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Osmedeus uses a template engine for variable interpolation in workflows.

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Template Syntax

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Standard Variables: {{Variable}}

Double curly braces for standard variable interpolation: 
steps:
  - name: scan
    type: bash
    command: subfinder -d {{target}} -o {{Output}}/subdomains.txt

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Foreach Variables: [[variable]]

Double square brackets for foreach loop variables: 
steps:
  - name: probe-hosts
    type: foreach
    input: "{{Output}}/subdomains.txt"
    variable: subdomain
    step:
      name: httpx
      type: bash
      command: echo [[subdomain]] | httpx >> {{Output}}/live.txt
The [[]] syntax prevents conflicts between loop variables and template variables.

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Built-in Variables

VariableDescriptionExample Value
{{Target}}Current scan targetexample.com
{{TargetSpace}}Sanitized target (filesystem safe)example_com
{{Output}}Workspace output directory/home/user/osmedeus-base/workspaces/example.com
{{BaseFolder}}Osmedeus installation directory/home/user/osmedeus-base
{{Binaries}}Path to tool binaries/home/user/osmedeus-base/binaries
{{Data}}Path to data files/home/user/osmedeus-base/data
{{Workspaces}}Path to workspaces directory/home/user/osmedeus-base/workspaces
{{threads}}Thread count (based on tactic)50
{{baseThreads}}Base thread count25
{{TaskID}}Unique task identifierabc123
{{Today}}Current date (YYYY-MM-DD)2024-01-15
{{TimeStamp}}Unix timestamp1705312000
{{RandomString}}Random 8-character stringxK9mPq2r

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Variable Resolution

Variables are resolved in this order:
  1. Exports - Values from previous step exports
  2. Parameters - User-provided params (-p key=value)
  3. Built-in Variables - System-provided values
  4. Environment Variables - From shell environment
If not found, the variable renders as an empty string.

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Parameters

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Defining Parameters

params:
  - name: target
    required: true
    description: Target domain to scan

  - name: threads
    default: "10"
    description: Number of threads

  - name: wordlist
    default: "{{Data}}/wordlists/subdomains.txt"
    description: Path to wordlist

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Passing Parameters

CLI: 
# Single parameter
osmedeus run -m scan -t example.com -p 'threads=20'

# Multiple parameters
osmedeus run -m scan -t example.com -p 'threads=20' -p 'wordlist=/custom/list.txt'

# From file
osmedeus run -m scan -t example.com -P params.yaml
params.yaml: 
threads: "20"
wordlist: "/custom/list.txt"

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Using Parameters

steps:
  - name: scan
    type: bash
    command: subfinder -d {{target}} -t {{threads}} -w {{wordlist}}

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Generator Functions

Use generator functions in parameter defaults:
FunctionDescriptionExample
uuid()Generate UUID v4a1b2c3d4-...
currentDate()Current date (YYYY-MM-DD)2024-01-15
currentDate(format)Formatted datecurrentDate("02-Jan-2006")
currentTimestamp()Unix timestamp1705312000
getEnvVar(key)Environment variablegetEnvVar("HOME")
getEnvVar(key, default)With defaultgetEnvVar("API_KEY", "none")
randomInt(min, max)Random integerrandomInt(1, 100)
randomString(len)Random stringrandomString(8)
concat(a, b, ...)Concatenate stringsconcat("a", "b")
toLower(s)LowercasetoLower("ABC") → abc
toUpper(s)UppercasetoUpper("abc") → ABC
trim(s)Trim whitespacetrim(" a ") → a
replace(s, old, new)Replace stringreplace("a.b", ".", "_")
split(s, sep)Split stringsplit("a,b", ",")
join(arr, sep)Join arrayjoin(["a","b"], "-")
execCmd(cmd)Execute commandexecCmd("whoami")
Example: 
params:
  - name: scan_id
    default: "{{uuid()}}"

  - name: date
    default: "{{currentDate()}}"

  - name: user
    default: "{{getEnvVar('USER', 'unknown')}}"

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Template Rendering

Templates are rendered at different stages:

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Step Execution Time

Most fields are rendered just before step execution: 
- name: scan
  type: bash
  command: echo "{{target}}"     # Rendered when step runs

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Foreach Iteration Time

Loop variables are rendered during each iteration: 
- name: process
  type: foreach
  input: "{{Output}}/list.txt"   # {{}} rendered first
  variable: item
  step:
    command: process [[item]]    # [[]] rendered per iteration

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Conditional Templates

Use templates in conditions: 
- name: scan
  type: bash
  pre_condition: 'fileExists("{{Output}}/targets.txt")'
  command: nuclei -l {{Output}}/targets.txt

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Nested Variables

Variables can reference other variables: 
params:
  - name: output_dir
    default: "{{Output}}/scans"

steps:
  - name: scan
    type: bash
    command: subfinder -d {{target}} -o {{output_dir}}/subs.txt
Resolution:
  1. {{output_dir}} resolves to {{Output}}/scans
  2. {{Output}} resolves to workspace path
  3. Final: /home/user/.../workspaces/example.com/scans

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Best Practices

  1. Quote paths with spaces 
    command: cat "{{Output}}/my file.txt"
  2. Use descriptive parameter names 
    params:
  - name: target_domain    # Good
  - name: t                # Bad
  3. Provide defaults when possible 
    params:
  - name: threads
    default: "10"
  4. Document parameters 
    params:
  - name: severity
    default: "high,critical"
    description: Nuclei severity filter
  5. Use built-in paths 
    # Good - uses built-in variables
command: "{{Binaries}}/nuclei -t {{Data}}/templates"

# Bad - hardcoded paths
command: "/usr/local/bin/nuclei -t /opt/templates"

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Next Steps