flow

A flow allows visualization of queries using types such as sankey. Flows are node/edge visualizations. The data to be displayed is specified using a series of nodes and edges. The nodes define the vertices of the graph, and the edges define the connections between them.

Flow blocks can be declared as named resources at the top level of a mod, or they can be declared as anonymous blocks inside a dashboard or container, or be re-used inside a dashboard or container by using a flow with base = <mod>.flow.<flow_resource_name>.

Example Usage

dashboard "flow_sankey_ex_1" {

  input "vpc_input" {
    width = 4

    sql = <<-EOQ
      select
        title as label,
        vpc_id as value
      from
        aws_vpc
    EOQ
  }

  flow {
    title = "AWS VPC Subnets by AZ"

    node {
      sql = <<-EOQ
        select
          vpc_id as id,
          vpc_id as title
        from
          aws_vpc
        where
          vpc_id = $1
      EOQ

      args = [self.input.vpc_input.value]
    }


    node {
      sql = <<-EOQ
        select
          distinct on (availability_zone)
          availability_zone as id,
          availability_zone as title
        from
          aws_vpc_subnet
        where
          vpc_id = $1
      EOQ

      args = [self.input.vpc_input.value]
    }

    node {
      sql = <<-EOQ
        select
          subnet_id as id,
          subnet_id as title
        from
          aws_vpc_subnet
        where
          vpc_id = $1
      EOQ

      args = [self.input.vpc_input.value]
    }

    edge {
      sql = <<-EOQ
        select
          distinct on (availability_zone)
          vpc_id as from_id,
          availability_zone as to_id
        from
          aws_vpc_subnet
        where
          vpc_id = $1
      EOQ

      args = [self.input.vpc_input.value]
      
    }

    edge {
      sql = <<-EOQ
        select
          availability_zone as from_id,
          subnet_id as to_id
        from
          aws_vpc_subnet
        where
          vpc_id = $1
      EOQ
      args = [self.input.vpc_input.value]
    }
  }

}

Argument Reference

Argument	Type	Optional?	Description
`args`	Map	Optional	A map of arguments to pass to the query.
`base`	flow Reference	Optional	A reference to a named `flow` resource that this `flow` should source its definition from. `title` and `width` can be overridden after sourcing via `base`.
`category`	Block	Optional	category blocks that specify display options for nodes with that category.
`database`	String	Optional	A database connection string for the database you wish to query. If not specified, the active database will be used.
`edge`	Block	Optional	edge blocks that define the edges in the flow.
`node`	Block	Optional	node blocks that define the nodes in the flow.
`param`	Block	Optional	param blocks that defines the parameters that can be passed in to the query. `param` blocks may only be specified for hierarchies that specify the `sql` argument.
`query`	Query Reference	Optional	A reference to a query resource that defines the query to run. A `flow` may either specify the `query` argument or the `sql` argument, but not both.
`sql`	String	Optional	An SQL string to provide data for the `flow`. A `flow` may either specify the `query` argument or the `sql` argument, but not both.
`--search-path`	String	Optional	Set a comma-separated list of connections to use as a custom search path for the query
`--search-path-prefix`	String	Optional	Set a comma-separated list of connections to use as a prefix to the current search path for the query.
`title`	String	Optional	A plain text title to display for this flow.
`type`	String	Optional	The type of the flow. Can be `sankey` or `table`.
`width`	Number	Optional	The width as a number of grid units that this item should consume from its parent.
`with`	Block	Optional	with blocks that define prerequisite queries to run. `with` blocks may only be specified when the flow is defined as a top-level (mod level), named resource.

Common Flow Properties

Property	Type	Default	Values	Description
`color`	string	The matching color from the default theme for the data series index.	A valid color value. This may be a named color, RGB or RGBA string, or a control status color.	The color to display for this category.

Data Format

Flow data must be provided in a format where each row represents a node (vertex), an edge (connecting 2 vertices), or both.

Note that both column names and their relative position are important in flow queries; Powerpipe looks for columns by name in the result set, but Postgres union queries will append the rows based on the column's position, not the name of the column. All the union queries must return the same columns, in the same order.

