Fetch and decode Data Streams reports using the Go SDK

Guide Versions

This guide is available in multiple versions. Choose the one that matches your needs.

In this tutorial, you'll learn how to use the Data Streams SDK for Go to fetch and decode reports from the Data Streams Aggregation Network. You'll set up your Go project, retrieve reports, decode them, and log their attributes.

Requirements

Git: Make sure you have Git installed. You can check your current version by running git --version in your terminal and download the latest version from the official Git website if necessary.
Go Version: Make sure you have Go version 1.21 or higher. You can check your current version by running go version in your terminal and download the latest version from the official Go website if necessary.
API Credentials: Access to Data Streams requires API credentials. If you haven't already, contact us to request mainnet or testnet access.

Tutorial

You'll start with the set up of your Go project, installing the SDK and pasting example code. This will let you decode reports for both single and multiple streams, logging their attributes to your terminal.

Set up your Go project

Create a new directory for your project and navigate to it:

mkdir my-data-streams-project
cd my-data-streams-project

Initialize a new Go module:
```
go mod init my-data-streams-project
```

Install the Data Streams SDK:

go get github.com/smartcontractkit/data-streams-sdk/go

Fetch and decode a report with a single stream

Create a new Go file, single-stream.go, in your project directory:
```
touch single-stream.go
```

Insert the following code example and save your single-stream.go file:

package main

import (
    "context"
    "fmt"
    "os"
    "time"

    streams "github.com/smartcontractkit/data-streams-sdk/go"
    feed "github.com/smartcontractkit/data-streams-sdk/go/feed"
    report "github.com/smartcontractkit/data-streams-sdk/go/report"
    // NOTE: Use the report version (v3, v8, etc.) that matches your stream
    v3 "github.com/smartcontractkit/data-streams-sdk/go/report/v3"
)

func main() {
    // Validate command-line arguments
    if len(os.Args) < 2 {
        fmt.Printf("Usage: go run main.go [FeedID]\nExample: go run main.go 0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782\n")
        os.Exit(1)
    }
    feedIDInput := os.Args[1]

    // Get API credentials from environment variables
    apiKey := os.Getenv("API_KEY")
    apiSecret := os.Getenv("API_SECRET")
    if apiKey == "" || apiSecret == "" {
        fmt.Printf("API_KEY and API_SECRET environment variables must be set\n")
        os.Exit(1)
    }

    // Define the configuration for the SDK client
    cfg := streams.Config{
        ApiKey:    apiKey,
        ApiSecret: apiSecret,
        RestURL:   "https://api.testnet-dataengine.chain.link",
        Logger:    streams.LogPrintf,
    }

    // Initialize the SDK client
    client, err := streams.New(cfg)
    if err != nil {
        cfg.Logger("Failed to create client: %v\n", err)
        os.Exit(1)
    }

    // Create context with timeout
    ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
    defer cancel()

    // Parse the feed ID
    var feedID feed.ID
    if err := feedID.FromString(feedIDInput); err != nil {
        cfg.Logger("Invalid feed ID format '%s': %v\n", feedIDInput, err)
        os.Exit(1)
    }

    // Fetch the latest report
    reportResponse, err := client.GetLatestReport(ctx, feedID)
    if err != nil {
        cfg.Logger("Failed to get latest report: %v\n", err)
        os.Exit(1)
    }

    // Log the raw report data
    cfg.Logger("Raw report data: %+v\n", reportResponse)

    // Decode the report
    // NOTE: Use the report version (v3, v8, etc.) that matches your stream
    decodedReport, err := report.Decode[v3.Data](reportResponse.FullReport)
    if err != nil {
        cfg.Logger("Failed to decode report: %v\n", err)
        os.Exit(1)
    }

    // Format and display the decoded report
    // NOTE: Adjust for your report and desired output
    fmt.Printf("\nDecoded Report for Stream ID %s:\n"+
        "------------------------------------------\n"+
        "Observations Timestamp: %d\n"+
        "Benchmark Price       : %s\n"+
        "Bid                   : %s\n"+
        "Ask                   : %s\n"+
        "Valid From Timestamp  : %d\n"+
        "Expires At            : %d\n"+
        "Link Fee              : %s\n"+
        "Native Fee            : %s\n"+
        "------------------------------------------\n",
        feedIDInput,
        decodedReport.Data.ObservationsTimestamp,
        decodedReport.Data.BenchmarkPrice.String(),
        decodedReport.Data.Bid.String(),
        decodedReport.Data.Ask.String(),
        decodedReport.Data.ValidFromTimestamp,
        decodedReport.Data.ExpiresAt,
        decodedReport.Data.LinkFee.String(),
        decodedReport.Data.NativeFee.String(),
    )
}

Download the required dependencies and update the go.mod and go.sum files:
```
go mod tidy
```
Set up your API credentials as environment variables:
```
export API_KEY="<YOUR_API_KEY>"
export API_SECRET="<YOUR_API_SECRET>"
```
Replace <YOUR_API_KEY> and <YOUR_API_SECRET> with your actual credentials.

