmt.Println("") // Add a carriage return
}

Output:
Example (Struct) 
// Capture our values into a struct and sends those values into a channel. Normally this would be done between
// a couple of functions representing a sender and a receiver.

// NodeRec represents our Kusto data that will be returned.
type NodeRec struct {
	// ID is the table's NodeId. We use the field tag here to to instruct our client to convert NodeId to ID.
	ID int64 `kusto:"NodeId"`
	// CollectionTime is Go representation of the Kusto datetime type.
	CollectionTime time.Time

	// err is used internally to signal downstream that we encounter an error.
	err error
}

authorizer := Authorization{
	Config: auth.NewClientCredentialsConfig("clientID", "clientSecret", "tenantID"),
}

client, err := New("endpoint", authorizer)
if err != nil {
	panic("add error handling")
}
// Be sure to close the client when you're done. (Error handling omitted for brevity.)
defer client.Close()

ctx := context.Background()

// Query our database table "systemNodes" for the CollectionTimes and the NodeIds.
iter, err := client.Query(ctx, "database", NewStmt("systemNodes | project CollectionTime, NodeId"))
if err != nil {
	panic("add error handling")
}
defer iter.Stop()

// printCh is used to receive NodeRecs for printing.
printCh := make(chan NodeRec, 1)

// Iterate through the returned rows, convert them to NodeRecs and send them on printCh to be printed.
go func() {
	// Note: we ignore the error here because we send it on a channel and an error will automatically
	// end the iteration.
	iter.Do(
		func(row *table.Row) error {
			rec := NodeRec{}
			rec.err = row.ToStruct(&rec)
			printCh <- rec
			return rec.err
		},
	)
}()

// Receive the NodeRecs on printCh and print them to the screen.
wg := sync.WaitGroup{}
wg.Add(1)
go func() {
	defer wg.Done()
	for rec := range printCh {
		if rec.err != nil {
			fmt.Println("Got error: ", err)
			return
		}
		fmt.Printf("NodeID: %d, CollectionTime: %s\n", rec.ID, rec.CollectionTime)
	}
}()

wg.Wait()

Output:

type Definitions 

type Definitions struct {
	// contains filtered or unexported fields
}

Definitions represents definitions of parameters that are substituted for variables in a Kusto Query. This provides both variable substitution in a Stmt and provides protection against SQL-like injection attacks. See https://docs.microsoft.com/en-us/azure/kusto/query/queryparametersstatement?pivots=azuredataexplorer for internals. This object is not thread-safe and passing it as an argument to a function will create a copy that will share the internal state with the original.

func NewDefinitions 

func NewDefinitions() Definitions

NewDefinitions is the constructor for Definitions.

func (Definitions) IsZero 

func (p Definitions) IsZero() bool

IsZero indicates if the Definitions object is the zero type.

func (Definitions) Must 

func (p Definitions) Must(types ParamTypes) Definitions

Must is the same as With(), but it must succeed or it panics.

func (Definitions) String 

func (p Definitions) String() string

String implements fmt.Stringer.

func (Definitions) With 

func (p Definitions) With(types ParamTypes) (Definitions, error)

With returns a copy of the Definitions object with the parameters names and types defined in "types".

type MgmtOption 

type MgmtOption func(m *mgmtOptions) error

MgmtOption is an option type for a call to Mgmt().

func AllowWrite 

func AllowWrite() MgmtOption

AllowWrite allows a query that attempts to modify data in a table.

func IngestionEndpoint 

func IngestionEndpoint() MgmtOption

IngestionEndpoint will instruct the Mgmt call to connect to the ingest-[endpoint] instead of [endpoint]. This is not often used by end users and can only be used with a Mgmt() call.

type MockRows 

type MockRows struct {
	// contains filtered or unexported fields
}

MockRows provides the abilty to provide mocked Row data that can be played back from a RowIterator. This allows for creating hermetic tests from mock data or creating mock data from a real data fetch.

func NewMockRows 

func NewMockRows(columns table.Columns) (*MockRows, error)

