LightningProgressRing component

progressRing.cmp

<aura:component >
    <aura:attribute name="value" type="Integer" default="0" />
    <aura:attribute name="variant" type="String" />

    <aura:attribute name="hasVariant" type="Boolean" access="private" default="{!false}" />
    <aura:attribute name="ringClass" type="String" access="private" />
    <aura:attribute name="iconName" type="String" access="private" />
    <aura:attribute name="altText" type="String" access="private" />
    
    <aura:handler name="init" value="{!this}" action="{!c.updateView}" />
    <aura:handler name="change" value="{!v.value}" action="{!c.updateView}" />
    <aura:handler name="change" value="{!v.variant}" action="{!c.updateView}" />

    <div class="{!v.ringClass}">
        <div id="progressContainer" class="slds-progress-ring__progress" role="progressbar" aria-valuemin="0" aria-valuemax="100" aria-valuenow="{!v.value}">
            
        </div>
        <div class="slds-progress-ring__content">
            <aura:if isTrue="{!v.hasVariant}">
                <lightning:icon iconName="{!v.iconName}" size="xx-small" title="{!v.altText}" alternativeText="{!v.altText}" />
            </aura:if>
        </div>
    </div>
</aura:component>

progressRingController.js

({
	updateView: function(component, event, helper) {
        var variant = component.get("v.variant"),
            hasVariant = variant == "warning" || variant == "expired",
            style = "slds-progress-ring",
            iconName,
            altText;
        if(hasVariant) {
            style = style + " " + style + "_" + variant;
            iconName = "utility:"+({ warning: "warning", expired: "error" }[variant]);
            altText = { warning: "Warning", expired: "Expired" }[variant];
        }
        component.set("v.ringClass", style);
        component.set("v.hasVariant", hasVariant);
        component.set("v.iconName", iconName);
        component.set("v.altText", altText)
    }
})

progressRingRenderer.js

({
    // Create SVG, path, populate with default values from controller
    render: function(component, helper) {
        var result = this.superRender(),
            xmlns = "http://www.w3.org/2000/svg",
            updateContainer = result[0].querySelector("#progressContainer"),
            value = component.get("v.value"),
            dValue = "M 1 0 A 1 1 0 "+Math.floor(value / 50)+" 1 "+
                Math.cos(2 * Math.PI * value / 100)+" "+
                Math.sin(2 * Math.PI * value / 100)+" L 0 0",
            svg = document.createElementNS(xmlns,"svg"),
            path = document.createElementNS(xmlns,"path");
        svg.setAttributeNS(null,"viewBox", "-1 -1 2 2");
        path.setAttributeNS(null, "class", "slds-progress-ring__path");
        path.setAttributeNS(null, "d", dValue);
        svg.appendChild(path);
        updateContainer.appendChild(svg);
        return result;
    },
    // Update the progress bar on a rerender event
    rerender: function(component, helper) {
        var value = component.get("v.value"),
            dValue = "M 1 0 A 1 1 0 "+Math.floor(value / 50)+" 1 "+
                Math.cos(2 * Math.PI * value / 100)+" "+
                Math.sin(2 * Math.PI * value / 100)+" L 0 0",
            svg = component.getElement().querySelector("svg"),
            path = svg.childNodes[0];
        this.superRerender();
        path.setAttributeNS(null, "d", dValue);
    }
})