Static Context

Mastermind Sprig

Many of the utility functions provided come from Sprig, a third-party library of Go template functions. The Sprig documentation can be found here.

Namespace

func Namespace() string

Namespace returns the Kubernetes namespace that the KOTS application belongs to.

'{{repl Namespace}}'

KubeSeal

func KubeSeal(certData string, namespace string, name string, value string) string

HumanSize

func HumanSize(size interface{}) string

HumanSize returns a human-readable approximation of a size in bytes capped at 4 valid numbers (eg. “2.746 MB”, “796 KB”). The size must be a integer or floating point number.

'{{repl ConfigOption "min_size_bytes" | HumanSize }}'

Now

func Now() string

Returns the current timestamp as an RFC3339 formatted string.

'{{repl Now }}'

NowFmt

func NowFmt(format string) string

Returns the current timestamp as a formatted string. See Go’s time formatting guidelines here.

'{{repl Now "20060102" }}'

ToLower

func ToLower(stringToAlter string) string

Returns the string, in lowercase.

'{{repl ConfigOption "company_name" | ToLower }}'

ToUpper

func ToUpper(stringToAlter string) string

Returns the string, in uppercase.

'{{repl ConfigOption "company_name" | ToUpper }}'

TrimSpace

func TrimSpace(s string) string

Trim returns a string with all leading and trailing spaces removed.

'{{repl ConfigOption "str_value" | TrimSpace }}'

Trim

func Trim(s string, args ...string) string

Trim returns a string with all leading and trailing string contained in the optional args removed (default space).

'{{repl ConfigOption "str_value" | Trim " " "." }}'

UrlEncode

func UrlEncode(stringToEncode string) string

Returns the string, url encoded. Equivalent to the QueryEscape function within the golang net/url library.

'{{repl ConfigOption "smtp_email" | UrlEncode }}:{{repl ConfigOption "smtp_password" | UrlEncode }}@smtp.example.com:587'

UrlPathEscape

func UrlPathEscape(stringToEncode string) string

Returns the string, url path encoded. Equivalent to the PathEscape function within the golang net/url library.

'{{repl ConfigOption "smtp_email" | UrlPathEscape }}:{{repl ConfigOption "smtp_password" | UrlPathEscape }}@smtp.example.com:587'

Base64Encode

func Base64Encode(stringToEncode string) string

Returns a Base64 encoded string.

'{{repl ConfigOption "name" | Base64Encode }}'

Base64Decode

func Base64Decode(stringToDecode string) string

Returns decoded string from a Base64 stored value.

'{{repl ConfigOption "base_64_encoded_name" | Base64Decode }}'

Split

func Split(s string, sep string) []string

Split slices s into all substrings separated by sep and returns an array of the substrings between those separators.

'{{repl Split "A,B,C" "," }}'

Combining Split and index: Assuming the github_url param is set to https://github.mycorp.internal:3131, the following would set GITHUB_HOSTNAME to github.mycorp.internal.

'{{repl index (Split (index (Split (ConfigOption "github_url") "/") 2) ":") 0}}'

RandomString

func RandomString(length uint64, providedCharset ...string) string

Returns a random string with the desired length and charset. Provided charsets must be Perl formatted and match individual characters. If no charset is provided, [_A-Za-z0-9] will be used.

'{{repl RandomString 64}}'

Or for a total of 64 as and bs:

'{{repl RandomString 64 "[ab]" }}'

Each time that this function is called, the behavior changes based on the hidden and readonly properties.

• To generate a RandomString value that is persistent between Config changes, use it in conjunction with hidden property set to true. The value is not shown in HTML, hence it cannot be modified.
• To generate a RandomString value that is ephemeral between Config changes, use it in conjunction with readonly property set to true. The value is shown in HTML but the it cannot be modified.
• If hidden and readonly are not set or set to false, the value is persistent between Config changes but it can also be modified in HTML.
• If both hidden and readonly are set to true, the value is not shown in HTML but it is ephemeral between Config changes and not modifiable.

Add

func Add(x interface{}, y interface{}) interface{}

Adds x and y.

If at least one of the operands is a floating point number, the result will be a floating point number.

If both operands are integers, the result will be an integer.

'{{repl Add (ConfigOption "maximum_users") 1}}'

Sub

func Sub(x interface{}, y interface{}) interface{}

Subtracts y from x.

If at least one of the operands is a floating point number, the result will be a floating point number.

If both operands are integers, the result will be an integer.

'{{repl Sub (ConfigOption "maximum_users") 1}}'

Mult

func Mult(x interface{}, y interface{}) interface{}

Multiplies x and y.

Both operands must be either an integer or a floating point number.

If at least one of the operands is a floating point number, the result will be a floating point number.

If both operands are integers, the result will be an integer.