The Go script uses os.Getenv("API_KEY") and os.Getenv("API_SECRET") in its streams.Config to read these values. From the code sample above:
```
cfg := streams.Config{
    ApiKey:    os.Getenv("API_KEY"),
    ApiSecret: os.Getenv("API_SECRET"),
    RestURL:   "https://api.testnet-dataengine.chain.link",
    Logger: streams.LogPrintf,
}
```
This configuration also specifies the RestURL, which the base URL for the API. In this case, it is already set to the testnet URL for Data Streams.

See the SDK Reference page for more configuration options.

Read from a testnet crypto stream. The below example executes the application, reading from the ETH/USD crypto stream:

go run single-stream.go 0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782

Expect output similar to the following in your terminal:

Raw report data: {"fullReport":"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","feedID":"0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782","validFromTimestamp":1734216283,"observationsTimestamp":1734216283}

Decoded Report for Stream ID 0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782:
------------------------------------------
Observations Timestamp: 1734216283
Benchmark Price       : 3865052126782320350000
Bid                   : 3864985478146740000000
Ask                   : 3865140837060103650000
Valid From Timestamp  : 1734216283
Expires At            : 1734302683
Link Fee              : 3379350941986000
Native Fee            : 25872872271800
------------------------------------------

Your application has successfully decoded the report data.

Learn more about the decoded report details.

Fetch and decode reports for multiple streams

Create a new Go file, multiple-streams.go, in your project directory:
```
touch multiple-streams.go
```

Insert the following code example in your multiple-streams.go file:

package main

import (
    "context"
    "fmt"
    "os"
    "time"

    streams "github.com/smartcontractkit/data-streams-sdk/go"
    feed "github.com/smartcontractkit/data-streams-sdk/go/feed"
    report "github.com/smartcontractkit/data-streams-sdk/go/report"
    // NOTE: Use the report version (v3, v8, etc.) that matches your stream
    v3 "github.com/smartcontractkit/data-streams-sdk/go/report/v3"
)

func main() {
    // Validate command-line arguments
    if len(os.Args) < 3 {
        fmt.Printf("Usage: go run multiple-streams.go [StreamID1] [StreamID2] ...\n"+
            "Example: go run multiple-streams.go "+
            "0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782 "+
            "0x00036fe43f87884450b4c7e093cd5ed99cac6640d8c2000e6afc02c8838d0265\n")
        os.Exit(1)
    }

    // Get API credentials from environment variables
    apiKey := os.Getenv("API_KEY")
    apiSecret := os.Getenv("API_SECRET")
    if apiKey == "" || apiSecret == "" {
        fmt.Printf("API_KEY and API_SECRET environment variables must be set\n")
        os.Exit(1)
    }

    // Define the configuration for the SDK client
    cfg := streams.Config{
        ApiKey:    apiKey,
        ApiSecret: apiSecret,
        RestURL:   "https://api.testnet-dataengine.chain.link",
        Logger:    streams.LogPrintf,
    }

    // Initialize the SDK client
    client, err := streams.New(cfg)
    if err != nil {
        cfg.Logger("Failed to create client: %v\n", err)
        os.Exit(1)
    }

    // Create context with timeout
    ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
    defer cancel()

    // Parse Feed IDs
    var ids []feed.ID
    for _, arg := range os.Args[1:] {
        var fid feed.ID
        if err := fid.FromString(arg); err != nil {
            cfg.Logger("Invalid feed ID format '%s': %v\n", arg, err)
            continue
        }
        ids = append(ids, fid)
    }

    if len(ids) == 0 {
        cfg.Logger("No valid feed IDs provided\n")
        os.Exit(1)
    }

    // Fetch reports for all streams
    timestamp := uint64(time.Now().Unix())
    reportResponses, err := client.GetReports(ctx, ids, timestamp)
    if err != nil {
        cfg.Logger("Failed to get reports: %v\n", err)
        os.Exit(1)
    }

    // Process reports
    for _, reportResponse := range reportResponses {
        // Log the raw report data
        cfg.Logger("Raw report data for Stream ID %s: %+v\n",
            reportResponse.FeedID.String(), reportResponse)

        // Decode the report
        decodedReport, err := report.Decode[v3.Data](reportResponse.FullReport)
        if err != nil {
            cfg.Logger("Failed to decode report for Stream ID %s: %v\n",
                reportResponse.FeedID.String(), err)
            continue // Skip to next report if decoding fails
        }

