Slack

Slack is one of the most popular chat platforms, and is great to build bots and notifications when things happen on chain.

Setup a bot on slack

Go to api.slack.com, log into your workspace and click on Create an app
Click on From scratch and then give it a name and select your workspace. We will call ours RethTransferEvents.
Click on the Bots box under the Add features and functionality header
Click on Review scopes to add
Scroll down to the Bot token scopes header and add chat:write. These are the permissions the bot needs to write messages
Finally, scroll all the way up and click on Install to workspace, and Allow on the following screen. This should now show a screen with the Bot User OAuth Token visible. Take note of this token, since it’s the one we will be using to send messages.
Now add the bot to the channel you want to send a message to, channels are the # followed by the channel name. You need to include the # in the channel name.

Configure rindexer

slack property accepts an array allowing you to split up the channels any way you wish.

Example

contract events

name: RocketPoolETHIndexer
description: My first rindexer project
repository: https://github.com/joshstevens19/rindexer
project_type: no-code
networks:
- name: ethereum
  chain_id: 1
  rpc: https://mainnet.gateway.tenderly.co
contracts:
- name: RocketPoolETH
  details:
  - network: ethereum
    address: "0xae78736cd615f374d3085123a210448e74fc6393"
    start_block: "18600000"
    end_block: "18600181"
  abi: "./abis/RocketTokenRETH.abi.json"
  include_events:
  - Transfer
  chat: 
    slack: 
      - bot_token: ${SLACK_BOT_TOKEN}
        channel: "#RethTransferEvents"
        networks: 
          - ethereum
        messages:
          - event_name: Transfer
            # filter_expression is optional
            filter_expression: "from = '0x0338ce5020c447f7e668dc2ef778025ce3982662' || from = '0x0338ce5020c447f7e668dc2ef778025ce398266u' && value >= 10 && value <= 2000000000000000000"
            template_inline: "*New RETH Transfer Event*
 
                              from: {{from}}
 
                              to: {{to}}
 
                              amount: {{format_value(value, 18)}}
 
                              RETH contract: {{transaction_information.address}}
 
                              <https://etherscan.io/tx/{{transaction_information.transaction_hash}} | etherscan>
                              "

bot_token

This is your slack bot token which you generate using @BotFather.

...
contracts:
- name: RocketPoolETH
  details:
  - network: ethereum
    address: "0xae78736cd615f374d3085123a210448e74fc6393"
    start_block: "18600000"
    end_block: "18600181"
  abi: "./abis/RocketTokenRETH.abi.json"
  include_events:
  - Transfer
  chat: 
    slack: 
      - bot_token: ${SLACK_BOT_TOKEN}

channel

This is the channel you want to send messages to.

...
contracts:
- name: RocketPoolETH
  details:
  - network: ethereum
    address: "0xae78736cd615f374d3085123a210448e74fc6393"
    start_block: "18600000"
    end_block: "18600181"
  abi: "./abis/RocketTokenRETH.abi.json"
  include_events:
  - Transfer
  chat: 
    slack: 
      - bot_token: ${SLACK_BOT_TOKEN}
        channel: "#RethTransferEvents"

networks

This is an array of networks you want to send messages to this slack channel.

rindexer.yaml

...
contracts:
- name: RocketPoolETH
  details:
  - network: ethereum
    address: "0xae78736cd615f374d3085123a210448e74fc6393"
    start_block: "18600000"
    end_block: "18600181"
  abi: "./abis/RocketTokenRETH.abi.json"
  include_events:
  - Transfer
  chat: 
    slack: 
      - bot_token: ${SLACK_BOT_TOKEN}
        channel: "#RethTransferEvents"
        networks: 
          - ethereum

messages

This is an array of messages you want to send to this slack channel. It is an array as you can define many different messages to send to this channel with different conditions.

event_name

This is the name of the event you want to send a message for, must match the ABI event name.

rindexer.yaml

...
contracts:
- name: RocketPoolETH
  details:
  - network: ethereum
    address: "0xae78736cd615f374d3085123a210448e74fc6393"
    start_block: "18600000"
    end_block: "18600181"
  abi: "./abis/RocketTokenRETH.abi.json"
  include_events:
  - Transfer
  chat: 
    slack: 
      - bot_token: ${SLACK_BOT_TOKEN}
        channel: "#RethTransferEvents"
        networks:
          - ethereum
        messages:
          - event_name: Transfer

filter_expression

This accepts a filter expression to filter the events before sending a message to this discord channel

Filter expressions allow for condition checking of the event data and support logical operators to combine multiple conditions.