'{{repl Mult (NodePrivateIPAddressAll "DB" "redis" | len) 2}}'

If a template function returns a string, the value must be converted to an integer or a floating point number first:

'{{repl Mult (ConfigOption "session_cookie_age" | ParseInt) 86400}}'

Div

func Div(x interface{}, y interface{}) interface{}

Divides x by y.

If at least one of the operands is a floating point number, the result will be a floating point number.

If both operands are integers, the result will be an integer and will be rounded down.

'{{repl Div (ConfigOption "maximum_users") 2.0}}'

ParseBool

func ParseBool(str string) bool

ParseBool returns the boolean value represented by the string.

'{{repl ConfigOption "str_value" | ParseBool }}'

ParseFloat

func ParseFloat(str string) float64

ParseFloat returns the float value represented by the string.

'{{repl ConfigOption "str_value" | ParseFloat }}'

ParseInt

func ParseInt(str string, args ...int) int64

ParseInt returns the integer value represented by the string with optional base (default 10).

'{{repl ConfigOption "str_value" | ParseInt }}'

ParseUint

func ParseUint(str string, args ...int) uint64

ParseUint returns the unsigned integer value represented by the string with optional base (default 10).

'{{repl ConfigOption "str_value" | ParseUint }}'

TLSCert

func TLSCert(certName string, cn string, ips []interface{}, alternateDNS []interface{}, daysValid int) string

TLSCert generates and returns a self-signed certificate identified by certName.
The first parameter can be used in the TLSKey function to retrieve the matching key.

TLSCert takes the following parameters

• Unique name that identifies the certificate.
  This is a not a part of the returned certificate.
• Subject’s common name (cn)
• Optional list of IPs; may be nil
• Optional list of alternate DNS names; may be nil
• Cert validity duration in days

repl{{ TLSCert "my_custom_cert" "foo.com" (list "10.0.0.1" "10.0.0.2") (list "bar.com" "bat.com") 365 }}

TLSKey

func TLSKey(certName string, cn string, ips []interface{}, alternateDNS []interface{}, daysValid int) string

TLSKey returns the key that matches the certificate identified by certName.
The rest of the arguments are the same as in TLSCert and, if specified, must have the same values.
If they are omitted and the certificate with this name does not exist, the function will return an empty string.

repl{{ TLSKey "my_custom_cert" "foo.com" (list "10.0.0.1" "10.0.0.2") (list "bar.com" "bat.com") 365 }}

TLSCACert

func TLSCACert(caName string, daysValid int) string

TLSCACert generates and returns a CA certificate that can be used as a CA to sign other certificates.

TLSCACert takes the following parameters

• Subject’s common name (cn)
• Cert validity duration in days

repl{{ TLSCACert "foo.com" 365 }}

TLSCertFromCA

func TLSCertFromCA(caName string, certName string, cn string, ips []interface{}, alternateDNS []interface{}, daysValid int) string

TLSCertFromCA generates and returns a certificate signed by the CA identified by caName.
The rest of the arguments are the same as in TLSCert.

repl{{ TLSCertFromCA "foo.com" "my_custom_cert" "bar.com" (list "10.0.0.1" "10.0.0.2") (list "bar.com" "bat.com") 365 }}

TLSKeyFromCA

func TLSKeyFromCA(caName string, certName string, cn string, ips []interface{}, alternateDNS []interface{}, daysValid int) string

TLSKeyFromCA generates and returns a key that matches the certificate returned by TLSCertFromCA.
The arguments are the same as in TLSCertFromCA and their values must match.

repl{{ TLSKeyFromCA "foo.com" "my_custom_cert" "bar.com" (list "10.0.0.1" "10.0.0.2") (list "bar.com" "bat.com") 365 }}

IsKurl

func IsKurl() bool

IsKurl returns true if running within a kurl-based installation.

repl{{ IsKurl }}

Distribution

func Distribution() string

Distribution returns the kubernetes distribution detected, such as kurl, openShift or eks.

repl{{ Distribution }}

NodeCount

func NodeCount() int

NodeCount returns the number of nodes detected within the kubernetes cluster.

repl{{ NodeCount }}

HTTPProxy

func HTTPProxy() string

HTTPProxy returns the address of the proxy that the Admin Console is configured to use.

repl{{ HTTPProxy }}

NoProxy

func NoProxy() string

NoProxy returns the comma-separated list of no-proxy addresses that the Admin Console is configured to use.

repl{{ NoProxy }}

KotsVersion

func KotsVersion() string

KotsVersion returns the current KOTS tag/version the Admin Console is using.

repl{{ KotsVersion }}

KotsVersion can be compared to semvers like follows:

repl{{KotsVersion | semverCompare ">= 1.19"}}

The above template function will return true if KotsVersion is greater than 1.19.

For more complex comparisons, please refer to sprig Semantic Version Functions