Significant columns are:

Name	Description
`id`	A unique identifier for the node. Nodes have an `id`, edges do not.
`title`	A title to display for the node.
`category`	A display category name. Both nodes and edges may specify a `category` to dictate how the item is displayed. By default, items of the same category are displayed with the same appearance (color), distinct from other categories. You can specify display options with a category block.
`depth`	An integer to set the position of the node. The layout of the nodes is inferred from the query, however you can force placement with the `depth` column if you need to override the default behavior.
`from_id`	The `id` of the source side of an edge.
`to_id`	The `id` of the destination side of an edge.

Generally speaking, there are 2 data formats commonly used for flows. If the data is hierarchical, it is often simpler to specify results where each row species a node (with an id, and optionally title, category, and/or depth) and an edge, by specifying a from_id:

from_id	id	title	category
<null>	1	foo	root
1	2	bar	widget
1	3	baz	widget
2	4	foobar	fidget

For flows that do not conform to a single-parent hierarchical structure, it's' usually easier to specify nodes and edges as separate rows. In this case, nodes will have an id and optionally title, category, and/or depth, but to_id and from_id will be null. Edges will populate to_id and from_id and optionally category, and will have null id, depth, and title:

from_id	to_id	id	title	category
<null>	<null>	1	foo	root
<null>	<null>	2	bar	widget
<null>	<null>	3	baz	widget
<null>	<null>	4	foobar	fidget
1	2	<null>	<null>	widget
1	3	<null>	<null>	widget
2	4	<null>	<null>	fidget
3	4	<null>	<null>	fidget

More Examples

Sankey with color by category

dashboard "flow_sankey_ex_category" {

  input "vpc_input" {
    width = 4

    sql = <<-EOQ
      select
        title as label,
        vpc_id as value
      from
        aws_vpc
    EOQ
  }

  flow {
    title = "AWS VPC Subnets by AZ"

    node {
      category = category.aws_vpc

      sql = <<-EOQ
        select
          vpc_id as id,
          vpc_id as title
        from
          aws_vpc
        where
          vpc_id = $1
      EOQ

      args = [self.input.vpc_input.value]
    }


    node {
      category = category.aws_availability_zone

      sql = <<-EOQ
        select
          distinct on (availability_zone)
          availability_zone as id,
          availability_zone as title
        from
          aws_vpc_subnet
        where
          vpc_id = $1
      EOQ

      args = [self.input.vpc_input.value]
    }

    node {
      category = category.aws_vpc_subnet

      sql = <<-EOQ
        select
          subnet_id as id,
          subnet_id as title
        from
          aws_vpc_subnet
        where
          vpc_id = $1
      EOQ

      args = [self.input.vpc_input.value]
    }

    edge {
      sql = <<-EOQ
        select
          distinct on (availability_zone)
          vpc_id as from_id,
          availability_zone as to_id
        from
          aws_vpc_subnet
        where
          vpc_id = $1
      EOQ

      args = [self.input.vpc_input.value]
      
    }

    edge {
      sql = <<-EOQ
        select
          availability_zone as from_id,
          subnet_id as to_id
        from
          aws_vpc_subnet
        where
          vpc_id = $1
      EOQ
      args = [self.input.vpc_input.value]
    }
  }

}

category "aws_vpc" {
  color = "orange"
}

category "aws_availability_zone" {
  color = "tan"
}

category "aws_vpc_subnet" {
  color = "green"
}

sankey with monolithic query

dashboard "flow_sankey_ex_1_mono" {

  flow {
    type  = "sankey"
    title = "AWS VPC Subnets by AZ"

    sql = <<-EOQ

      with vpc as
        (select 'vpc-9d7ae1e7' as vpc_id)

      select
        null as from_id,
        vpc_id as id,
        vpc_id as title,
        0 as depth,
        'aws_vpc' as category
      from
        aws_vpc
      where
        vpc_id in (select vpc_id from vpc)

      union all
      select
        distinct on (availability_zone)
        vpc_id as from_id,
        availability_zone as id,
        availability_zone as title,
        1 as depth,
        'aws_availability_zone' as category
      from
        aws_vpc_subnet
      where
        vpc_id in (select vpc_id from vpc)


      union all
      select
        availability_zone as from_id,
        subnet_id as id,
        subnet_id as title,
        2 as depth,
        'aws_vpc_subnet' as category
      from
        aws_vpc_subnet
      where
        vpc_id in (select vpc_id from vpc)