        // Format and display the decoded report
        // NOTE: Adjust for your report and desired output
        fmt.Printf("\nDecoded Report for Stream ID %s:\n"+
            "------------------------------------------\n"+
            "Observations Timestamp: %d\n"+
            "Benchmark Price       : %s\n"+
            "Bid                   : %s\n"+
            "Ask                   : %s\n"+
            "Valid From Timestamp  : %d\n"+
            "Expires At            : %d\n"+
            "Link Fee              : %s\n"+
            "Native Fee            : %s\n"+
            "------------------------------------------\n",
            reportResponse.FeedID.String(),
            decodedReport.Data.ObservationsTimestamp,
            decodedReport.Data.BenchmarkPrice.String(),
            decodedReport.Data.Bid.String(),
            decodedReport.Data.Ask.String(),
            decodedReport.Data.ValidFromTimestamp,
            decodedReport.Data.ExpiresAt,
            decodedReport.Data.LinkFee.String(),
            decodedReport.Data.NativeFee.String(),
        )
    }
}

Before running the example, verify that your API credentials are still set in your current terminal session:
```
echo $API_KEY
echo $API_SECRET
```
If the commands above don't show your credentials, set them again:
```
export API_KEY="<YOUR_API_KEY>"
export API_SECRET="<YOUR_API_SECRET>"
```

Read from two testnet crypto streams. For this example, you will read from the ETH/USD and LINK/USD Data Streams crypto streams. Run your application:

go run multiple-streams.go 0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782 0x00036fe43f87884450b4c7e093cd5ed99cac6640d8c2000e6afc02c8838d0265

Expect to see the output below in your terminal:

2024-12-14T17:49:06-05:00 Raw report data for Stream ID 0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782: {"fullReport":"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","feedID":"0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782","validFromTimestamp":1734216545,"observationsTimestamp":1734216545}


Decoded Report for Stream ID 0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782:
------------------------------------------
Observations Timestamp: 1734216545
Benchmark Price       : 3862606619881446500000
Bid                   : 3862530109428509500000
Ask                   : 3862826368095386900000
Valid From Timestamp  : 1734216545
Expires At            : 1734302945
Link Fee              : 3401024329593900
Native Fee            : 25889252994400
------------------------------------------
2024-12-14T17:49:06-05:00 Raw report data for Stream ID 0x00036fe43f87884450b4c7e093cd5ed99cac6640d8c2000e6afc02c8838d0265: {"fullReport":"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","feedID":"0x00036fe43f87884450b4c7e093cd5ed99cac6640d8c2000e6afc02c8838d0265","validFromTimestamp":1734216545,"observationsTimestamp":1734216545}


Decoded Report for Stream ID 0x00036fe43f87884450b4c7e093cd5ed99cac6640d8c2000e6afc02c8838d0265:
------------------------------------------
Observations Timestamp: 1734216545
Benchmark Price       : 29402662200351580000
Bid                   : 29396857712545605000
Ask                   : 29408052824047658500
Valid From Timestamp  : 1734216545
Expires At            : 1734302945
Link Fee              : 3401052575395900
Native Fee            : 25889085213700
------------------------------------------

Your application has successfully fetched and decoded data for both streams.

Learn more about the decoded report details.

Decoded report details

The decoded crypto v3 report details include:

Attribute	Value	Description
Stream ID	`0x000359843a543ee2fe414dc14c7e7920ef10f4372990b79d6361cdc0dd1ba782`	The unique identifier for the stream. In this example, the stream is for ETH/USD.
Observations Timestamp	`1734216283`	The timestamp indicating when the data was captured.
Benchmark Price	`3865052126782320350000`	The observed price in the report, with 18 decimals. For readability: `3,865.0521267823204` USD per ETH.
Bid	`3864985478146740000000`	The highest price a buyer is willing to pay for an asset, with 18 decimals. For readability: `3,864.9854781467400` USD per ETH. Learn more about the Bid price. (For DEX State Price streams, this value equals `Benchmark Price`.)
Ask	`3865140837060103650000`	The lowest price a seller is willing to accept for an asset, with 18 decimals. For readability: `3,865.1408370601037` USD per ETH. Learn more about the Ask price. (For DEX State Price streams, this value equals `Benchmark Price`.)
Valid From Timestamp	`1734216283`	The start validity timestamp for the report, indicating when the data becomes relevant.
Expires At	`1734302683`	The expiration timestamp of the report, indicating the point at which the data becomes outdated.
Link Fee	`3379350941986000`	The fee to pay in LINK tokens for the onchain verification of the report data. With 18 decimals. For readability: `0.03379350941986` LINK. Note: This example fee is not indicative of actual fees.
Native Fee	`25872872271800`	The fee to pay in the native blockchain token (e.g., ETH on Ethereum) for the onchain verification of the report data. With 18 decimals. Note: This example fee is not indicative of actual fees.