NewMockRows is the constructor for MockRows.

func (*MockRows) Error 

func (m *MockRows) Error(err error) error

Error adds an error into the result stream. Nothing else added to this stream will matter once this is called.

func (*MockRows) Row 

func (m *MockRows) Row(row value.Values) error

Row adds Row data that will be replayed in a RowIterator.

func (*MockRows) Struct 

func (m *MockRows) Struct(p interface{}) error

Struct adds Row data that will be replayed in a RowIterator by parsing the passed *struct into value.Values.

type Option 

type Option func(c *Client)

Option is an optional argument type for New().

func WithHttpClient added in v0.7.0 

func WithHttpClient(client *http.Client) Option

type ParamType 

type ParamType struct {
	// Type is the type of Column type this QueryParam will represent.
	Type types.Column
	// Default is a default value to use if the query doesn't provide this value.
	// The value that can be set is defined by the Type:
	// CTBool must be a bool
	// CTDateTime must be a time.Time
	// CTDynamic cannot have a default value
	// CTGuid must be an uuid.UUID
	// CTInt must be an int32
	// CTLong must be an int64
	// CTReal must be an float64
	// CTString must be a string
	// CTTimespan must be a time.Duration
	// CTDecimal must be a string or *big.Float representing a decimal value
	Default interface{}
	// contains filtered or unexported fields
}

ParamType provides type and default value information about the query parameter

type ParamTypes 

type ParamTypes map[string]ParamType

ParamTypes is a list of parameter types and corresponding type data.

type Parameters 

type Parameters struct {
	// contains filtered or unexported fields
}

Parameters represents values that will be substituted for a Stmt's Parameter. Keys are the names of corresponding Parameters, values are the value to be used. Keys must exist in the Parameter and value must be a Go type that corresponds to the ParamType.

func NewParameters 

func NewParameters() Parameters

NewParameters is the construtor for Parameters.

func (Parameters) IsZero 

func (q Parameters) IsZero() bool

IsZero returns if Parameters is the zero value.

func (Parameters) Must 

func (q Parameters) Must(values QueryValues) Parameters

Must is the same as With() except any error is a panic.

func (Parameters) With 

func (q Parameters) With(values QueryValues) (Parameters, error)

With returns a Parameters set to "values". values' keys represents Definitions names that will substituted for and the values to be subsituted.

type QueryOption 

type QueryOption func(q *queryOptions) error

QueryOption is an option type for a call to Query().

func ResultsProgressiveDisable 

func ResultsProgressiveDisable() QueryOption

ResultsProgressiveDisable disables the progressive query stream.

type QueryValues 

type QueryValues map[string]interface{}

QueryValues represents a set of values that are substituted in Parameters. Every QueryValue key must have a corresponding Parameter name. All values must be compatible with the Kusto Column type it will go into (int64 for a long, int32 for int, time.Time for datetime, ...)

type Row added in v0.6.0 

type Row struct {
	Values  value.Values
	Error   *errors.Error
	Replace bool
}

Row is a row of data from Kusto, or an error. Replace indicates whether the existing result set should be cleared and replaced with this row.

type RowIterator 

type RowIterator struct {

	// RequestHeader is the http.Header sent in the request to the server.
	RequestHeader http.Header
	// ResponseHeader is the http.header sent in the response from the server.
	ResponseHeader http.Header
	// contains filtered or unexported fields
}

RowIterator is used to iterate over the returned Row objects returned by Kusto.

func (*RowIterator) Do deprecated 

func (r *RowIterator) Do(f func(r *table.Row) error) error

Deprecated: Use DoOnRowOrError() instead for more robust error handling. In a future version, this will be removed, and NextRowOrError will replace it. Do calls f for every row returned by the query. If f returns a non-nil error, iteration stops. This method will fail on errors inline within the rows, even though they could potentially be recovered and more data might be available. This behavior is to keep the interface compatible.

func (*RowIterator) DoOnRowOrError added in v0.6.0 

func (r *RowIterator) DoOnRowOrError(f func(r *table.Row, e *errors.Error) error) error