    EOQ
  }
}

Sankey with color by category (monolithic query)

dashboard "flow_sankey_ex_category_mono" {

  flow {
    type  = "sankey"
    title = "AWS VPC Subnets by AZ"

    category "aws_vpc" {
      color = "orange"
    }

    category "aws_availability_zone" {
      color = "tan"
    }

      category "aws_vpc_subnet" {
      color = "green"
    }

    sql = <<-EOQ

      with vpc as
        (select 'vpc-9d7ae1e7' as vpc_id)

      select
        null as from_id,
        vpc_id as id,
        vpc_id as title,
        0 as depth,
        'aws_vpc' as category
      from
        aws_vpc
      where
        vpc_id in (select vpc_id from vpc)

      union all
      select
        distinct on (availability_zone)
        vpc_id as from_id,
        availability_zone as id,
        availability_zone as title,
        1 as depth,
        'aws_availability_zone' as category
      from
        aws_vpc_subnet
      where
        vpc_id in (select vpc_id from vpc)


      union all
      select
        availability_zone as from_id,
        subnet_id as id,
        subnet_id as title,
        2 as depth,
        'aws_vpc_subnet' as category
      from
        aws_vpc_subnet
      where
        vpc_id in (select vpc_id from vpc)

    EOQ
  }
}

Sankey with node/edge data format, color by category, depth

dashboard "flow_sankey_ex_2" {
  flow {
    type  = "sankey"
    title = "AWS IAM Managed Policies for User"

    category "direct" {
      color = "alert"
    }

    category "indirect" {
      color = "ok"
    }

    sql = <<-EOQ
      with user_list as
        (select 'arn:aws:iam::111111111111:user/jsmyth' as arn)

      -- User Nodes
      select
        arn as id,
        name as title,
        0 as depth,
        'user' as category,
        null as from_id,
        null as to_id
      from
        aws_iam_user
      where
        arn in (select arn from user_list)

      -- Group Nodes
      union select
        g ->> 'Arn' as id,
        g ->> 'GroupName' as title,
        1 as depth,
        'group' as category,
        null as from_id,
        null as to_id
      from
        aws_iam_user,
        jsonb_array_elements(groups) as g
      where
        arn in (select arn from user_list)


      -- Policy Nodes (attached to groups)
      union select
        p.arn as id,
        p.name as title,
        2 as depth,
        'policy' as category,
        null as from_id,
        null as to_id
      from
        aws_iam_user as u,
        jsonb_array_elements(groups) as g,
        aws_iam_group as grp,
        jsonb_array_elements_text(grp.attached_policy_arns) as pol_arn,
        aws_iam_policy as p
      where
        g ->> 'Arn' = grp.arn
        and pol_arn = p.arn
        and u.arn in (select arn from user_list)


      -- Policy Nodes (attached to user)
      union select
        p.arn as id,
        p.name as title,
        2 as depth,
        'policy' as category,
        null as from_id,
        null as to_id
      from
        aws_iam_user as u,
        jsonb_array_elements_text(attached_policy_arns) as pol_arn,
        aws_iam_policy as p
      where
        pol_arn = p.arn
        and u.arn in (select arn from user_list)

      -- User-> Group Edge
      union select
        null as id,
        null as title,
        null as depth,
        'indirect' as category,
        arn as from_id,
        g ->> 'Arn' as to_id
      from
        aws_iam_user,
        jsonb_array_elements(groups) as g
      where
        arn in (select arn from user_list)

      -- User -> Policy Edge
      union select
        null as id,
        null as title,
        null as depth,
        'direct' as category,
        arn as from_id,
        pol_arn
      from
        aws_iam_user,
        jsonb_array_elements_text(attached_policy_arns) as pol_arn
      where
        arn in (select arn from user_list)


    -- Group -> Policy Edge
      union select
        null as id,
        null as title,
        null as depth,
        'indirect' as category,
        grp.arn as from_id,
        pol_arn
      from
        aws_iam_user as u,
        jsonb_array_elements(groups) as g,
        aws_iam_group as grp,
        jsonb_array_elements_text(grp.attached_policy_arns) as pol_arn,
        aws_iam_policy as p
      where
        g ->> 'Arn' = grp.arn
        and pol_arn = p.arn
        and u.arn in (select arn from user_list)

    EOQ
  }
}