Supported types and operations:

Type	Description	Operators	Notes
Numeric (uint/int variants)	Integer values (e.g., `42`, `-100`) or decimal values (e.g., `3.14`, `-0.5`)	`>`, `<`, `=`, `>=`, `<=`	Numeric comparisons
Address	Ethereum addresses (e.g., `0x1234567890abcdef1234567890abcdef12345678`)	`=`, `!=`	Comparisons (e.g., `from == '0xABC...'`) are typically case-insensitive regarding the hex characters of the address value itself
String	Text values. Can be single-quoted (e.g., `'hello'`) or, on the right-hand side of a comparison, unquoted (e.g., `active`)	`=`, `!=`	Quoted strings support `\'` to escape a single quote and `\\` to escape a backslash. All string comparison operations (e.g., `name == 'Alice'`, `description contains 'error'`) are performed case-insensitively during evaluation.
Boolean	True or false values	`=`, `!=`	Represented as `true` or `false`. These keywords are parsed case-insensitively (e.g., `TRUE`, `False` are also valid in expressions).
Hex String Literal	A string literal starting with `0x` or `0X` followed by hexadecimal characters (0-9, a-f, A-F).	`=`, `!=`	Treated as a string for comparison purposes (e.g., `input_data starts_with '0xa9059cbb'`). Comparison is case-sensitive for the hex characters after `0x`.
Array	Ordered list of items	`==`, `!=`, `[index]`	See "Array Type Operations" below

Logical Operators

&& - All conditions must be true
|| - At least one condition must be true
() - Parentheses for grouping
&& has higher precedence than || (i.e., && operations are evaluated before || operations if not grouped by parentheses)

Array Type Operations

For array types, you can use the following operations:

array_param == '["raw_json_array_string"]' string comparison of the array's entire JSON string representation against the provided string
array_param != '["raw_json_array_string"]' the negation of the above
array_param[0] indexed access. The index must be a non-negative integer.

Whitespace

Flexible whitespace is generally allowed around operators, parentheses, and keywords for readability. However, whitespace within quoted string literals is significant and preserved.

Examples

value > 1000 - Numeric comparison, checks if value is greater than 1000.
from = '0x1234567890abcdef1234567890abcdef12345678' - Address comparison, checks if from matches the specified address.
name != 'Alice' - String comparison, checks if name is not equal to 'Alice'.
active = true - Boolean comparison, checks if active is true.
value >= 1000 && value <= 2000 - Numeric range check, checks if value is between 1000 and 2000 inclusive.
from = '0x1234567890abcdef1234567890abcdef12345678' || from = '0xabcdefabcdefabcdefabcdefabcdefabcdef' - Address comparison with logical OR, checks if from matches either of the two addresses.
value > 1000 && (from = '0x1234567890abcdef1234567890abcdef12345678' || from = '0xabcdefabcdefabcdefabcdefabcdefabcdef') - Combined numeric and address checks with logical AND and OR, checks if value is greater than 1000 and from matches either of the two addresses.

conditions

This accepts an array of conditions you want to apply to the event data before sending a message to this slack channel.

You may want to filter on the message based on the event data, if the event data has not got an index on the on the solidity event you can not filter it over the logs. The conditions filter is here to help you with this, based on your ABI you can filter on the event data.

rindexer has enabled a special syntax which allows you to define on your ABI fields what you want to filter on.

> - higher then (for numbers only)
< - lower then (for numbers only)
= - equals
>= - higher then or equals (for numbers only)
<= - lower then or equals (for numbers only)
|| - or
&& - and

So lets look at an example lets say i only want to get transfer events which are higher then 2000000000000000000 RETH wei

rindexer.yaml

...
contracts:
- name: RocketPoolETH
  details:
  - network: ethereum
    address: "0xae78736cd615f374d3085123a210448e74fc6393"
    start_block: "18600000"
    end_block: "18600181"
  abi: "./abis/RocketTokenRETH.abi.json"
  include_events:
  - Transfer
  chat: 
    slack: 
      - bot_token: ${SLACK_BOT_TOKEN}
        channel: "#RethTransferEvents"
        networks:
          - ethereum
        messages:
          - event_name: Transfer
            conditions: 
              - "value": ">=2000000000000000000"

We use the ABI input name value to filter on the value field, you can find these names in the ABI file.