DoOnRowOrError calls f for every row returned by the query. If errors occur inline within the rows, they are passed to f. Other errors will stop the iteration and be returned. If f returns a non-nil error, iteration stops.

func (*RowIterator) GetExtendedProperties added in v0.6.0 

func (r *RowIterator) GetExtendedProperties() (v2.DataTable, error)

GetExtendedProperties will return the extended properties' table from the iterator, if it exists. Returns io.ErrUnexpectedEOF if not found. May not have all tables until RowIterator has reached io.EOF.

func (*RowIterator) GetNonPrimary added in v0.6.0 

func (r *RowIterator) GetNonPrimary(tableKind, tableName frames.TableKind) (v2.DataTable, error)

GetNonPrimary will return a non-primary dataTable if it exists from the last query. The non-primary table and common names are defined under the frames.TableKind enum. Returns io.ErrUnexpectedEOF if not found. May not have all tables until RowIterator has reached io.EOF.

func (*RowIterator) GetQueryCompletionInformation added in v0.6.0 

func (r *RowIterator) GetQueryCompletionInformation() (v2.DataTable, error)

GetQueryCompletionInformation will return the query completion information table from the iterator, if it exists. Returns io.ErrUnexpectedEOF if not found. May not have all tables until RowIterator has reached io.EOF.

func (*RowIterator) Mock 

func (r *RowIterator) Mock(m *MockRows) error

Mock is used to tell the RowIterator to return specific data for tests. This is useful when building fakes of the client's Query() call for hermetic tests. This can only be called in a test or it will panic.

func (*RowIterator) Next deprecated 

func (r *RowIterator) Next() (row *table.Row, finalError error)

Deprecated: Use NextRowOrError() instead for more robust error handling. In a future version, this will be removed, and NextRowOrError will replace it. Next gets the next Row from the query. io.EOF is returned if there are no more entries in the output. This method will fail on errors inline within the rows, even though they could potentially be recovered and more data might be available. Once Next() returns an error, all subsequent calls will return the same error.

func (*RowIterator) NextRowOrError added in v0.6.0 

func (r *RowIterator) NextRowOrError() (row *table.Row, inlineError *errors.Error, finalError error)

NextRowOrError gets the next Row or service-side error from the query. On partial success, inlineError will be set. Once finalError returns non-nil, all subsequent calls will return the same error. finalError will be set to io.EOF is when frame parsing completed with success or partial success (data + errors). if finalError is not io.EOF, reading the frame has resulted in a failure state (no data is expected).

func (*RowIterator) Progress 

func (r *RowIterator) Progress() float64

Progress returns the progress of the query, 0-100%. This is only valid on Progressive data returns.

func (*RowIterator) Progressive 

func (r *RowIterator) Progressive() bool

Progressive indicates if the RowIterator is unpacking progressive (streaming) frames.

func (*RowIterator) Stop 

func (r *RowIterator) Stop()

Stop is called to stop any further iteration. Always defer a Stop() call after receiving a RowIterator.

type Stmt 

type Stmt struct {
	// contains filtered or unexported fields
}

Stmt is a Kusto Query statement. A Stmt is thread-safe, but methods on the Stmt are not. All methods on a Stmt do not alter the statement, they return a new Stmt object with the changes. This includes a copy of the Definitions and Parameters objects, if provided. This allows a root Stmt object that can be built upon. You should not pass *Stmt objects.

