Dynamic Params

This package allows you to manage your parameters of any type, while allowing you to use different sources of data (now, only in-memory and cli arguments), scan them based on a pattern or iterate through them and apply a callback,

Current Version: 1.0

Tables of Contents

1. Import
2. Usage
   1. Quick Way
   2. Simple
   3. TypeConversion
   4. Reading from Args
   5. Compound Types
3. List of Methods
4. Concurrency
5. Change Log
6. Development

Import

go get github.com/mostafatalebi/dynamic-params

Usage

Create an instance, and then add your params:

Quick Way

To quickly accessing values without worrying or handling the errors, you can use Q methods. Each method found in this doc has a Q method corresponding to it. Q methods are good for ignoring errors because they only return the value (and in case of error, a zero-value of the type). If the method you want to use is GetAsString(), then it becomes QGetString()

To create an instance with Q method quickly, use:

dp := dynamic_params.QNewDynamicParams()
dp.Set("sample-param", 25)
v := dp.QGetInt("sample-param")

Note: dynamic_params.QNewDynamicParams() is like NewDyanmicParams but it also can be invoked without any params. Still, if you want to create dynamic params from argument list or pass mutex to the instance, you need to pass the parameters.

Simple

p := dyanmic_params.NewDyanmicParams(SrcNameInternal)
p.Set("sample-int", 55)
val := p.Get("sample-int")

TypeConversion

If you have saved an int value, and you want to get it as an int and not interface, you simple can use GetAs* group of functions, and for your use case, it is GetAsInt() func. Be careful to check for its errors.

p := dyanmic_params.DyanmicParams(SrcNameInternal)
p.Set("sample-int", 55)
val, err := p.GetAsInt("sample-int")

Reading from Args

If you want to deal with values from argument list, you must know that our SrcNameArgs currently support this format:

--name1=value --name2=value --other=otherValue ....

Upon creating an instance of DynamicParams, set source to SrcNameArgs and pass your array of arguments (os.Args).

p := dp.NewDynamicParams(dp.SrcNameArgs, []string{"--key=123456"})
v, err := p.GetStringAsInt("key")
assert.NoError(t, err)
assert.Equal(t, 123456, v)

To deal with args, it only supports returning values in string, int or bool types. If your arguments has a numeric value not starting with zero, you can get it as int, or if it has a value of "false", "true", "1" or "0", you can get it as bool. GetStringAs*() group of functions are used to convert special values of string to either int or bool.

p := dp.NewDynamicParams(dp.SrcNameArgs, []string{"--key=true"})
v, err := p.GetStringAsBool("key")
assert.NoError(t, err)
assert.Equal(t, true, v)

You can save a param of any value, and upon getting the value, you either can get the raw value for compound types (array, struct, map etc.) or if the value was scalar, you can use helper methods to get a converted value.

Compound Types

To deal with other values such as struct or map, you should simply get them as interface{} with Get() method and do the type conversion.

Examples:

struct

type CustomType struct {
    Name string
}
p := dp.NewDynamicParams(dp.SrcNameInternal)
p.Set("key", &CustomType{Name: "Robert"})
v := p.Get("key")
assert.NotNil(t, v)
r, ok := v.(*CustomType)
assert.True(t, ok)
if r != nil {
    assert.Equal(t, "Robert", r.Name)
}

List of Methods

Set Sets a key and a value.

Has Checks to see if a key exists or not.

Get Returns the raw value passed when using Set()

Count Returns the number of params

Scan Scans param based on a given regex pattern, and returns the matched collection or nil if none

Iterate Iterates over params and applies the given callback

GetAsString or QGetString() Tries to convert the value to string before returning, error if conversion fails.

GetAsQuotedString or GetQuotedString() Tries to convert the value to string, and removes any surrounding single and double quotations before returning, error if conversion fails.

GetAsInt or GetInt() Tries to convert the value to int before returning, error if conversion fails.

GetAsTimeDuration or QGetTimeDuration() Tries to convert the value to time.Duration before returning, error if conversion fails.

GetStringAsInt or QGetStringAsInt() Tries to convert a non-zero starting, numeric string value to int before returning, error if conversion fails.

GetStringAsTimeDuration or QGetStringAsTimeDuration() Tries to convert a duration string (1ms or 2h1m) to a time.Duration type using time.ParseDuration() function

GetStringAsBool or QGetStringAsBool() Tries to convert a non-zero starting, numeric string value to bool before returning, error if conversion fails.

GetAsInt32 or QGetInt32() Refer to GetAsInt()

GetAsInt64 or QGetInt64() Refer to GetAsInt()

GetAsInt8 or QGetInt8() Refer to GetAsInt()

GetAsInt16 or QGetInt16() Refer to GetAsInt()

GetAsBool or QGetBool() Tries to convert the value to bool before returning, error if conversion fails.

Concurrency

By default, the instance you create is not concurrent safe, and concurrent access to it leads to unexpected results, or in many cases, fatal panic (due to concurrent map read and write). To make it concurrent safe, pass a mutex to the instance in its creation time:

lock := &sync.Mutex{}
dp := dynamic_params.NewDynamicParams(SrcNameInternal, lock)
dp.Set("sample-param", 25)
v := dp.QGetInt("sample-param")

Change Log

1.0

• adding QMethods for quick use of methods

<= 0.7

• adding mutexes and lock for concurrency safety
• adding more methods to supports different go data types
• adding basic methods and supporting CLI argument lists
• adding iteration and scanning of params

Development

Upcoming features:

• Plan to support redis as a data source
• Plan to support mongo as a data source
• Plan to support JSON string as a data source
• Plan to add JSON marshalling and unmarshalling