For descriptions and data types of other report schemas, see the Report Schema Overview.

Payload for onchain verification

In this tutorial, you logged and decoded the full_report payloads to extract the report data. However, in a production environment, you should verify the data to ensure its integrity and authenticity.

Refer to the Verify report data onchain tutorial to learn more.

Adapting code for different report schema versions

When working with different versions of Data Stream reports, you'll need to adapt your code to handle the specific report schema version they use:

Import the correct schema version. Examples:

For v3 schema (as used in this example):

v3 "github.com/smartcontractkit/data-streams-sdk/go/report/v3"

For v8 schema:

v8 "github.com/smartcontractkit/data-streams-sdk/go/report/v8"

Update the decode function to use the correct schema version. Examples:

For v3 schema (as used in this example):

decodedReport, err := report.Decode[v3.Data](reportResponse.FullReport)

For v8 schema:

decodedReport, err := report.Decode[v8.Data](reportResponse.FullReport)

Access fields according to the schema version structure. Refer to the Report Schemas documentation for complete field references for each version.

Explanation

Initializing the client and configuration

The Data Streams client is initialized in two steps:

Configure the client with streams.Config:
```
cfg := streams.Config{
    ApiKey:    os.Getenv("API_KEY"),
    ApiSecret: os.Getenv("API_SECRET"),
    RestURL:   "https://api.testnet-dataengine.chain.link",
    Logger:    streams.LogPrintf,
}
```
The configuration requires:
- ApiKey and ApiSecret for authentication (required)
- RestURL for the API endpoint (required)
- Logger for debugging and error tracking (optional, defaults to streams.LogPrintf)
See the SDK Reference page for more configuration options.
Create the client with streams.New:
```
client, err := streams.New(cfg)
```
The client handles:
- Authentication with HMAC signatures
- Connection management and timeouts
- Error handling and retries

Fetching reports

The SDK provides two main methods to fetch reports:

Latest report for a single stream with GetLatestReport:
```
reportResponse, err := client.GetLatestReport(ctx, feedID)
```
- Takes a context and feed ID
- Returns a single ReportResponse with the most recent data
- No timestamp parameter needed
- Useful for real-time price monitoring
Latest reports for multiple streams with GetReports:
```
reportResponses, err := client.GetReports(ctx, ids, timestamp)
```
- Takes context, feed IDs array, and Unix timestamp
- Returns array of ReportResponse, one per feed ID
- Timestamp determines the point in time for the reports
- Efficient for monitoring multiple assets simultaneously

Each API request automatically:

Handles authentication with API credentials
Manages request timeouts via context
Processes responses into structured types

Decoding reports

Reports are decoded in two steps:

Report decoding with report.Decode:
```
decodedReport, err := report.Decode[v3.Data](reportResponse.FullReport)
```
This step:
1. Takes the raw FullReport bytes from the response
2. Uses v3.Data schema for Crypto streams (use the appropriate schema for your stream)
3. Validates the format and decodes using Go generics
4. Returns a structured report with typed data

Data access:

data := decodedReport.Data
price := data.BenchmarkPrice.String()  // Convert big number to string
bid := data.Bid.String()
ask := data.Ask.String()
validFrom := data.ValidFromTimestamp  // Unix timestamp
expiresAt := data.ExpiresAt          // Unix timestamp
// ...additional or different fields depending on the report schema

Provides access to:

Benchmark price, bid, and ask prices (as big numbers)
- Note: For DEX State Price streams, which also use the V3 schema, the bid and ask fields contain the same value as BenchmarkPrice.
Fee information (LINK and native token fees)
Timestamp data (validity period)
All numeric values require .String() for display

Error handling

The SDK uses Go's standard error handling patterns with some enhancements:

Context management:
```
ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()
```
- Sets request timeouts for API calls
- defer cancel() ensures cleanup of resources
- Same context pattern for both single and multiple reports

Error checking:

if err != nil {
    cfg.Logger("Failed to decode report: %v\n", err)
    os.Exit(1)           // Fatal errors: exit the program
    // or
    continue            // Non-fatal errors: skip this report
}

Fatal errors (client creation, no valid feeds) use os.Exit(1)
Non-fatal errors (single report decode) use continue
All errors are logged before handling

SDK logging:
```
cfg.Logger("Raw report data: %+v\n", reportResponse)
```
- Uses configured logger for SDK operations
- fmt.Printf for user-facing output
- Debug information includes raw report data
- Structured error messages with context

The decoded data can be used for further processing or display in your application. For production environments, you must verify the data onchain using the provided fullReport payload.

Fetch and decode Data Streams reports using the Go SDK

Guide Versions

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