Example 
package main

import (
	"fmt"

	"github.com/Azure/azure-kusto-go/kusto"
	"github.com/Azure/azure-kusto-go/kusto/data/types"
)

const (
	// qRoot is a a root query text that will be used in a Stmt. It contains everything that any
	// other Stmt objects will need.
	qRoot = "set notruncation;dcmInventoryComponentSystem\n| project NodeId, Version"
	// singleNode includes syntax that will be included only when we want to grab a single node.
	// The word "Node" here is substituted for variable.
	singleNode = "\n| where NodeId == Node\n"
)

var (
	// rootStmt represents our root Stmt object in which we can derive other Stmts. This definition
	// will always include NodeId and Version fields.
	rootStmt = kusto.NewStmt(qRoot)
	// singleStmt is derived from the rootStmt but includes a where clause to limit the query to a
	// single node. You will see that we input a Definitions object to define the "Node" word in the
	// query as a string.
	singleStmt = rootStmt.Add(singleNode).MustDefinitions(
		kusto.NewDefinitions().Must(
			kusto.ParamTypes{
				"Node": kusto.ParamType{Type: types.String},
			},
		),
	)
)

func main() {
	var err error

	// This will print the rootStmt that could be used to list all nodes in the table.
	fmt.Println("All Nodes Statement:\n", rootStmt.String())

	// If we wanted to query for a single node, we could build a Stmt fron singleStmt like so:
	params := kusto.NewParameters()
	params, err = params.With(kusto.QueryValues{"Node": "my_id"}) // Substitute "my_id" in every place in the query where "Node" is
	if err != nil {
		panic(err)
	}

	stmt, err := singleStmt.WithParameters(params)
	if err != nil {
		panic(err)
	}

	fmt.Println("Single Statement:\n", stmt)
	j, err := stmt.ValuesJSON()
	if err != nil {
		panic(err)
	}
	fmt.Println("Single Statement Parameters:\n", j)

	// Here is a more condensed version:
	stmt, err = singleStmt.WithParameters(kusto.NewParameters().Must(kusto.QueryValues{"Node": "my_id2"}))
	if err != nil {
		panic(err)
	}

	fmt.Println("Single Statement(Condensed):\n", stmt)

	// For repeated queries off a channel or loop, we can further optimize.
	params = kusto.NewParameters()
	qv := kusto.QueryValues{}

	qv["Node"] = "node id from channel"
	stmt, err = singleStmt.WithParameters(params.Must(qv))
	if err != nil {
		panic(err)
	}

	fmt.Println("Single Statement(Repeat):\n", stmt)

}

Output:

All Nodes Statement:
 set notruncation;dcmInventoryComponentSystem
| project NodeId, Version
Single Statement:
 declare query_parameters(Node:string);
set notruncation;dcmInventoryComponentSystem
| project NodeId, Version
| where NodeId == Node

Single Statement Parameters:
 {"Node":"my_id"}
Single Statement(Condensed):
 declare query_parameters(Node:string);
set notruncation;dcmInventoryComponentSystem
| project NodeId, Version
| where NodeId == Node

Single Statement(Repeat):
 declare query_parameters(Node:string);
set notruncation;dcmInventoryComponentSystem
| project NodeId, Version
| where NodeId == Node

func NewStmt 

func NewStmt(query stringConstant, options ...StmtOption) Stmt

NewStmt creates a Stmt from a string constant.

func (Stmt) Add 

func (s Stmt) Add(query stringConstant) Stmt

Add will add more text to the Stmt. This is similar to the + operator on two strings, except it only can be done with string constants. This allows dynamically building of a query from a root Stmt.

func (Stmt) MustDefinitions 

func (s Stmt) MustDefinitions(defs Definitions) Stmt

MustDefinitions is the same as WithDefinitions with the exceptions that an error causes a panic.

func (Stmt) MustParameters 

func (s Stmt) MustParameters(params Parameters) Stmt

MustParameters is the same as WithParameters with the exceptions that an error causes a panic.

func (Stmt) String 

func (s Stmt) String() string

String implements fmt.Stringer. This can be used to see what the query statement to the server will be for debugging purposes.

func (Stmt) UnsafeAdd 

func (s Stmt) UnsafeAdd(query string) Stmt

UnsafeAdd provides a method to add strings that are not injection protected to the Stmt. To utilize this method, you must create the Stmt with the UnsafeStmt() option and pass the unsafe.Stmt with .Add set to true. If not set, THIS WILL PANIC!

func (Stmt) ValuesJSON 

func (s Stmt) ValuesJSON() (string, error)