{
    "anonymous":false,
    "inputs":[
      {
        "indexed":true,
        "internalType":"address",
        "name":"from",
        "type":"address"
      },
      {
        "indexed":true,
        "internalType":"address",
        "name":"to",
        "type":"address"
      },
      {
        "indexed":false,
        "internalType":"uint256",
        "name":"value", 
        "type":"uint256"
      }
    ],
    "name":"Transfer",
    "type":"event"
}

You can use the || or && to combine conditions.

rindexer.yaml

...
contracts:
- name: RocketPoolETH
  details:
  - network: ethereum
    address: "0xae78736cd615f374d3085123a210448e74fc6393"
    start_block: "18600000"
    end_block: "18600181"
  abi: "./abis/RocketTokenRETH.abi.json"
  include_events:
  - Transfer
  chat: 
    slack: 
      - bot_token: ${SLACK_BOT_TOKEN}
        channel: "#RethTransferEvents"
        networks:
          - ethereum
        messages:
          - event_name: Transfer
            conditions: 
              - "value": ">=2000000000000000000 && value <=4000000000000000000"

You can use the = to filter on other aspects like the from or to address.

rindexer.yaml

...
contracts:
- name: RocketPoolETH
  details:
  - network: ethereum
    address: "0xae78736cd615f374d3085123a210448e74fc6393"
    start_block: "18600000"
    end_block: "18600181"
  abi: "./abis/RocketTokenRETH.abi.json"
  include_events:
  - Transfer
  chat: 
    slack: 
      - bot_token: ${SLACK_BOT_TOKEN}
        channel: "#RethTransferEvents"
        networks:
          - ethereum
        messages:
          - event_name: Transfer
              conditions: 
                - "from": "0x0338ce5020c447f7e668dc2ef778025ce3982662 || 0x0338ce5020c447f7e668dc2ef778025ce398266u"
                - "value": ">=2000000000000000000 || value <=4000000000000000000"

If you have a tuple and you want to get that value you just use the object notation.

For example lets say we want to only get the events for profileId from the quoteParams tuple which equals 1:

{
     "anonymous": false,
     "inputs": [
       {
         "components": [
           {
             "internalType": "uint256",
             "name": "profileId", 
             "type": "uint256"
           },
           ...
         ],
         "indexed": false,
         "internalType": "struct Types.QuoteParams",
         "name": "quoteParams", 
         "type": "tuple"
       },
       ...
     ],
     "name": "QuoteCreated", 
     "type": "event"
}

rindexer.yaml

...
contracts:
- name: RocketPoolETH
  details:
  - network: ethereum
    address: "0xae78736cd615f374d3085123a210448e74fc6393"
    start_block: "18600000"
    end_block: "18600181"
  abi: "./abis/RocketTokenRETH.abi.json"
  include_events:
  - Transfer
  chat: 
    slack: 
      - bot_token: ${SLACK_BOT_TOKEN}
        channel: "#RethTransferEvents"
        networks:
          - ethereum
        messages:
          - event_name: Transfer
            conditions: 
              - "quoteParams.profileId": "=1"

template_inline

You can then write your own template inline, this is the template you want to send to the channel. You have to use the ABI input names in object notation for example if i wanted to put value in the template i just have to write {{value}} in the template and it will be replaced with the value of the event itself.

The template supports:

bold text = *bold text*
italic text = _italic text_
strikethrough text = ~strikethrough text~
block qoute = > block quote
inline url = <URL | etherscan>
inline fixed-width code = `inline fixed-width code`
pre-formatted fixed-width code block = ```pre-formatted fixed-width code block```
pre-formatted fixed-width known code block = ```rust pre-formatted fixed-width known code block```
breaks = just line break in the template

transaction_information

You also can use the transaction_information object to get common information about the transaction, this is the transaction information for the event.

#[derive(Debug, Serialize, Deserialize, Clone)]
pub struct TxInformation {
    pub network: String,
    // This will convert to a hex string in the template
    pub address: Address,
    // This will convert to a hex string in the template
    pub block_hash: BlockHash,
    // This will convert to a string decimal in the template
    pub block_number: U64,
    // This will convert to a hex string in the template
    pub transaction_hash: TxHash,
    // This will convert to a string decimal in the template
    pub log_index: U256,
    // This will convert to a string decimal in the template
    pub transaction_index: U64,
}

format_value

You can use the format_value function to format the value of the event to a decimal value with the specified decimals.

Lets put it all together:

rindexer.yaml

...
contracts:
- name: RocketPoolETH
  details:
  - network: ethereum
    address: "0xae78736cd615f374d3085123a210448e74fc6393"
    start_block: "18600000"
    end_block: "18600181"
  abi: "./abis/RocketTokenRETH.abi.json"
  include_events:
  - Transfer
  chat: 
    slack: 
      - bot_token: ${SLACK_BOT_TOKEN}
        channel: "#RethTransferEvents"
        networks:
          - ethereum
        messages:
          - event_name: Transfer
            template_inline: "*New RETH Transfer Event*
 
                              from: {{from}}
 
                              to: {{to}}
 
                              amount: {{format_value(value, 18)}}
 
                              RETH contract: {{transaction_information.address}}
 
                              <https://etherscan.io/tx/{{transaction_information.transaction_hash}} | etherscan>
                              "