ValuesJSON returns a string in JSON format representing the Kusto QueryOptions.Parameters value that will be passed to the server. These values are substitued for Definitions in the Stmt and are represented by the Parameters that was passed.

func (Stmt) WithDefinitions 

func (s Stmt) WithDefinitions(defs Definitions) (Stmt, error)

WithDefinitions will return a Stmt that can be used in a Query() with Kusto Parameters to protect against SQL-like injection attacks. These Parameters must align with the placeholders in the statement. The new Stmt object will have a copy of the Parameters passed, not the original.

func (Stmt) WithParameters 

func (s Stmt) WithParameters(params Parameters) (Stmt, error)

WithParameters returns a Stmt that has the Parameters that will be substituted for Definitions in the query. Must have supplied the appropriate Definitions using WithQueryParamaters().

type StmtOption 

type StmtOption func(s *Stmt)

StmtOption is an optional argument to NewStmt().

func UnsafeStmt 

func UnsafeStmt(options unsafe.Stmt) StmtOption

UnsafeStmt enables unsafe actions on a Stmt and all Stmts derived from that Stmt. This turns off safety features that could allow a service client to compromise your data store. USE AT YOUR OWN RISK!

type TableOfContents added in v0.4.2 

type TableOfContents struct {
	Ordinal    int64
	Kind       string
	Name       string
	Id         string
	PrettyName string
}

Source Files

View all Source files

Directories

Path Synopsis
data
errors
Package errors provides the error package for Kusto.
 Package errors provides the error package for Kusto.
table
Package table contains types that represent the makeup of a Kusto table.
 Package table contains types that represent the makeup of a Kusto table.
types
Package types holds Kusto type information that is used to describe what type would be held in a cell based on the column's type setting.
 Package types holds Kusto type information that is used to describe what type would be held in a cell based on the column's type setting.
value
Package value holds Kusto data value representations.
 Package value holds Kusto data value representations.
Package ingest provides data ingestion from various external sources into Kusto.
 Package ingest provides data ingestion from various external sources into Kusto.
internal/conn
Package conn holds a streaming ingest connetion.
 Package conn holds a streaming ingest connetion.
internal/gzip
Package gzip provides a streaming object for taking in io.ReadCloser that is being written to and providing an io.ReadCloser that outputs the original content gzip compressed.
 Package gzip provides a streaming object for taking in io.ReadCloser that is being written to and providing an io.ReadCloser that outputs the original content gzip compressed.
internal/properties
Package properties provides Kusto REST properties that will need to be serialized and sent to Kusto based upon the type of ingestion we are doing.
 Package properties provides Kusto REST properties that will need to be serialized and sent to Kusto based upon the type of ingestion we are doing.
internal/queued
Package filesystem provides a client with the ability to import data into Kusto via a variety of fileystems such as local storage or blobstore.
 Package filesystem provides a client with the ability to import data into Kusto via a variety of fileystems such as local storage or blobstore.
internal/resources
Package resources contains objects that are used to gather information about Kusto resources that are used during various ingestion methods.
 Package resources contains objects that are used to gather information about Kusto resources that are used during various ingestion methods.
internal/status
internal
frames
frames/unmarshal
Package unmarshal provides decoding of Kusto row data in a frame into []value.Values representing those rows.
 Package unmarshal provides decoding of Kusto row data in a frame into []value.Values representing those rows.
frames/unmarshal/json
Package json implements encoding and decoding of JSON as defined in RFC 7159.
 Package json implements encoding and decoding of JSON as defined in RFC 7159.
frames/v1
Package v1 holds framing information for the v1 REST API.
 Package v1 holds framing information for the v1 REST API.
frames/v2
Package v2 holds framing information for the v2 REST API.
 Package v2 holds framing information for the v2 REST API.
log
response
version
Package version keeps the internal version number of the client.
 Package version keeps the internal version number of the client.
test
etoe
Package unsafe provides methods and types that loosen the native protections of the Kusto package.
 Package unsafe provides methods and types that loosen the native protections of the Kusto package.

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